FFmpeg
bin2c.c
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1 /*
2  * This file is part of FFmpeg.
3  *
4  * Permission is hereby granted, free of charge, to any person obtaining a
5  * copy of this software and associated documentation files (the "Software"),
6  * to deal in the Software without restriction, including without limitation
7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8  * and/or sell copies of the Software, and to permit persons to whom the
9  * Software is furnished to do so, subject to the following conditions:
10  *
11  * The above copyright notice and this permission notice shall be included in
12  * all copies or substantial portions of the Software.
13  *
14  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
17  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
18  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
19  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
20  * DEALINGS IN THE SOFTWARE.
21  */
22 
23 #include <string.h>
24 #include <stdio.h>
25 
26 int main(int argc, char **argv)
27 {
28  const char *name;
29  FILE *input, *output;
30  unsigned int length = 0;
31  unsigned char data;
32 
33  if (argc < 3 || argc > 4)
34  return 1;
35 
36  input = fopen(argv[1], "rb");
37  if (!input)
38  return -1;
39 
40  output = fopen(argv[2], "wb");
41  if (!output)
42  return -1;
43 
44  if (argc == 4) {
45  name = argv[3];
46  } else {
47  size_t arglen = strlen(argv[1]);
48  name = argv[1];
49 
50  for (int i = 0; i < arglen; i++) {
51  if (argv[1][i] == '.')
52  argv[1][i] = '_';
53  else if (argv[1][i] == '/')
54  name = &argv[1][i+1];
55  }
56  }
57 
58  fprintf(output, "const unsigned char ff_%s_data[] = { ", name);
59 
60  while (fread(&data, 1, 1, input) > 0) {
61  fprintf(output, "0x%02x, ", data);
62  length++;
63  }
64 
65  fprintf(output, "0x00 };\n");
66  fprintf(output, "const unsigned int ff_%s_len = %u;\n", name, length);
67 
68  fclose(output);
69 
70  if (ferror(input) || !feof(input))
71  return -1;
72 
73  fclose(input);
74 
75  return 0;
76 }
error
static void error(const char *err)
Definition: target_bsf_fuzzer.c:32
formats
formats
Definition: signature.h:48
ff_get_video_buffer
AVFrame * ff_get_video_buffer(AVFilterLink *link, int w, int h)
Request a picture buffer with a specific set of permissions.
Definition: video.c:112
ff_progress_frame_report
void ff_progress_frame_report(ProgressFrame *f, int n)
Notify later decoding threads when part of their reference frame is ready.
Definition: decode.c:1759
A
#define A(x)
Definition: vpx_arith.h:28
generate
static av_always_inline void generate(int8_t *out, int out_stride, const uint8_t *in, int in_stride, H274FilmGrainDatabase *database, const AVFilmGrainH274Params *h274, int c, int invert, int deblock, int y_offset, int x_offset)
Definition: h274.c:156
ff_get_audio_buffer
AVFrame * ff_get_audio_buffer(AVFilterLink *link, int nb_samples)
Request an audio samples buffer with a specific set of permissions.
Definition: audio.c:97
be
it s the only field you need to keep assuming you have a context There is some magic you don t need to care about around this just let it be(in the first position) for now. Options ------- Then comes the options array. This is what will define the user accessible options. For example
L1
F H1 F F H1 F F F F H1<-F-------F-------F v v v H2 H3 H2 ^ ^ ^ F-------F-------F-> H1<-F-------F-------F|||||||||F H1 F|||||||||F H1 Funavailable fullpel samples(outside the picture for example) shall be equalto the closest available fullpel sampleSmaller pel interpolation:--------------------------if diag_mc is set then points which lie on a line between 2 vertically, horizontally or diagonally adjacent halfpel points shall be interpolatedlinearly with rounding to nearest and halfway values rounded up.points which lie on 2 diagonals at the same time should only use the onediagonal not containing the fullpel point F--> O q O<--h1-> O q O<--F v \/v \/v O O O O O O O|/|\|q q q q q|/|\|O O O O O O O ^/\ ^/\ ^ h2--> O q O<--h3-> O q O<--h2 v \/v \/v O O O O O O O|\|/|q q q q q|\|/|O O O O O O O ^/\ ^/\ ^ F--> O q O<--h1-> O q O<--Fthe remaining points shall be bilinearly interpolated from theup to 4 surrounding halfpel and fullpel points, again rounding should be tonearest and halfway values rounded upcompliant Snow decoders MUST support 1-1/8 pel luma and 1/2-1/16 pel chromainterpolation at leastOverlapped block motion compensation:-------------------------------------FIXMELL band prediction:===================Each sample in the LL0 subband is predicted by the median of the left, top andleft+top-topleft samples, samples outside the subband shall be considered tobe 0. To reverse this prediction in the decoder apply the following.for(y=0;y< height;y++){ for(x=0;x< width;x++){ sample[y][x]+=median(sample[y-1][x], sample[y][x-1], sample[y-1][x]+sample[y][x-1]-sample[y-1][x-1]);}}sample[-1][ *]=sample[ *][-1]=0;width, height here are the width and height of the LL0 subband not of the finalvideoDequantization:===============FIXMEWavelet Transform:==================Snow supports 2 wavelet transforms, the symmetric biorthogonal 5/3 integertransform and an integer approximation of the symmetric biorthogonal 9/7daubechies wavelet.2D IDWT(inverse discrete wavelet transform) --------------------------------------------The 2D IDWT applies a 2D filter recursively, each time combining the4 lowest frequency subbands into a single subband until only 1 subbandremains.The 2D filter is done by first applying a 1D filter in the vertical directionand then applying it in the horizontal one. --------------- --------------- --------------- ---------------|LL0|HL0|||||||||||||---+---|HL1||L0|H0|HL1||LL1|HL1|||||LH0|HH0|||||||||||||-------+-------|-> L1 H1 LH1 HH1 LH1 HH1 LH1 HH1 L1
Definition: snow.txt:554
process
static void process(NormalizeContext *s, AVFrame *in, AVFrame *out)
Definition: vf_normalize.c:155
draw_horiz_band
static void draw_horiz_band(AVCodecContext *ctx, const AVFrame *fr, int offset[4], int slice_position, int type, int height)
Definition: api-band-test.c:37
name
it s the only field you need to keep assuming you have a context There is some magic you don t need to care about around this just let it vf default minimum maximum flags name is the option name
Definition: writing_filters.txt:88
status
they must not be accessed directly The fifo field contains the frames that are queued in the input for processing by the filter The status_in and status_out fields contains the queued status(EOF or error) of the link
entry
#define entry
Definition: aom_film_grain_template.c:66
L2
F H1 F F H1 F F F F H1<-F-------F-------F v v v H2 H3 H2 ^ ^ ^ F-------F-------F-> H1<-F-------F-------F|||||||||F H1 F|||||||||F H1 Funavailable fullpel samples(outside the picture for example) shall be equalto the closest available fullpel sampleSmaller pel interpolation:--------------------------if diag_mc is set then points which lie on a line between 2 vertically, horizontally or diagonally adjacent halfpel points shall be interpolatedlinearly with rounding to nearest and halfway values rounded up.points which lie on 2 diagonals at the same time should only use the onediagonal not containing the fullpel point F--> O q O<--h1-> O q O<--F v \/v \/v O O O O O O O|/|\|q q q q q|/|\|O O O O O O O ^/\ ^/\ ^ h2--> O q O<--h3-> O q O<--h2 v \/v \/v O O O O O O O|\|/|q q q q q|\|/|O O O O O O O ^/\ ^/\ ^ F--> O q O<--h1-> O q O<--Fthe remaining points shall be bilinearly interpolated from theup to 4 surrounding halfpel and fullpel points, again rounding should be tonearest and halfway values rounded upcompliant Snow decoders MUST support 1-1/8 pel luma and 1/2-1/16 pel chromainterpolation at leastOverlapped block motion compensation:-------------------------------------FIXMELL band prediction:===================Each sample in the LL0 subband is predicted by the median of the left, top andleft+top-topleft samples, samples outside the subband shall be considered tobe 0. To reverse this prediction in the decoder apply the following.for(y=0;y< height;y++){ for(x=0;x< width;x++){ sample[y][x]+=median(sample[y-1][x], sample[y][x-1], sample[y-1][x]+sample[y][x-1]-sample[y-1][x-1]);}}sample[-1][ *]=sample[ *][-1]=0;width, height here are the width and height of the LL0 subband not of the finalvideoDequantization:===============FIXMEWavelet Transform:==================Snow supports 2 wavelet transforms, the symmetric biorthogonal 5/3 integertransform and an integer approximation of the symmetric biorthogonal 9/7daubechies wavelet.2D IDWT(inverse discrete wavelet transform) --------------------------------------------The 2D IDWT applies a 2D filter recursively, each time combining the4 lowest frequency subbands into a single subband until only 1 subbandremains.The 2D filter is done by first applying a 1D filter in the vertical directionand then applying it in the horizontal one. --------------- --------------- --------------- ---------------|LL0|HL0|||||||||||||---+---|HL1||L0|H0|HL1||LL1|HL1|||||LH0|HH0|||||||||||||-------+-------|-> L1 H1 LH1 HH1 LH1 HH1 LH1 HH1 L2
Definition: snow.txt:554
level
uint8_t level
Definition: svq3.c:205
program
Undefined Behavior In the C some operations are like signed integer dereferencing freed accessing outside allocated Undefined Behavior must not occur in a C program
Definition: undefined.txt:6
cast
The reader does not expect b to be semantically here and if the code is changed by maybe adding a cast
Definition: undefined.txt:36
mix
static int mix(int c0, int c1)
Definition: 4xm.c:716
AVERROR
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later. That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another. Frame references ownership and permissions
nb_input_files
int nb_input_files
Definition: ffmpeg.c:105
less
static int less(const void *a, const void *b)
Definition: ctu.c:678
space
Undefined Behavior In the C some operations are like signed integer dereferencing freed accessing outside allocated space
Definition: undefined.txt:4
Then
status_out is the status that have been taken into it is final when it is not The typical task of an activate callback is to first check the backward status of output and if relevant forward it to the corresponding input Then
Definition: filter_design.txt:165
out
FILE * out
Definition: movenc.c:55
av_frame_get_buffer
int av_frame_get_buffer(AVFrame *frame, int align)
Allocate new buffer(s) for audio or video data.
Definition: frame.c:288
elements
static const ElemCat * elements[ELEMENT_COUNT]
Definition: signature.h:566
scheduling
===============The purpose of these rules is to ensure that frames flow in the filter graph without getting stuck and accumulating somewhere. Simple filters that output one frame for each input frame should not have to worry about it. There are two design for filters:one using the filter_frame() and request_frame() callbacks and the other using the activate() callback. The design using filter_frame() and request_frame() is legacy, but it is suitable for filters that have a single input and process one frame at a time. New filters with several inputs, that treat several frames at a time or that require a special treatment at EOF should probably use the design using activate(). activate -------- This method is called when something must be done in a filter scheduling
Definition: filter_design.txt:142
MID_STATE
#define MID_STATE
Definition: snow.h:39
cb
static double cb(void *priv, double x, double y)
Definition: vf_geq.c:246
nothing
static void nothing(void *foo)
Definition: dshow_capture.h:52
is
The official guide to swscale for confused that is
Definition: swscale.txt:28
playlist
Definition: hls.c:102
u
#define u(width, name, range_min, range_max)
Definition: cbs_h2645.c:251
inverse
inverse
Definition: af_crystalizer.c:121
developers
The official guide to swscale for confused developers
Definition: swscale.txt:2
ff_filter_frame
int ff_filter_frame(AVFilterLink *link, AVFrame *frame)
Send a frame of data to the next filter.
Definition: avfilter.c:1015
AVERROR_EOF
#define AVERROR_EOF
End of file.
Definition: error.h:57
FFERROR_NOT_READY
return FFERROR_NOT_READY
Definition: filter_design.txt:204
get_format
static int get_format(AVCodecContext *avctx, const enum AVPixelFormat *pix_fmts)
Definition: qsv_decode.c:44
edgedetect
This document is a tutorial initiation for writing simple filters in libavfilter libavfilter is which means that it is highly recommended that you submit your filters to the FFmpeg development mailing list and make sure that they are applied your filters are likely to have a very short lifetime due to more or less regular internal API and a limited and testing changes the pixels in whatever fashion you and outputs the modified frame The most simple way of doing this is to take a similar filter We ll pick edgedetect
Definition: writing_filters.txt:16
mv
static const int8_t mv[256][2]
Definition: 4xm.c:81
output
filter_frame For filters that do not use the this method is called when a frame is pushed to the filter s input It can be called at any time except in a reentrant way If the input frame is enough to produce output
Definition: filter_design.txt:225
transforms
static const struct @119 transforms[18]
inlink
The exact code depends on how similar the blocks are and how related they are to the and needs to apply these operations to the correct inlink or outlink if there are several Macros are available to factor that when no extra processing is inlink
Definition: filter_design.txt:212
basis
static int16_t basis[64][64]
Definition: mpegvideo_enc.c:4196
design
Filter design
Definition: filter_design.txt:2
av_frame_free
void av_frame_free(AVFrame **frame)
Free the frame and any dynamically allocated objects in it, e.g.
Definition: frame.c:160
callbacks
static const OMX_CALLBACKTYPE callbacks
Definition: omx.c:340
AVFrame
This structure describes decoded (raw) audio or video data.
Definition: frame.h:374
av_frame_make_writable
int av_frame_make_writable(AVFrame *frame)
Ensure that the frame data is writable, avoiding data copy if possible.
Definition: frame.c:662
step
trying all byte sequences megabyte in length and selecting the best looking sequence will yield cases to try But a word about which is also called distortion Distortion can be quantified by almost any quality measurement one chooses the sum of squared differences is used but more complex methods that consider psychovisual effects can be used as well It makes no difference in this discussion First step
Definition: rate_distortion.txt:58
w
uint8_t w
Definition: llviddspenc.c:38
Rate
Rate
G723.1 rate values.
Definition: g723_1.h:72
even
Tag MUST be even
Definition: snow.txt:206
sources
Note except for filters that can have queued frames and sources
Definition: filter_design.txt:285
b
#define b
Definition: input.c:41
chroma
static av_always_inline void chroma(WaveformContext *s, AVFrame *in, AVFrame *out, int component, int intensity, int offset_y, int offset_x, int column, int mirror, int jobnr, int nb_jobs)
Definition: vf_waveform.c:1639
table
static const uint16_t table[]
Definition: prosumer.c:203
likely
#define likely(x)
Definition: asm.h:33
ff_progress_frame_get_buffer
int ff_progress_frame_get_buffer(AVCodecContext *avctx, ProgressFrame *f, int flags)
This function sets up the ProgressFrame, i.e.
Definition: decode.c:1717
data
const char data[16]
Definition: mxf.c:148
linear
static int linear(InterplayACMContext *s, unsigned ind, unsigned col)
Definition: interplayacm.c:135
test
Definition: idctdsp.c:35
half
static uint8_t half(int a, int b)
Definition: mobiclip.c:539
high
int high
Definition: dovi_rpuenc.c:38
ff_request_frame
int ff_request_frame(AVFilterLink *link)
Request an input frame from the filter at the other end of the link.
Definition: avfilter.c:463
integer
int integer
Definition: swresample_internal.h:37
possible
the frame and frame reference mechanism is intended to as much as possible
Definition: filter_design.txt:45
git
FFmpeg instead several VMs run on it ffmpeg org and public facing git
Definition: infra.txt:20
F
#define F(x)
filter
void(* filter)(uint8_t *src, int stride, int qscale)
Definition: h263dsp.c:29
allocate
#define allocate(name, size)
Definition: cbs_h2645.c:446
filter
filter_frame For filters that do not use the this method is called when a frame is pushed to the filter s input It can be called at any time except in a reentrant way If the input frame is enough to produce then the filter should push the output frames on the output link immediately As an exception to the previous rule if the input frame is enough to produce several output frames then the filter needs output only at least one per link The additional frames can be left buffered in the filter
Definition: filter_design.txt:228
Frame
Definition: ffplay.c:152
subbands
subbands
Definition: aptx.h:37
processed
status_in is a status change that must be taken into account after all frames in fifo have been processed
Definition: filter_design.txt:159
config_props
static int config_props(AVFilterLink *outlink)
Definition: aeval.c:225
add_bytes
static void add_bytes(HYuvDecContext *s, uint8_t *dst, uint8_t *src, int w)
Definition: huffyuvdec.c:904
put_pixel
static void put_pixel(uint16_t *dst, ptrdiff_t linesize, const int16_t *in, int bits_per_raw_sample)
Add bias value, clamp and output pixels of a slice.
Definition: proresdsp.c:41
though
though
Definition: snow.txt:1
Makefile
s EdgeDetect Foobar g libavfilter vf_edgedetect c libavfilter vf_foobar c edit libavfilter Makefile
Definition: writing_filters.txt:20
FF_FILTER_FORWARD_STATUS_BACK
#define FF_FILTER_FORWARD_STATUS_BACK(outlink, inlink)
Forward the status on an output link to an input link.
Definition: filters.h:199
H0
F H1 F F H1 F F F F H1<-F-------F-------F v v v H2 H3 H2 ^ ^ ^ F-------F-------F-> H1<-F-------F-------F|||||||||F H1 F|||||||||F H1 Funavailable fullpel samples(outside the picture for example) shall be equalto the closest available fullpel sampleSmaller pel interpolation:--------------------------if diag_mc is set then points which lie on a line between 2 vertically, horizontally or diagonally adjacent halfpel points shall be interpolatedlinearly with rounding to nearest and halfway values rounded up.points which lie on 2 diagonals at the same time should only use the onediagonal not containing the fullpel point F--> O q O<--h1-> O q O<--F v \/v \/v O O O O O O O|/|\|q q q q q|/|\|O O O O O O O ^/\ ^/\ ^ h2--> O q O<--h3-> O q O<--h2 v \/v \/v O O O O O O O|\|/|q q q q q|\|/|O O O O O O O ^/\ ^/\ ^ F--> O q O<--h1-> O q O<--Fthe remaining points shall be bilinearly interpolated from theup to 4 surrounding halfpel and fullpel points, again rounding should be tonearest and halfway values rounded upcompliant Snow decoders MUST support 1-1/8 pel luma and 1/2-1/16 pel chromainterpolation at leastOverlapped block motion compensation:-------------------------------------FIXMELL band prediction:===================Each sample in the LL0 subband is predicted by the median of the left, top andleft+top-topleft samples, samples outside the subband shall be considered tobe 0. To reverse this prediction in the decoder apply the following.for(y=0;y< height;y++){ for(x=0;x< width;x++){ sample[y][x]+=median(sample[y-1][x], sample[y][x-1], sample[y-1][x]+sample[y][x-1]-sample[y-1][x-1]);}}sample[-1][ *]=sample[ *][-1]=0;width, height here are the width and height of the LL0 subband not of the finalvideoDequantization:===============FIXMEWavelet Transform:==================Snow supports 2 wavelet transforms, the symmetric biorthogonal 5/3 integertransform and an integer approximation of the symmetric biorthogonal 9/7daubechies wavelet.2D IDWT(inverse discrete wavelet transform) --------------------------------------------The 2D IDWT applies a 2D filter recursively, each time combining the4 lowest frequency subbands into a single subband until only 1 subbandremains.The 2D filter is done by first applying a 1D filter in the vertical directionand then applying it in the horizontal one. --------------- --------------- --------------- ---------------|LL0|HL0|||||||||||||---+---|HL1||L0|H0|HL1||LL1|HL1|||||LH0|HH0|||||||||||||-------+-------|-> L1 H1 LH1 HH1 LH1 HH1 LH1 HH1 H0
Definition: snow.txt:554
tf_sess_config.config
config
Definition: tf_sess_config.py:33
quality
trying all byte sequences megabyte in length and selecting the best looking sequence will yield cases to try But a word about quality
Definition: rate_distortion.txt:12
convert
static void convert(float y, float u, float v, float *b, float *g, float *r)
Definition: exr.c:963
D
D(D(float, sse)
Definition: rematrix_init.c:30
bit
#define bit(string, value)
Definition: cbs_mpeg2.c:56
InputStream
Definition: ffmpeg.h:394
Filter
F H1 F F H1 F F F F H1<-F-------F-------F v v v H2 H3 H2 ^ ^ ^ F-------F-------F-> H1<-F-------F-------F|||||||||F H1 F|||||||||F H1 Funavailable fullpel samples(outside the picture for example) shall be equalto the closest available fullpel sampleSmaller pel interpolation:--------------------------if diag_mc is set then points which lie on a line between 2 vertically, horizontally or diagonally adjacent halfpel points shall be interpolatedlinearly with rounding to nearest and halfway values rounded up.points which lie on 2 diagonals at the same time should only use the onediagonal not containing the fullpel point F--> O q O<--h1-> O q O<--F v \/v \/v O O O O O O O|/|\|q q q q q|/|\|O O O O O O O ^/\ ^/\ ^ h2--> O q O<--h3-> O q O<--h2 v \/v \/v O O O O O O O|\|/|q q q q q|\|/|O O O O O O O ^/\ ^/\ ^ F--> O q O<--h1-> O q O<--Fthe remaining points shall be bilinearly interpolated from theup to 4 surrounding halfpel and fullpel points, again rounding should be tonearest and halfway values rounded upcompliant Snow decoders MUST support 1-1/8 pel luma and 1/2-1/16 pel chromainterpolation at leastOverlapped block motion compensation:-------------------------------------FIXMELL band prediction:===================Each sample in the LL0 subband is predicted by the median of the left, top andleft+top-topleft samples, samples outside the subband shall be considered tobe 0. To reverse this prediction in the decoder apply the following.for(y=0;y< height;y++){ for(x=0;x< width;x++){ sample[y][x]+=median(sample[y-1][x], sample[y][x-1], sample[y-1][x]+sample[y][x-1]-sample[y-1][x-1]);}}sample[-1][ *]=sample[ *][-1]=0;width, height here are the width and height of the LL0 subband not of the finalvideoDequantization:===============FIXMEWavelet Transform:==================Snow supports 2 wavelet transforms, the symmetric biorthogonal 5/3 integertransform and an integer approximation of the symmetric biorthogonal 9/7daubechies wavelet.2D IDWT(inverse discrete wavelet transform) --------------------------------------------The 2D IDWT applies a 2D filter recursively, each time combining the4 lowest frequency subbands into a single subband until only 1 subbandremains.The 2D filter is done by first applying a 1D filter in the vertical directionand then applying it in the horizontal one. --------------- --------------- --------------- ---------------|LL0|HL0|||||||||||||---+---|HL1||L0|H0|HL1||LL1|HL1|||||LH0|HH0|||||||||||||-------+-------|-> L1 H1 LH1 HH1 LH1 HH1 LH1 HH1 Filter
Definition: snow.txt:554
ff_inlink_consume_frame
int ff_inlink_consume_frame(AVFilterLink *link, AVFrame **rframe)
Take a frame from the link's FIFO and update the link's stats.
Definition: avfilter.c:1442
return
these buffered frames must be flushed immediately if a new input produces new the filter must not call request_frame to get more It must just process the frame or queue it The task of requesting more frames is left to the filter s request_frame method or the application If a filter has several the filter must be ready for frames arriving randomly on any input any filter with several inputs will most likely require some kind of queuing mechanism It is perfectly acceptable to have a limited queue and to drop frames when the inputs are too unbalanced request_frame For filters that do not use the this method is called when a frame is wanted on an output For a it should directly call filter_frame on the corresponding output For a if there are queued frames already one of these frames should be pushed If the filter should request a frame on one of its repeatedly until at least one frame has been pushed Return or at least make progress towards producing a it should return
Definition: filter_design.txt:264
rgb
Definition: rpzaenc.c:60
some
Undefined Behavior In the C some operations are like signed integer dereferencing freed accessing outside allocated Undefined Behavior must not occur in a C it is not safe even if the output of undefined operations is unused The unsafety may seem nit picking but Optimizing compilers have in fact optimized code on the assumption that no undefined Behavior occurs Optimizing code based on wrong assumptions can and has in some cases lead to effects beyond the output of computations The signed integer overflow problem in speed critical code Code which is highly optimized and works with signed integers sometimes has the problem that some(invalid) inputs can trigger overflows(undefined behavior). In these cases
decoder
static const chunk_decoder decoder[8]
Definition: dfa.c:331
reasons
if it could not for temporary reasons
Definition: filter_design.txt:265
resolution
The official guide to swscale for confused that consecutive non overlapping rectangles of slice_bottom special converter These generally are unscaled converters of common like for each output line the vertical scaler pulls lines from a ring buffer When the ring buffer does not contain the wanted then it is pulled from the input slice through the input converter and horizontal scaler The result is also stored in the ring buffer to serve future vertical scaler requests When no more output can be generated because lines from a future slice would be then all remaining lines in the current slice are horizontally scaled and put in the ring buffer[This is done for luma and chroma, each with possibly different numbers of lines per picture.] Input to YUV Converter When the input to the main path is not planar bits per component YUV or bit it is converted to planar bit YUV Two sets of converters exist for this the other leaves the full chroma resolution
Definition: swscale.txt:54
frames
if it could not because there are no more frames
Definition: filter_design.txt:266
relevant
status_out is the status that have been taken into it is final when it is not The typical task of an activate callback is to first check the backward status of output and if relevant forward it to the corresponding input if relevant
Definition: filter_design.txt:165
IA
#define IA(x)
Definition: cast5.c:30
tables
Writing a table generator This documentation is preliminary Parts of the API are not good and should be changed Basic concepts A table generator consists of two *_tablegen c and *_tablegen h The h file will provide the variable declarations and initialization code for the tables
Definition: tablegen.txt:10
future
FFmpeg s bug feature request tracker new issues and changes to existing issues can be done through a web interface Issues can be different kinds of things we want to keep track of but that do not belong into the source tree itself This includes bug feature requests and license violations We might add more items to this list in the future
Definition: issue_tracker.txt:13
variant
Definition: hls.c:193
type
it s the only field you need to keep assuming you have a context There is some magic you don t need to care about around this just let it vf type
Definition: writing_filters.txt:86
update
static av_always_inline void update(SilenceDetectContext *s, AVFrame *insamples, int is_silence, int current_sample, int64_t nb_samples_notify, AVRational time_base)
Definition: af_silencedetect.c:78
pts
static int64_t pts
Definition: transcode_aac.c:644
account
status_out is the status that have been taken into account
Definition: filter_design.txt:160
fast
static int fast
Definition: ffplay.c:328
planar
uint8_t pi<< 24) CONV_FUNC(AV_SAMPLE_FMT_S64, int64_t, AV_SAMPLE_FMT_U8,(uint64_t)((*(const uint8_t *) pi - 0x80U))<< 56) CONV_FUNC(AV_SAMPLE_FMT_FLT, float, AV_SAMPLE_FMT_U8,(*(const uint8_t *) pi - 0x80) *(1.0f/(1<< 7))) CONV_FUNC(AV_SAMPLE_FMT_DBL, double, AV_SAMPLE_FMT_U8,(*(const uint8_t *) pi - 0x80) *(1.0/(1<< 7))) CONV_FUNC(AV_SAMPLE_FMT_U8, uint8_t, AV_SAMPLE_FMT_S16,(*(const int16_t *) pi >>8)+0x80) CONV_FUNC(AV_SAMPLE_FMT_S32, int32_t, AV_SAMPLE_FMT_S16, *(const int16_t *) pi *(1<< 16)) CONV_FUNC(AV_SAMPLE_FMT_S64, int64_t, AV_SAMPLE_FMT_S16,(uint64_t)(*(const int16_t *) pi)<< 48) CONV_FUNC(AV_SAMPLE_FMT_FLT, float, AV_SAMPLE_FMT_S16, *(const int16_t *) pi *(1.0f/(1<< 15))) CONV_FUNC(AV_SAMPLE_FMT_DBL, double, AV_SAMPLE_FMT_S16, *(const int16_t *) pi *(1.0/(1<< 15))) CONV_FUNC(AV_SAMPLE_FMT_U8, uint8_t, AV_SAMPLE_FMT_S32,(*(const int32_t *) pi >>24)+0x80) CONV_FUNC(AV_SAMPLE_FMT_S64, int64_t, AV_SAMPLE_FMT_S32,(uint64_t)(*(const int32_t *) pi)<< 32) CONV_FUNC(AV_SAMPLE_FMT_FLT, float, AV_SAMPLE_FMT_S32, *(const int32_t *) pi *(1.0f/(1U<< 31))) CONV_FUNC(AV_SAMPLE_FMT_DBL, double, AV_SAMPLE_FMT_S32, *(const int32_t *) pi *(1.0/(1U<< 31))) CONV_FUNC(AV_SAMPLE_FMT_U8, uint8_t, AV_SAMPLE_FMT_S64,(*(const int64_t *) pi >>56)+0x80) CONV_FUNC(AV_SAMPLE_FMT_FLT, float, AV_SAMPLE_FMT_S64, *(const int64_t *) pi *(1.0f/(UINT64_C(1)<< 63))) CONV_FUNC(AV_SAMPLE_FMT_DBL, double, AV_SAMPLE_FMT_S64, *(const int64_t *) pi *(1.0/(UINT64_C(1)<< 63))) CONV_FUNC(AV_SAMPLE_FMT_U8, uint8_t, AV_SAMPLE_FMT_FLT, av_clip_uint8(lrintf(*(const float *) pi *(1<< 7))+0x80)) CONV_FUNC(AV_SAMPLE_FMT_S16, int16_t, AV_SAMPLE_FMT_FLT, av_clip_int16(lrintf(*(const float *) pi *(1<< 15)))) CONV_FUNC(AV_SAMPLE_FMT_S32, int32_t, AV_SAMPLE_FMT_FLT, av_clipl_int32(llrintf(*(const float *) pi *(1U<< 31)))) CONV_FUNC(AV_SAMPLE_FMT_S64, int64_t, AV_SAMPLE_FMT_FLT, llrintf(*(const float *) pi *(UINT64_C(1)<< 63))) CONV_FUNC(AV_SAMPLE_FMT_U8, uint8_t, AV_SAMPLE_FMT_DBL, av_clip_uint8(lrint(*(const double *) pi *(1<< 7))+0x80)) CONV_FUNC(AV_SAMPLE_FMT_S16, int16_t, AV_SAMPLE_FMT_DBL, av_clip_int16(lrint(*(const double *) pi *(1<< 15)))) CONV_FUNC(AV_SAMPLE_FMT_S32, int32_t, AV_SAMPLE_FMT_DBL, av_clipl_int32(llrint(*(const double *) pi *(1U<< 31)))) CONV_FUNC(AV_SAMPLE_FMT_S64, int64_t, AV_SAMPLE_FMT_DBL, llrint(*(const double *) pi *(UINT64_C(1)<< 63))) #define FMT_PAIR_FUNC(out, in) static conv_func_type *const fmt_pair_to_conv_functions[AV_SAMPLE_FMT_NB *AV_SAMPLE_FMT_NB]={ FMT_PAIR_FUNC(AV_SAMPLE_FMT_U8, AV_SAMPLE_FMT_U8), FMT_PAIR_FUNC(AV_SAMPLE_FMT_S16, AV_SAMPLE_FMT_U8), FMT_PAIR_FUNC(AV_SAMPLE_FMT_S32, AV_SAMPLE_FMT_U8), FMT_PAIR_FUNC(AV_SAMPLE_FMT_FLT, AV_SAMPLE_FMT_U8), FMT_PAIR_FUNC(AV_SAMPLE_FMT_DBL, AV_SAMPLE_FMT_U8), FMT_PAIR_FUNC(AV_SAMPLE_FMT_S64, AV_SAMPLE_FMT_U8), FMT_PAIR_FUNC(AV_SAMPLE_FMT_U8, AV_SAMPLE_FMT_S16), FMT_PAIR_FUNC(AV_SAMPLE_FMT_S16, AV_SAMPLE_FMT_S16), FMT_PAIR_FUNC(AV_SAMPLE_FMT_S32, AV_SAMPLE_FMT_S16), FMT_PAIR_FUNC(AV_SAMPLE_FMT_FLT, AV_SAMPLE_FMT_S16), FMT_PAIR_FUNC(AV_SAMPLE_FMT_DBL, AV_SAMPLE_FMT_S16), FMT_PAIR_FUNC(AV_SAMPLE_FMT_S64, AV_SAMPLE_FMT_S16), FMT_PAIR_FUNC(AV_SAMPLE_FMT_U8, AV_SAMPLE_FMT_S32), FMT_PAIR_FUNC(AV_SAMPLE_FMT_S16, AV_SAMPLE_FMT_S32), FMT_PAIR_FUNC(AV_SAMPLE_FMT_S32, AV_SAMPLE_FMT_S32), FMT_PAIR_FUNC(AV_SAMPLE_FMT_FLT, AV_SAMPLE_FMT_S32), FMT_PAIR_FUNC(AV_SAMPLE_FMT_DBL, AV_SAMPLE_FMT_S32), FMT_PAIR_FUNC(AV_SAMPLE_FMT_S64, AV_SAMPLE_FMT_S32), FMT_PAIR_FUNC(AV_SAMPLE_FMT_U8, AV_SAMPLE_FMT_FLT), FMT_PAIR_FUNC(AV_SAMPLE_FMT_S16, AV_SAMPLE_FMT_FLT), FMT_PAIR_FUNC(AV_SAMPLE_FMT_S32, AV_SAMPLE_FMT_FLT), FMT_PAIR_FUNC(AV_SAMPLE_FMT_FLT, AV_SAMPLE_FMT_FLT), FMT_PAIR_FUNC(AV_SAMPLE_FMT_DBL, AV_SAMPLE_FMT_FLT), FMT_PAIR_FUNC(AV_SAMPLE_FMT_S64, AV_SAMPLE_FMT_FLT), FMT_PAIR_FUNC(AV_SAMPLE_FMT_U8, AV_SAMPLE_FMT_DBL), FMT_PAIR_FUNC(AV_SAMPLE_FMT_S16, AV_SAMPLE_FMT_DBL), FMT_PAIR_FUNC(AV_SAMPLE_FMT_S32, AV_SAMPLE_FMT_DBL), FMT_PAIR_FUNC(AV_SAMPLE_FMT_FLT, AV_SAMPLE_FMT_DBL), FMT_PAIR_FUNC(AV_SAMPLE_FMT_DBL, AV_SAMPLE_FMT_DBL), FMT_PAIR_FUNC(AV_SAMPLE_FMT_S64, AV_SAMPLE_FMT_DBL), FMT_PAIR_FUNC(AV_SAMPLE_FMT_U8, AV_SAMPLE_FMT_S64), FMT_PAIR_FUNC(AV_SAMPLE_FMT_S16, AV_SAMPLE_FMT_S64), FMT_PAIR_FUNC(AV_SAMPLE_FMT_S32, AV_SAMPLE_FMT_S64), FMT_PAIR_FUNC(AV_SAMPLE_FMT_FLT, AV_SAMPLE_FMT_S64), FMT_PAIR_FUNC(AV_SAMPLE_FMT_DBL, AV_SAMPLE_FMT_S64), FMT_PAIR_FUNC(AV_SAMPLE_FMT_S64, AV_SAMPLE_FMT_S64), };static void cpy1(uint8_t **dst, const uint8_t **src, int len){ memcpy(*dst, *src, len);} static void cpy2(uint8_t **dst, const uint8_t **src, int len){ memcpy(*dst, *src, 2 *len);} static void cpy4(uint8_t **dst, const uint8_t **src, int len){ memcpy(*dst, *src, 4 *len);} static void cpy8(uint8_t **dst, const uint8_t **src, int len){ memcpy(*dst, *src, 8 *len);} AudioConvert *swri_audio_convert_alloc(enum AVSampleFormat out_fmt, enum AVSampleFormat in_fmt, int channels, const int *ch_map, int flags) { AudioConvert *ctx;conv_func_type *f=fmt_pair_to_conv_functions[av_get_packed_sample_fmt(out_fmt)+AV_SAMPLE_FMT_NB *av_get_packed_sample_fmt(in_fmt)];if(!f) return NULL;ctx=av_mallocz(sizeof(*ctx));if(!ctx) return NULL;if(channels==1){ in_fmt=av_get_planar_sample_fmt(in_fmt);out_fmt=av_get_planar_sample_fmt(out_fmt);} ctx->channels=channels;ctx->conv_f=f;ctx->ch_map=ch_map;if(in_fmt==AV_SAMPLE_FMT_U8||in_fmt==AV_SAMPLE_FMT_U8P) memset(ctx->silence, 0x80, sizeof(ctx->silence));if(out_fmt==in_fmt &&!ch_map) { switch(av_get_bytes_per_sample(in_fmt)){ case 1:ctx->simd_f=cpy1;break;case 2:ctx->simd_f=cpy2;break;case 4:ctx->simd_f=cpy4;break;case 8:ctx->simd_f=cpy8;break;} } return ctx;} void swri_audio_convert_free(AudioConvert **ctx) { av_freep(ctx);} int swri_audio_convert(AudioConvert *ctx, AudioData *out, AudioData *in, int len) { int ch;int off=0;const int os=(out->planar ? 1 :out->ch_count) *out->bps;unsigned misaligned=0;av_assert0(ctx->channels==out->ch_count);if(ctx->in_simd_align_mask) { int planes=in->planar ? in->ch_count :1;unsigned m=0;for(ch=0;ch< planes;ch++) m|=(intptr_t) in->ch[ch];misaligned|=m &ctx->in_simd_align_mask;} if(ctx->out_simd_align_mask) { int planes=out->planar ? out->ch_count :1;unsigned m=0;for(ch=0;ch< planes;ch++) m|=(intptr_t) out->ch[ch];misaligned|=m &ctx->out_simd_align_mask;} if(ctx->simd_f &&!ctx->ch_map &&!misaligned){ off=len &~15;av_assert1(off >=0);av_assert1(off<=len);av_assert2(ctx->channels==SWR_CH_MAX||!in->ch[ctx->channels]);if(off >0){ if(out->planar==in->planar){ int planes=out->planar ? out->ch_count :1;for(ch=0;ch< planes;ch++){ ctx->simd_f(out->ch+ch,(const uint8_t **) in->ch+ch, off *(out-> planar
Definition: audioconvert.c:56
idct
static void idct(int16_t block[64])
Definition: 4xm.c:167
once
static pthread_once_t once
Definition: ffjni.c:38
InputFile
Definition: ffmpeg.h:436
AVFilterPad
A filter pad used for either input or output.
Definition: internal.h:33
qlogs
spatial_decomposition_type s header_state qlog s header_state mv_scale s header_state qbias s header_state block_max_depth s header_state qlogs
Definition: snow.txt:85
LH
#define LH(psrc)
Definition: generic_macros_msa.h:89
aligned
static int aligned(int val)
Definition: dashdec.c:171
C
s EdgeDetect Foobar g libavfilter vf_edgedetect c libavfilter vf_foobar c edit libavfilter and add an entry for foobar following the pattern of the other filters edit libavfilter allfilters and add an entry for foobar following the pattern of the other filters configure make j< whatever > ffmpeg ffmpeg i you should get a foobar png with Lena edge detected That s your new playground is ready Some little details about what s going which in turn will define variables for the build system and the C
Definition: writing_filters.txt:58
first
trying all byte sequences megabyte in length and selecting the best looking sequence will yield cases to try But first
Definition: rate_distortion.txt:12
variables
FFmpeg currently uses a custom build this text attempts to document some of its obscure features and options Makefile variables
Definition: build_system.txt:7
help
static void help(void)
Definition: dct.c:454
description
Tag description
Definition: snow.txt:206
initFilter
static av_cold int initFilter(int16_t **outFilter, int32_t **filterPos, int *outFilterSize, int xInc, int srcW, int dstW, int filterAlign, int one, int flags, int cpu_flags, SwsVector *srcFilter, SwsVector *dstFilter, double param[2], int srcPos, int dstPos)
Definition: utils.c:418
main
int main
Definition: dovi_rpuenc.c:37
ff_set_common_formats
int ff_set_common_formats(AVFilterContext *ctx, AVFilterFormats *formats)
A helper for query_formats() which sets all links to the same list of formats.
Definition: formats.c:868
set
static void set(uint8_t *a[], int ch, int index, int ch_count, enum AVSampleFormat f, double v)
Definition: swresample.c:59
check
#define check(x, y, S, v)
Definition: motion_est_template.c:405
YUV
The official guide to swscale for confused that consecutive non overlapping rectangles of slice_bottom special converter These generally are unscaled converters of common like YUV
Definition: swscale.txt:38
decode
static void decode(AVCodecContext *dec_ctx, AVPacket *pkt, AVFrame *frame, FILE *outfile)
Definition: decode_audio.c:72
ff_outlink_set_status
static void ff_outlink_set_status(AVFilterLink *link, int status, int64_t pts)
Set the status field of a link from the source filter.
Definition: filters.h:189
ff_inlink_request_frame
void ff_inlink_request_frame(AVFilterLink *link)
Mark that a frame is wanted on the link.
Definition: avfilter.c:1568
width
#define width
matter
Undefined Behavior In the C some operations are like signed integer dereferencing freed accessing outside allocated Undefined Behavior must not occur in a C it is not safe even if the output of undefined operations is unused The unsafety may seem nit picking but Optimizing compilers have in fact optimized code on the assumption that no undefined Behavior occurs Optimizing code based on wrong assumptions can and has in some cases lead to effects beyond the output of computations The signed integer overflow problem in speed critical code Code which is highly optimized and works with signed integers sometimes has the problem that often the output of the computation does not matter(as it is from invalid input). In some cases the input can be checked easily in others checking the input is computationally too intensive. In these remaining cases a unsigned type can be used instead of a signed type. unsigned overflows are defined in C. SUINT ----- As we have above established there is a need to use "unsigned" sometimes in computations which work with signed integers(which overflow). Using "unsigned" for signed integers has the very significant potential to cause confusion as in unsigned a
s
#define s(width, name)
Definition: cbs_vp9.c:198
offsets
static const int offsets[]
Definition: hevc_pel.c:34
format
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample format(the sample packing is implied by the sample format) and sample rate. The lists are not just lists
SWS_FULL_CHR_H_INP
#define SWS_FULL_CHR_H_INP
Definition: swscale.h:88
g
const char * g
Definition: vf_curves.c:128
changes
This document is a tutorial initiation for writing simple filters in libavfilter libavfilter is which means that it is highly recommended that you submit your filters to the FFmpeg development mailing list and make sure that they are applied your filters are likely to have a very short lifetime due to more or less regular internal API changes
Definition: writing_filters.txt:8
ff_thread_get_buffer
int ff_thread_get_buffer(AVCodecContext *avctx, AVFrame *f, int flags)
Wrapper around get_buffer() for frame-multithreaded codecs.
Definition: pthread_frame.c:986
info
MIPS optimizations info
Definition: mips.txt:2
bits
uint8_t bits
Definition: vp3data.h:128
filters
#define filters(fmt, type, inverse, clp, inverset, clip, one, clip_fn, packed)
Definition: af_crystalizer.c:54
from
const char * from
Definition: jacosubdec.c:66
to
const char * to
Definition: webvttdec.c:35
form
This is the more generic form
Definition: tablegen.txt:34
reaction
Note except for filters that can have queued frames and request_frame does not push and as a reaction
Definition: filter_design.txt:287
data
the buffer is automatically deallocated once all corresponding references have been destroyed The characteristics of the data(resolution, sample rate, etc.) are stored in the reference
AVFilter::flags
int flags
A combination of AVFILTER_FLAG_*.
Definition: avfilter.h:210
ctx
AVFormatContext * ctx
Definition: movenc.c:49
ff_progress_frame_await
the pkt_dts and pkt_pts fields in AVFrame will work as usual Restrictions on codec whose streams don t reset across will not work because their bitstreams cannot be decoded in parallel *The contents of buffers must not be read before ff_progress_frame_await() has been called on them. reget_buffer() and buffer age optimizations no longer work. *The contents of buffers must not be written to after ff_progress_frame_report() has been called on them. This includes draw_edges(). Porting codecs to frame threading
channels
channels
Definition: aptx.h:31
pointers
Undefined Behavior In the C some operations are like signed integer dereferencing freed pointers
Definition: undefined.txt:4
htaps
static const double htaps[HTAPS]
The 2nd half (48 coeffs) of a 96-tap symmetric lowpass filter.
Definition: dsd.c:52
Slice
Definition: magicyuv.c:40
on
s EdgeDetect Foobar g libavfilter vf_edgedetect c libavfilter vf_foobar c edit libavfilter and add an entry for foobar following the pattern of the other filters edit libavfilter allfilters and add an entry for foobar following the pattern of the other filters configure make j< whatever > ffmpeg ffmpeg i you should get a foobar png with Lena edge detected That s your new playground is ready Some little details about what s going on
Definition: writing_filters.txt:34
field
it s the only field you need to keep assuming you have a context There is some magic you don t need to care about around this field
Definition: writing_filters.txt:78
write_fileheader
write_fileheader() adds some minor things like a "this is a generated file" comment and some standard includes. tablegen.h defines some write functions for one- and two-dimensional arrays for standard types - they print only the "core" parts so they are easier to reuse for multi-dimensional arrays so the outermost
Definition: tablegen.txt:39
pix_norm1
static int pix_norm1(const uint8_t *pix, int line_size, int w)
Definition: snowenc.c:322
export
static int export(AVFilterContext *ctx, StreamContext *sc, int input)
Definition: vf_signature.c:562
clients
=============================================Slice threading - *The client 's draw_horiz_band() must be thread-safe according to the comment in avcodec.h. Frame threading - *Restrictions with slice threading also apply. *Custom get_buffer2() and get_format() callbacks must be thread-safe. *There is one frame of delay added for every thread beyond the first one. Clients must be able to handle this clients
Definition: multithreading.txt:25
key
const char * key
Definition: hwcontext_opencl.c:189
XMM_CLOBBERS
#define XMM_CLOBBERS(...)
Definition: asm.h:98
Git
FFmpeg instead several VMs run on it ffmpeg org and public facing also website git fftrac this part is build by a cronjob So is the doxygen stuff as well as the FFmpeg git snapshot These scripts are under the ffcron user Git
Definition: infra.txt:58
command
static int command(AVFilterContext *ctx, const char *cmd, const char *arg, char *res, int res_len, int flags)
Definition: vf_drawtext.c:1186
link
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a link
Definition: filter_design.txt:23
ff_inlink_make_frame_writable
int ff_inlink_make_frame_writable(AVFilterLink *link, AVFrame **rframe)
Make sure a frame is writable.
Definition: avfilter.c:1489
callback
static void callback(void *priv_data, int index, uint8_t *buf, int buf_size, int64_t time, enum dshowDeviceType devtype)
Definition: dshow.c:342
Infrastructure
FFmpeg Infrastructure
Definition: infra.txt:15
included
must be printed separately If there s no standard function for printing the type you the WRITE_1D_FUNC_ARGV macro is a very quick way to create one See libavcodec dv_tablegen c for an example The h file This file should the initialization functions should not do and instead of the variable declarations the generated *_tables h file should be included Since that will be generated in the build the path must be included
Definition: tablegen.txt:59
fields
the definition of that something depends on the semantic of the filter The callback must examine the status of the filter s links and proceed accordingly The status of output links is stored in the status_in and status_out fields and tested by the then the processing requires a frame on this link and the filter is expected to make efforts in that direction The status of input links is stored by the fifo and status_out fields
Definition: filter_design.txt:155
if
if(ret)
Definition: filter_design.txt:179
H2
vertical halfpel samples are found by H2[y][x]
Definition: snow.txt:421
context
it s the only field you need to keep assuming you have a context There is some magic you don t need to care about around this just let it vf default minimum maximum flags name is the option keep it simple and lowercase description are in without and describe what they for example set the foo of the bar offset is the offset of the field in your context
Definition: writing_filters.txt:91
AV_CODEC_CAP_FRAME_THREADS
#define AV_CODEC_CAP_FRAME_THREADS
Codec supports frame-level multithreading.
Definition: codec.h:110
negotiation
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format negotiation
Definition: filter_design.txt:12
need
must be printed separately If there s no standard function for printing the type you need
Definition: tablegen.txt:45
quant_table
static const int16_t quant_table[64]
Definition: intrax8.c:517
draw_edges
the pkt_dts and pkt_pts fields in AVFrame will work as usual Restrictions on codec whose streams don t reset across will not work because their bitstreams cannot be decoded in parallel *The contents of buffers must not be read before as well as code calling up to before the decode process starts Call have as it s useful too and the implementation is trivial when you re doing this Note that draw_edges() needs to be called before reporting progress. Before accessing a reference frame or its MVs
result
and forward the result(frame or status change) to the corresponding input. If nothing is possible
frames
the pkt_dts and pkt_pts fields in AVFrame will work as usual Restrictions on codec whose streams don t reset across frames
Definition: multithreading.txt:36
av_frame_copy_props
int av_frame_copy_props(AVFrame *dst, const AVFrame *src)
Copy only "metadata" fields from src to dst.
Definition: frame.c:709
run
uint8_t run
Definition: svq3.c:204
VM
FFmpeg instead several VMs run on it ffmpeg org VM
Definition: infra.txt:20
bias
static int bias(int x, int c)
Definition: vqcdec.c:115
push
static void push(HysteresisContext *s, int x, int y, int w)
Definition: vf_hysteresis.c:140
pixel
uint8_t pixel
Definition: tiny_ssim.c:41
anything
must be printed separately If there s no standard function for printing the type you the WRITE_1D_FUNC_ARGV macro is a very quick way to create one See libavcodec dv_tablegen c for an example The h file This file should the initialization functions should not do anything
Definition: tablegen.txt:56
frame_wanted_out
the definition of that something depends on the semantic of the filter The callback must examine the status of the filter s links and proceed accordingly The status of output links is stored in the frame_wanted_out
Definition: filter_design.txt:148
LIBAVFILTER_VERSION_MICRO
#define LIBAVFILTER_VERSION_MICRO
Definition: version.h:35
contain
must be printed separately If there s no standard function for printing the type you the WRITE_1D_FUNC_ARGV macro is a very quick way to create one See libavcodec dv_tablegen c for an example The h file This file should contain
Definition: tablegen.txt:55
transform
static const int8_t transform[32][32]
Definition: hevcdsp.c:27
period
it s the only field you need to keep assuming you have a context There is some magic you don t need to care about around this just let it vf default minimum maximum flags name is the option keep it simple and lowercase description are in without period
Definition: writing_filters.txt:89
coefficients
static double coefficients[8 *8]
Definition: dctref.c:35
greater
static int greater(MetadataContext *s, const char *value1, const char *value2)
Definition: f_metadata.c:163
activate
filter_frame For filters that do not use the activate() callback
H
F H1 F F H1 F F F F H1<-F-------F-------F v v v H2 H3 H2 ^ ^ ^ F-------F-------F-> H1<-F-------F-------F|||||||||F H1 F|||||||||F H1 Funavailable fullpel samples(outside the picture for example) shall be equalto the closest available fullpel sampleSmaller pel interpolation:--------------------------if diag_mc is set then points which lie on a line between 2 vertically, horizontally or diagonally adjacent halfpel points shall be interpolatedlinearly with rounding to nearest and halfway values rounded up.points which lie on 2 diagonals at the same time should only use the onediagonal not containing the fullpel point F--> O q O<--h1-> O q O<--F v \/v \/v O O O O O O O|/|\|q q q q q|/|\|O O O O O O O ^/\ ^/\ ^ h2--> O q O<--h3-> O q O<--h2 v \/v \/v O O O O O O O|\|/|q q q q q|\|/|O O O O O O O ^/\ ^/\ ^ F--> O q O<--h1-> O q O<--Fthe remaining points shall be bilinearly interpolated from theup to 4 surrounding halfpel and fullpel points, again rounding should be tonearest and halfway values rounded upcompliant Snow decoders MUST support 1-1/8 pel luma and 1/2-1/16 pel chromainterpolation at leastOverlapped block motion compensation:-------------------------------------FIXMELL band prediction:===================Each sample in the LL0 subband is predicted by the median of the left, top andleft+top-topleft samples, samples outside the subband shall be considered tobe 0. To reverse this prediction in the decoder apply the following.for(y=0;y< height;y++){ for(x=0;x< width;x++){ sample[y][x]+=median(sample[y-1][x], sample[y][x-1], sample[y-1][x]+sample[y][x-1]-sample[y-1][x-1]);}}sample[-1][ *]=sample[ *][-1]=0;width, height here are the width and height of the LL0 subband not of the finalvideoDequantization:===============FIXMEWavelet Transform:==================Snow supports 2 wavelet transforms, the symmetric biorthogonal 5/3 integertransform and an integer approximation of the symmetric biorthogonal 9/7daubechies wavelet.2D IDWT(inverse discrete wavelet transform) --------------------------------------------The 2D IDWT applies a 2D filter recursively, each time combining the4 lowest frequency subbands into a single subband until only 1 subbandremains.The 2D filter is done by first applying a 1D filter in the vertical directionand then applying it in the horizontal one. --------------- --------------- --------------- ---------------|LL0|HL0|||||||||||||---+---|HL1||L0|H0|HL1||LL1|HL1|||||LH0|HH0|||||||||||||-------+-------|-> L1 H1 LH1 HH1 LH1 HH1 LH1 HH1 this can end with a L or a H
Definition: snow.txt:555
system
FFmpeg currently uses a custom build system
Definition: build_system.txt:1
V
#define V
Definition: avdct.c:31
work
must be printed separately If there s no standard function for printing the type you the WRITE_1D_FUNC_ARGV macro is a very quick way to create one See libavcodec dv_tablegen c for an example The h file This file should the initialization functions should not do and instead of the variable declarations the generated *_tables h file should be included Since that will be generated in the build the path must be i e not Makefile changes To make the automatic table creation work
Definition: tablegen.txt:66
L0
#define L0
Definition: hevcdec.h:57
list
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining list
Definition: filter_design.txt:25
flush
void(* flush)(AVBSFContext *ctx)
Definition: dts2pts.c:368
not
these buffered frames must be flushed immediately if a new input produces new the filter must not call request_frame to get more It must just process the frame or queue it The task of requesting more frames is left to the filter s request_frame method or the application If a filter has several the filter must be ready for frames arriving randomly on any input any filter with several inputs will most likely require some kind of queuing mechanism It is perfectly acceptable to have a limited queue and to drop frames when the inputs are too unbalanced request_frame For filters that do not use the this method is called when a frame is wanted on an output For a it should directly call filter_frame on the corresponding output For a if there are queued frames already one of these frames should be pushed If not
Definition: filter_design.txt:259
Prediction
Prediction
Definition: magicyuv.c:45
codecs
static const struct codec_string codecs[]
difference
static void difference(IPlane *g, IPlane *f, int y0, int y1)
Definition: vf_morpho.c:495
particular
different references for the same buffer can show different characteristics In particular
Definition: filter_design.txt:55
av_cpu_max_align
size_t av_cpu_max_align(void)
Get the maximum data alignment that may be required by FFmpeg.
Definition: cpu.c:270
abs
#define abs(x)
Definition: cuda_runtime.h:35
filter_frame
static int filter_frame(DBEDecodeContext *s, AVFrame *frame)
Definition: dolby_e.c:1059
inputs
these buffered frames must be flushed immediately if a new input produces new the filter must not call request_frame to get more It must just process the frame or queue it The task of requesting more frames is left to the filter s request_frame method or the application If a filter has several inputs
Definition: filter_design.txt:243
get
static void get(const uint8_t *pixels, int stride, int16_t *block)
Definition: proresenc_anatoliy.c:317
resample
static int resample(SwrContext *s, AudioData *out_param, int out_count, const AudioData *in_param, int in_count)
Definition: swresample.c:490
ff_inlink_acknowledge_status
int ff_inlink_acknowledge_status(AVFilterLink *link, int *rstatus, int64_t *rpts)
Test and acknowledge the change of status on the link.
Definition: avfilter.c:1389
Range
Definition: vf_colorbalance.c:37
index
int index
Definition: gxfenc.c:90
c
Undefined Behavior In the C some operations are like signed integer dereferencing freed accessing outside allocated Undefined Behavior must not occur in a C it is not safe even if the output of undefined operations is unused The unsafety may seem nit picking but Optimizing compilers have in fact optimized code on the assumption that no undefined Behavior occurs Optimizing code based on wrong assumptions can and has in some cases lead to effects beyond the output of computations The signed integer overflow problem in speed critical code Code which is highly optimized and works with signed integers sometimes has the problem that often the output of the computation does not c
Definition: undefined.txt:32
converted
The official guide to swscale for confused that consecutive non overlapping rectangles of slice_bottom special converter These generally are unscaled converters of common like for each output line the vertical scaler pulls lines from a ring buffer When the ring buffer does not contain the wanted then it is pulled from the input slice through the input converter and horizontal scaler The result is also stored in the ring buffer to serve future vertical scaler requests When no more output can be generated because lines from a future slice would be then all remaining lines in the current slice are converted
Definition: swscale.txt:46
mv_scale
static av_always_inline void mv_scale(Mv *dst, const Mv *src, int td, int tb)
Definition: hevc_mvs.c:116
H1
F H1 F F H1 F F F F H1<-F-------F-------F v v v H2 H3 H2 ^ ^ ^ F-------F-------F-> H1<-F-------F-------F|||||||||F H1 F|||||||||F H1 Funavailable fullpel samples(outside the picture for example) shall be equalto the closest available fullpel sampleSmaller pel interpolation:--------------------------if diag_mc is set then points which lie on a line between 2 vertically, horizontally or diagonally adjacent halfpel points shall be interpolatedlinearly with rounding to nearest and halfway values rounded up.points which lie on 2 diagonals at the same time should only use the onediagonal not containing the fullpel point F--> O q O<--h1-> O q O<--F v \/v \/v O O O O O O O|/|\|q q q q q|/|\|O O O O O O O ^/\ ^/\ ^ h2--> O q O<--h3-> O q O<--h2 v \/v \/v O O O O O O O|\|/|q q q q q|\|/|O O O O O O O ^/\ ^/\ ^ F--> O q O<--h1-> O q O<--Fthe remaining points shall be bilinearly interpolated from theup to 4 surrounding halfpel and fullpel points, again rounding should be tonearest and halfway values rounded upcompliant Snow decoders MUST support 1-1/8 pel luma and 1/2-1/16 pel chromainterpolation at leastOverlapped block motion compensation:-------------------------------------FIXMELL band prediction:===================Each sample in the LL0 subband is predicted by the median of the left, top andleft+top-topleft samples, samples outside the subband shall be considered tobe 0. To reverse this prediction in the decoder apply the following.for(y=0;y< height;y++){ for(x=0;x< width;x++){ sample[y][x]+=median(sample[y-1][x], sample[y][x-1], sample[y-1][x]+sample[y][x-1]-sample[y-1][x-1]);}}sample[-1][ *]=sample[ *][-1]=0;width, height here are the width and height of the LL0 subband not of the finalvideoDequantization:===============FIXMEWavelet Transform:==================Snow supports 2 wavelet transforms, the symmetric biorthogonal 5/3 integertransform and an integer approximation of the symmetric biorthogonal 9/7daubechies wavelet.2D IDWT(inverse discrete wavelet transform) --------------------------------------------The 2D IDWT applies a 2D filter recursively, each time combining the4 lowest frequency subbands into a single subband until only 1 subbandremains.The 2D filter is done by first applying a 1D filter in the vertical directionand then applying it in the horizontal one. --------------- --------------- --------------- ---------------|LL0|HL0|||||||||||||---+---|HL1||L0|H0|HL1||LL1|HL1|||||LH0|HH0|||||||||||||-------+-------|-> L1 H1 LH1 HH1 LH1 HH1 LH1 HH1 H1
Definition: snow.txt:554
input_files
InputFile ** input_files
Definition: ffmpeg.c:104
methods
FFmpeg multithreading methods
Definition: multithreading.txt:2
source
these buffered frames must be flushed immediately if a new input produces new the filter must not call request_frame to get more It must just process the frame or queue it The task of requesting more frames is left to the filter s request_frame method or the application If a filter has several the filter must be ready for frames arriving randomly on any input any filter with several inputs will most likely require some kind of queuing mechanism It is perfectly acceptable to have a limited queue and to drop frames when the inputs are too unbalanced request_frame For filters that do not use the this method is called when a frame is wanted on an output For a source
Definition: filter_design.txt:255
http
s EdgeDetect Foobar g libavfilter vf_edgedetect c libavfilter vf_foobar c edit libavfilter and add an entry for foobar following the pattern of the other filters edit libavfilter allfilters and add an entry for foobar following the pattern of the other filters configure make j< whatever > ffmpeg ffmpeg i http
Definition: writing_filters.txt:29
interleave
static void interleave(uint8_t *dst, uint8_t *src, int w, int h, int dst_linesize, int src_linesize, enum FilterMode mode, int swap)
Definition: vf_il.c:110
FF_FILTER_FORWARD_STATUS_ALL
FF_FILTER_FORWARD_STATUS_ALL(outlink, filter)
options
const OptionDef options[]
blur
static void blur(uint8_t *dst, int dst_step, const uint8_t *src, int src_step, int len, int radius, int pixsize)
Definition: vf_boxblur.c:160
H3
vertical horizontal halfpel samples are found by H3[y][x]
Definition: snow.txt:427
init
int(* init)(AVBSFContext *ctx)
Definition: dts2pts.c:366
get_audio_buffer
static AVFrame * get_audio_buffer(AVFilterLink *inlink, int nb_samples)
Definition: avf_concat.c:210
ff_inlink_set_status
void ff_inlink_set_status(AVFilterLink *link, int status)
Set the status on an input link.
Definition: avfilter.c:1577
scroll
static void scroll(AVFilterContext *ctx, AVFrame *in, AVFrame *out)
Definition: vf_scroll.c:103
copy
static void copy(const float *p1, float *p2, const int length)
Definition: vf_vaguedenoiser.c:186
Header
@ Header
Definition: mxfdec.c:74
av_frame_ref
int av_frame_ref(AVFrame *dst, const AVFrame *src)
Set up a new reference to the data described by the source frame.
Definition: frame.c:384
shift
static int shift(int a, int b)
Definition: bonk.c:261
output_files
OutputFile ** output_files
Definition: ffmpeg.c:107
for
for(k=2;k<=8;++k)
Definition: h264pred_template.c:425
sample
#define sample
Definition: flacdsp_template.c:44
size
int size
Definition: twinvq_data.h:10344
section
Definition: ffprobe.c:241
pix_sum
static int pix_sum(const uint8_t *pix, int line_size, int w, int h)
Definition: snowenc.c:306
av_frame_is_writable
int av_frame_is_writable(AVFrame *frame)
Check if the frame data is writable.
Definition: frame.c:645
prediction
static int64_t prediction(int delta, ChannelContext *c)
Definition: misc4.c:78
does
s EdgeDetect Foobar g libavfilter vf_edgedetect c libavfilter vf_foobar c edit libavfilter and add an entry for foobar following the pattern of the other filters edit libavfilter allfilters and add an entry for foobar following the pattern of the other filters configure make j< whatever > ffmpeg ffmpeg i you should get a foobar png with Lena edge detected That s your new playground is ready Some little details about what s going which in turn will define variables for the build system and the and we are assuming vf_foobar is as well We are also assuming vf_foobar is not an edge detector so you can update the boilerplate with your credits Doxy Next chunk is the Doxygen about the file See does
Definition: writing_filters.txt:66
printf
printf("static const uint8_t my_array[100] = {\n")
gray
The official guide to swscale for confused that consecutive non overlapping rectangles of slice_bottom special converter These generally are unscaled converters of common like for each output line the vertical scaler pulls lines from a ring buffer When the ring buffer does not contain the wanted then it is pulled from the input slice through the input converter and horizontal scaler The result is also stored in the ring buffer to serve future vertical scaler requests When no more output can be generated because lines from a future slice would be then all remaining lines in the current slice are horizontally scaled and put in the ring buffer[This is done for luma and chroma, each with possibly different numbers of lines per picture.] Input to YUV Converter When the input to the main path is not planar bits per component YUV or bit gray
Definition: swscale.txt:52
range
enum AVColorRange range
Definition: mediacodec_wrapper.c:2464
AVFilter::description
const char * description
A description of the filter.
Definition: avfilter.h:177
header
static const uint8_t header[24]
Definition: sdr2.c:68
align
static const uint8_t *BS_FUNC() align(BSCTX *bc)
Skip bits to a byte boundary.
Definition: bitstream_template.h:411
split
static char * split(char *message, char delim)
Definition: af_channelmap.c:81
CONFIG_FOOBAR_FILTER
#define CONFIG_FOOBAR_FILTER
encode
static void encode(AVCodecContext *ctx, AVFrame *frame, AVPacket *pkt, FILE *output)
Definition: encode_audio.c:94
height
#define height
a
The reader does not expect b to be semantically here and if the code is changed by maybe adding a a division or other the signedness will almost certainly be mistaken To avoid this confusion a new type was SUINT is the C unsigned type but it holds a signed int to use the same example SUINT a
Definition: undefined.txt:41
H
#define H
Definition: pixlet.c:39
line
Definition: graph2dot.c:48
FF_FILTER_FORWARD_WANTED
FF_FILTER_FORWARD_WANTED(outlink, inlink)
forward
static int forward(AudioFWTDNContext *s, const double *in, int in_length, double **out, int *out_length, int ch, uint64_t sn)
Definition: af_afwtdn.c:620
that
if it could not because there are no more it should return AVERROR_EOF The typical implementation of request_frame for a filter with several inputs will look like that
Definition: filter_design.txt:273
N
#define N
Definition: af_mcompand.c:54
fact
static double fact(double i)
Definition: af_aiir.c:944
version
version
Definition: libkvazaar.c:321
predictor
static void predictor(uint8_t *src, ptrdiff_t size)
Definition: exrenc.c:169
decoders
Decoder ** decoders
Definition: ffmpeg.c:113
input
and forward the test the status of outputs and forward it to the corresponding return FFERROR_NOT_READY If the filters stores internally one or a few frame for some input
Definition: filter_design.txt:172
interpolation
static int interpolation(DeclickChannel *c, const double *src, int ar_order, double *acoefficients, int *index, int nb_errors, double *auxiliary, double *interpolated)
Definition: af_adeclick.c:390
Y
#define Y
Definition: boxblur.h:37
introduced
The reader does not expect b to be semantically here and if the code is changed by maybe adding a a division or other the signedness will almost certainly be mistaken To avoid this confusion a new type was introduced
Definition: undefined.txt:38
XMM_CLOBBERS_ONLY
#define XMM_CLOBBERS_ONLY(...)
Definition: asm.h:99
implementations
the pkt_dts and pkt_pts fields in AVFrame will work as usual Restrictions on codec implementations
Definition: multithreading.txt:29
distribution
This document is a tutorial initiation for writing simple filters in libavfilter libavfilter is which means that it is highly recommended that you submit your filters to the FFmpeg development mailing list and make sure that they are applied your filters are likely to have a very short lifetime due to more or less regular internal API and a limited distribution
Definition: writing_filters.txt:8
AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC
#define AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC
Some filters support a generic "enable" expression option that can be used to enable or disable a fil...
Definition: avfilter.h:147
filesize
static int64_t filesize(AVIOContext *pb)
Definition: ffmpeg_mux.c:51
b
Undefined Behavior In the C some operations are like signed integer dereferencing freed accessing outside allocated Undefined Behavior must not occur in a C it is not safe even if the output of undefined operations is unused The unsafety may seem nit picking but Optimizing compilers have in fact optimized code on the assumption that no undefined Behavior occurs Optimizing code based on wrong assumptions can and has in some cases lead to effects beyond the output of computations The signed integer overflow problem in speed critical code Code which is highly optimized and works with signed integers sometimes has the problem that often the output of the computation does not b
Definition: undefined.txt:32
mail
FFmpeg instead several VMs run on it ffmpeg org mail
Definition: infra.txt:20
layout
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel layout
Definition: filter_design.txt:18
flag
#define flag(name)
Definition: cbs_av1.c:466
tests
const TestCase tests[]
Definition: fifo_muxer.c:367
uninit
static void uninit(AVBSFContext *ctx)
Definition: pcm_rechunk.c:68
Type
Type
Definition: vf_idet.h:29
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:256
code
and forward the test the status of outputs and forward it to the corresponding return FFERROR_NOT_READY If the filters stores internally one or a few frame for some it can consider them to be part of the FIFO and delay acknowledging a status change accordingly Example code
Definition: filter_design.txt:178
LIBAVFILTER_VERSION_MINOR
#define LIBAVFILTER_VERSION_MINOR
Definition: version.h:34
available
if no frame is available
Definition: filter_design.txt:166
Code
One code in hash table.
Definition: lzwenc.c:43
needed
The exact code depends on how similar the blocks are and how related they are to the and needs to apply these operations to the correct inlink or outlink if there are several Macros are available to factor that when no extra processing is needed
Definition: filter_design.txt:212
delta
float delta
Definition: vorbis_enc_data.h:430
ilog2
any process which generates a stream compliant to the syntactical and semantic requirements and which is decodable by the process described in this spec shall be considered a conformant Snow encoder but not strictly required ilog2(x) is the rounded down logarithm of x with basis 2 ilog2(0)=0Type definitions
Definition: snow.txt:23
value
it s the only field you need to keep assuming you have a context There is some magic you don t need to care about around this just let it vf default value
Definition: writing_filters.txt:86
CONFIG_HARDCODED_TABLES
#define CONFIG_HARDCODED_TABLES
Definition: aacps_tablegen_template.c:25
description
it s the only field you need to keep assuming you have a context There is some magic you don t need to care about around this just let it vf description
Definition: writing_filters.txt:86
SUINT
#define SUINT
Definition: dct32_template.c:30
MC
#define MC(PEL, DIR, WIDTH, TAP, DIR1, FILT_DIR)
Definition: hevcdsp_lsx.c:3227
state
static struct @416 state
filter
s EdgeDetect Foobar g libavfilter vf_edgedetect c libavfilter vf_foobar c edit libavfilter and add an entry for foobar following the pattern of the other filters edit libavfilter allfilters and add an entry for foobar following the pattern of the other filters configure make j< whatever > ffmpeg ffmpeg i you should get a foobar png with Lena edge detected That s your new playground is ready Some little details about what s going which in turn will define variables for the build system and the and we are assuming vf_foobar is as well We are also assuming vf_foobar is not an edge detector filter
Definition: writing_filters.txt:60
CONTEXT
#define CONTEXT
Definition: af_asetrate.c:32
headroom
static int headroom(int *la)
Definition: nellymoser.c:106
plain
static const uint8_t plain[]
Definition: aes_ctr.c:25
outputs
static const AVFilterPad outputs[]
Definition: af_aap.c:311
nb_output_files
int nb_output_files
Definition: ffmpeg.c:108
log2
#define log2(x)
Definition: libm.h:404
needed
The official guide to swscale for confused that consecutive non overlapping rectangles of slice_bottom special converter These generally are unscaled converters of common like for each output line the vertical scaler pulls lines from a ring buffer When the ring buffer does not contain the wanted then it is pulled from the input slice through the input converter and horizontal scaler The result is also stored in the ring buffer to serve future vertical scaler requests When no more output can be generated because lines from a future slice would be needed
Definition: swscale.txt:45
stride
#define stride
Definition: h264pred_template.c:537
AVFilter
Filter definition.
Definition: avfilter.h:166
directory
FFmpeg currently uses a custom build this text attempts to document some of its obscure features and options Makefile the full command issued by make and its output will be shown on the screen DBG Preprocess x86 external assembler files to a dbg asm file in the object directory
Definition: build_system.txt:12
language
Undefined Behavior In the C language
Definition: undefined.txt:3
array
static int array[MAX_W *MAX_W]
Definition: jpeg2000dwt.c:111
files
Writing a table generator This documentation is preliminary Parts of the API are not good and should be changed Basic concepts A table generator consists of two files
Definition: tablegen.txt:8
ret
ret
Definition: filter_design.txt:187
AVStream
Stream structure.
Definition: avformat.h:743
pixfmt
enum AVPixelFormat pixfmt
Definition: kmsgrab.c:367
__asm__
__asm__(".macro parse_r var r\n\t" "\\var = -1\n\t" _IFC_REG(0) _IFC_REG(1) _IFC_REG(2) _IFC_REG(3) _IFC_REG(4) _IFC_REG(5) _IFC_REG(6) _IFC_REG(7) _IFC_REG(8) _IFC_REG(9) _IFC_REG(10) _IFC_REG(11) _IFC_REG(12) _IFC_REG(13) _IFC_REG(14) _IFC_REG(15) _IFC_REG(16) _IFC_REG(17) _IFC_REG(18) _IFC_REG(19) _IFC_REG(20) _IFC_REG(21) _IFC_REG(22) _IFC_REG(23) _IFC_REG(24) _IFC_REG(25) _IFC_REG(26) _IFC_REG(27) _IFC_REG(28) _IFC_REG(29) _IFC_REG(30) _IFC_REG(31) ".iflt \\var\n\t" ".error \"Unable to parse register name \\r\"\n\t" ".endif\n\t" ".endm")
pred
static const float pred[4]
Definition: siprdata.h:259
currently
The official guide to swscale for confused that consecutive non overlapping rectangles of slice_bottom special converter These generally are unscaled converters of common like for each output line the vertical scaler pulls lines from a ring buffer When the ring buffer does not contain the wanted then it is pulled from the input slice through the input converter and horizontal scaler The result is also stored in the ring buffer to serve future vertical scaler requests When no more output can be generated because lines from a future slice would be then all remaining lines in the current slice are horizontally scaled and put in the ring buffer[This is done for luma and chroma, each with possibly different numbers of lines per picture.] Input to YUV Converter When the input to the main path is not planar bits per component YUV or bit it is converted to planar bit YUV Two sets of converters exist for this currently
Definition: swscale.txt:54
links
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output links
Definition: filter_design.txt:14
frame
these buffered frames must be flushed immediately if a new input produces new the filter must not call request_frame to get more It must just process the frame or queue it The task of requesting more frames is left to the filter s request_frame method or the application If a filter has several the filter must be ready for frames arriving randomly on any input any filter with several inputs will most likely require some kind of queuing mechanism It is perfectly acceptable to have a limited queue and to drop frames when the inputs are too unbalanced request_frame For filters that do not use the this method is called when a frame is wanted on an output For a it should directly call filter_frame on the corresponding output For a if there are queued frames already one of these frames should be pushed If the filter should request a frame on one of its repeatedly until at least one frame has been pushed Return or at least make progress towards producing a frame
Definition: filter_design.txt:264
comment
static int FUNC() comment(CodedBitstreamContext *ctx, RWContext *rw, JPEGRawComment *current)
Definition: cbs_jpeg_syntax_template.c:174
ff_thread_finish_setup
the pkt_dts and pkt_pts fields in AVFrame will work as usual Restrictions on codec whose streams don t reset across will not work because their bitstreams cannot be decoded in parallel *The contents of buffers must not be read before as well as code calling up to before the decode process starts Call ff_thread_finish_setup() afterwards. If some code can 't be moved
request_frame
static int request_frame(AVFilterLink *outlink)
Definition: af_aecho.c:273
left
Tag MUST be and< 10hcoeff half pel interpolation filter coefficients, hcoeff[0] are the 2 middle coefficients[1] are the next outer ones and so on, resulting in a filter like:...eff[2], hcoeff[1], hcoeff[0], hcoeff[0], hcoeff[1], hcoeff[2] ... the sign of the coefficients is not explicitly stored but alternates after each coeff and coeff[0] is positive, so ...,+,-,+,-,+,+,-,+,-,+,... hcoeff[0] is not explicitly stored but found by subtracting the sum of all stored coefficients with signs from 32 hcoeff[0]=32 - hcoeff[1] - hcoeff[2] - ... a good choice for hcoeff and htaps is htaps=6 hcoeff={40,-10, 2} an alternative which requires more computations at both encoder and decoder side and may or may not be better is htaps=8 hcoeff={42,-14, 6,-2}ref_frames minimum of the number of available reference frames and max_ref_frames for example the first frame after a key frame always has ref_frames=1spatial_decomposition_type wavelet type 0 is a 9/7 symmetric compact integer wavelet 1 is a 5/3 symmetric compact integer wavelet others are reserved stored as delta from last, last is reset to 0 if always_reset||keyframeqlog quality(logarithmic quantizer scale) stored as delta from last, last is reset to 0 if always_reset||keyframemv_scale stored as delta from last, last is reset to 0 if always_reset||keyframe FIXME check that everything works fine if this changes between framesqbias dequantization bias stored as delta from last, last is reset to 0 if always_reset||keyframeblock_max_depth maximum depth of the block tree stored as delta from last, last is reset to 0 if always_reset||keyframequant_table quantization tableHighlevel bitstream structure:==============================--------------------------------------------|Header|--------------------------------------------|------------------------------------|||Block0||||split?||||yes no||||......... intra?||||:Block01 :yes no||||:Block02 :....... ..........||||:Block03 ::y DC ::ref index:||||:Block04 ::cb DC ::motion x :||||......... :cr DC ::motion y :||||....... ..........|||------------------------------------||------------------------------------|||Block1|||...|--------------------------------------------|------------ ------------ ------------|||Y subbands||Cb subbands||Cr subbands||||--- ---||--- ---||--- ---|||||LL0||HL0||||LL0||HL0||||LL0||HL0|||||--- ---||--- ---||--- ---||||--- ---||--- ---||--- ---|||||LH0||HH0||||LH0||HH0||||LH0||HH0|||||--- ---||--- ---||--- ---||||--- ---||--- ---||--- ---|||||HL1||LH1||||HL1||LH1||||HL1||LH1|||||--- ---||--- ---||--- ---||||--- ---||--- ---||--- ---|||||HH1||HL2||||HH1||HL2||||HH1||HL2|||||...||...||...|||------------ ------------ ------------|--------------------------------------------Decoding process:=================------------|||Subbands|------------||||------------|Intra DC||||LL0 subband prediction ------------|\ Dequantization ------------------- \||Reference frames|\ IDWT|------- -------|Motion \|||Frame 0||Frame 1||Compensation . OBMC v -------|------- -------|--------------. \------> Frame n output Frame Frame<----------------------------------/|...|------------------- Range Coder:============Binary Range Coder:------------------- The implemented range coder is an adapted version based upon "Range encoding: an algorithm for removing redundancy from a digitised message." by G. N. N. Martin. The symbols encoded by the Snow range coder are bits(0|1). The associated probabilities are not fix but change depending on the symbol mix seen so far. bit seen|new state ---------+----------------------------------------------- 0|256 - state_transition_table[256 - old_state];1|state_transition_table[old_state];state_transition_table={ 0, 0, 0, 0, 0, 0, 0, 0, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 133, 134, 135, 136, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152, 152, 153, 154, 155, 156, 157, 158, 159, 160, 161, 162, 163, 164, 165, 166, 167, 168, 169, 170, 171, 171, 172, 173, 174, 175, 176, 177, 178, 179, 180, 181, 182, 183, 184, 185, 186, 187, 188, 189, 190, 190, 191, 192, 194, 194, 195, 196, 197, 198, 199, 200, 201, 202, 202, 204, 205, 206, 207, 208, 209, 209, 210, 211, 212, 213, 215, 215, 216, 217, 218, 219, 220, 220, 222, 223, 224, 225, 226, 227, 227, 229, 229, 230, 231, 232, 234, 234, 235, 236, 237, 238, 239, 240, 241, 242, 243, 244, 245, 246, 247, 248, 248, 0, 0, 0, 0, 0, 0, 0};FIXME Range Coding of integers:------------------------- FIXME Neighboring Blocks:===================left and top are set to the respective blocks unless they are outside of the image in which case they are set to the Null block top-left is set to the top left block unless it is outside of the image in which case it is set to the left block if this block has no larger parent block or it is at the left side of its parent block and the top right block is not outside of the image then the top right block is used for top-right else the top-left block is used Null block y, cb, cr are 128 level, ref, mx and my are 0 Motion Vector Prediction:=========================1. the motion vectors of all the neighboring blocks are scaled to compensate for the difference of reference frames scaled_mv=(mv *(256 *(current_reference+1)/(mv.reference+1))+128)> the median of the scaled left
Definition: snow.txt:386
steps
static const int16_t steps[16]
Definition: misc4.c:30
AVCodecContext
main external API structure.
Definition: avcodec.h:445
syntax
static const ParseSyntax syntax[]
Definition: concatdec.c:443
compare
static float compare(const AVFrame *haystack, const AVFrame *obj, int offx, int offy)
Definition: vf_find_rect.c:96
again
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining again
Definition: filter_design.txt:25
if
if(!keyframe)
Definition: snow.txt:61
buffer
the frame and frame reference mechanism is intended to as much as expensive copies of that data while still allowing the filters to produce correct results The data is stored in buffers represented by AVFrame structures Several references can point to the same frame buffer
Definition: filter_design.txt:49
get_buffer
the pkt_dts and pkt_pts fields in AVFrame will work as usual Restrictions on codec whose streams don t reset across will not work because their bitstreams cannot be decoded in parallel *The contents of buffers must not be read before as well as code calling get_buffer()
Compensation
Motion Compensation
Definition: snow.txt:418
Transform
Definition: vf_deshake.c:81
headers
FFmpeg currently uses a custom build this text attempts to document some of its obscure features and options Makefile the full command issued by make and its output will be shown on the screen DBG Preprocess x86 external assembler files to a dbg asm file in the object which then gets compiled Helps in developing those assembler files DESTDIR Destination directory for the install useful to prepare packages or install FFmpeg in cross environments GEN Set to ‘1’ to generate the missing or mismatched references Makefile builds all the libraries and the executables fate Run the fate test note that you must have installed it fate list List all fate regression test targets install Install headers
Definition: build_system.txt:34
CC
#define CC
update_thread_context
the pkt_dts and pkt_pts fields in AVFrame will work as usual Restrictions on codec whose streams don t reset across will not work because their bitstreams cannot be decoded in parallel *The contents of buffers must not be read before as well as code calling up to before the decode process starts Call have update_thread_context() run it in the next thread. Add AV_CODEC_CAP_FRAME_THREADS to the codec capabilities. There will be very little speed gain at this point but it should work. Use ff_thread_get_buffer()(or ff_progress_frame_get_buffer() in case you have inter-frame dependencies and use the ProgressFrame API) to allocate frame buffers. Call ff_progress_frame_report() after some part of the current picture has decoded. A good place to put this is where draw_horiz_band() is called - add this if it isn 't called anywhere
video
A Quick Description Of Rate Distortion Theory We want to encode a video
Definition: rate_distortion.txt:3
test
static void test(const char *pattern, const char *host)
Definition: noproxy.c:23
swscale
static int swscale(SwsContext *c, const uint8_t *src[], int srcStride[], int srcSliceY, int srcSliceH, uint8_t *dst[], int dstStride[], int dstSliceY, int dstSliceH)
Definition: swscale.c:236
values
these buffered frames must be flushed immediately if a new input produces new the filter must not call request_frame to get more It must just process the frame or queue it The task of requesting more frames is left to the filter s request_frame method or the application If a filter has several the filter must be ready for frames arriving randomly on any input any filter with several inputs will most likely require some kind of queuing mechanism It is perfectly acceptable to have a limited queue and to drop frames when the inputs are too unbalanced request_frame For filters that do not use the this method is called when a frame is wanted on an output For a it should directly call filter_frame on the corresponding output For a if there are queued frames already one of these frames should be pushed If the filter should request a frame on one of its repeatedly until at least one frame has been pushed Return values
Definition: filter_design.txt:263
ref
static int ref[MAX_W *MAX_W]
Definition: jpeg2000dwt.c:112
L
#define L(x)
Definition: vpx_arith.h:36
samples
Filter the word “frame” indicates either a video frame or a group of audio samples
Definition: filter_design.txt:8
mean
static float mean(const float *input, int size)
Definition: vf_nnedi.c:863
note
F H1 F F H1 F F F F H1<-F-------F-------F v v v H2 H3 H2 ^ ^ ^ F-------F-------F-> H1<-F-------F-------F|||||||||F H1 F|||||||||F H1 Funavailable fullpel samples(outside the picture for example) shall be equalto the closest available fullpel sampleSmaller pel interpolation:--------------------------if diag_mc is set then points which lie on a line between 2 vertically, horizontally or diagonally adjacent halfpel points shall be interpolatedlinearly with rounding to nearest and halfway values rounded up.points which lie on 2 diagonals at the same time should only use the onediagonal not containing the fullpel point F--> O q O<--h1-> O q O<--F v \/v \/v O O O O O O O|/|\|q q q q q|/|\|O O O O O O O ^/\ ^/\ ^ h2--> O q O<--h3-> O q O<--h2 v \/v \/v O O O O O O O|\|/|q q q q q|\|/|O O O O O O O ^/\ ^/\ ^ F--> O q O<--h1-> O q O<--Fthe remaining points shall be bilinearly interpolated from theup to 4 surrounding halfpel and fullpel points, again rounding should be tonearest and halfway values rounded upcompliant Snow decoders MUST support 1-1/8 pel luma and 1/2-1/16 pel chromainterpolation at leastOverlapped block motion compensation:-------------------------------------FIXMELL band prediction:===================Each sample in the LL0 subband is predicted by the median of the left, top andleft+top-topleft samples, samples outside the subband shall be considered tobe 0. To reverse this prediction in the decoder apply the following.for(y=0;y< height;y++){ for(x=0;x< width;x++){ sample[y][x]+=median(sample[y-1][x], sample[y][x-1], sample[y-1][x]+sample[y][x-1]-sample[y-1][x-1]);}}sample[-1][ *]=sample[ *][-1]=0;width, height here are the width and height of the LL0 subband not of the finalvideoDequantization:===============FIXMEWavelet Transform:==================Snow supports 2 wavelet transforms, the symmetric biorthogonal 5/3 integertransform and an integer approximation of the symmetric biorthogonal 9/7daubechies wavelet.2D IDWT(inverse discrete wavelet transform) --------------------------------------------The 2D IDWT applies a 2D filter recursively, each time combining the4 lowest frequency subbands into a single subband until only 1 subbandremains.The 2D filter is done by first applying a 1D filter in the vertical directionand then applying it in the horizontal one. --------------- --------------- --------------- ---------------|LL0|HL0|||||||||||||---+---|HL1||L0|H0|HL1||LL1|HL1|||||LH0|HH0|||||||||||||-------+-------|-> L1 H1 LH1 HH1 LH1 HH1 LH1 HH1 note
Definition: snow.txt:555
G
#define G
Definition: huffyuv.h:43
IDCT
#define IDCT(H)
Definition: hevcdsp_template.c:242
ff_outlink_get_status
int ff_outlink_get_status(AVFilterLink *link)
Get the status on an output link.
Definition: avfilter.c:1593
AVFilterContext
An instance of a filter.
Definition: avfilter.h:407
need
s EdgeDetect Foobar g libavfilter vf_edgedetect c libavfilter vf_foobar c edit libavfilter and add an entry for foobar following the pattern of the other filters edit libavfilter allfilters and add an entry for foobar following the pattern of the other filters configure make j< whatever > ffmpeg ffmpeg i you should get a foobar png with Lena edge detected That s your new playground is ready Some little details about what s going which in turn will define variables for the build system and the and we are assuming vf_foobar is as well We are also assuming vf_foobar is not an edge detector so you can update the boilerplate with your credits Doxy Next chunk is the Doxygen about the file See and add some references if you feel like it Context Skip the headers and scroll down to the definition of FoobarContext This is your state context It is already filled with when you get it so do not worry about uninitialized reads into this context This is where you put all global information that you need
Definition: writing_filters.txt:75
factor
static const int factor[16]
Definition: vf_pp7.c:79
timeline
Definition: dashdec.c:48
https
s EdgeDetect Foobar g libavfilter vf_edgedetect c libavfilter vf_foobar c edit libavfilter and add an entry for foobar following the pattern of the other filters edit libavfilter allfilters and add an entry for foobar following the pattern of the other filters configure make j< whatever > ffmpeg ffmpeg i you should get a foobar png with Lena edge detected That s your new playground is ready Some little details about what s going which in turn will define variables for the build system and the and we are assuming vf_foobar is as well We are also assuming vf_foobar is not an edge detector so you can update the boilerplate with your credits Doxy Next chunk is the Doxygen about the file See https
Definition: writing_filters.txt:66
bad
static int bad(InterplayACMContext *s, unsigned ind, unsigned col)
Definition: interplayacm.c:130
https
FFmpeg instead several VMs run on it ffmpeg org and public facing also website git fftrac this part is build by a cronjob So is the doxygen stuff as well as the FFmpeg git snapshot These scripts are under the ffcron user https
Definition: infra.txt:85
review
This document is a tutorial initiation for writing simple filters in libavfilter libavfilter is which means that it is highly recommended that you submit your filters to the FFmpeg development mailing list and make sure that they are applied your filters are likely to have a very short lifetime due to more or less regular internal API and a limited review
Definition: writing_filters.txt:8
overflow
Undefined Behavior In the C some operations are like signed integer overflow
Definition: undefined.txt:3
L3
F H1 F F H1 F F F F H1<-F-------F-------F v v v H2 H3 H2 ^ ^ ^ F-------F-------F-> H1<-F-------F-------F|||||||||F H1 F|||||||||F H1 Funavailable fullpel samples(outside the picture for example) shall be equalto the closest available fullpel sampleSmaller pel interpolation:--------------------------if diag_mc is set then points which lie on a line between 2 vertically, horizontally or diagonally adjacent halfpel points shall be interpolatedlinearly with rounding to nearest and halfway values rounded up.points which lie on 2 diagonals at the same time should only use the onediagonal not containing the fullpel point F--> O q O<--h1-> O q O<--F v \/v \/v O O O O O O O|/|\|q q q q q|/|\|O O O O O O O ^/\ ^/\ ^ h2--> O q O<--h3-> O q O<--h2 v \/v \/v O O O O O O O|\|/|q q q q q|\|/|O O O O O O O ^/\ ^/\ ^ F--> O q O<--h1-> O q O<--Fthe remaining points shall be bilinearly interpolated from theup to 4 surrounding halfpel and fullpel points, again rounding should be tonearest and halfway values rounded upcompliant Snow decoders MUST support 1-1/8 pel luma and 1/2-1/16 pel chromainterpolation at leastOverlapped block motion compensation:-------------------------------------FIXMELL band prediction:===================Each sample in the LL0 subband is predicted by the median of the left, top andleft+top-topleft samples, samples outside the subband shall be considered tobe 0. To reverse this prediction in the decoder apply the following.for(y=0;y< height;y++){ for(x=0;x< width;x++){ sample[y][x]+=median(sample[y-1][x], sample[y][x-1], sample[y-1][x]+sample[y][x-1]-sample[y-1][x-1]);}}sample[-1][ *]=sample[ *][-1]=0;width, height here are the width and height of the LL0 subband not of the finalvideoDequantization:===============FIXMEWavelet Transform:==================Snow supports 2 wavelet transforms, the symmetric biorthogonal 5/3 integertransform and an integer approximation of the symmetric biorthogonal 9/7daubechies wavelet.2D IDWT(inverse discrete wavelet transform) --------------------------------------------The 2D IDWT applies a 2D filter recursively, each time combining the4 lowest frequency subbands into a single subband until only 1 subbandremains.The 2D filter is done by first applying a 1D filter in the vertical directionand then applying it in the horizontal one. --------------- --------------- --------------- ---------------|LL0|HL0|||||||||||||---+---|HL1||L0|H0|HL1||LL1|HL1|||||LH0|HH0|||||||||||||-------+-------|-> L1 H1 LH1 HH1 LH1 HH1 LH1 HH1 L3
Definition: snow.txt:554
it
s EdgeDetect Foobar g libavfilter vf_edgedetect c libavfilter vf_foobar c edit libavfilter and add an entry for foobar following the pattern of the other filters edit libavfilter allfilters and add an entry for foobar following the pattern of the other filters configure make j< whatever > ffmpeg ffmpeg i you should get a foobar png with Lena edge detected That s it
Definition: writing_filters.txt:31
project
static float project(float origin_x, float origin_y, float dest_x, float dest_y, float point_x, float point_y, int type)
Definition: vsrc_gradients.c:203
scale
static void scale(int *out, const int *in, const int w, const int h, const int shift)
Definition: intra.c:291
ProgressFrame
The ProgressFrame structure.
Definition: progressframe.h:73
FF_FILTER_FORWARD_STATUS
FF_FILTER_FORWARD_STATUS(inlink, outlink)
equal
static int equal(MetadataContext *s, const char *value1, const char *value2)
Definition: f_metadata.c:143
cr
static double cr(void *priv, double x, double y)
Definition: vf_geq.c:247
status_in
the definition of that something depends on the semantic of the filter The callback must examine the status of the filter s links and proceed accordingly The status of output links is stored in the status_in and status_out fields and tested by the then the processing requires a frame on this link and the filter is expected to make efforts in that direction The status of input links is stored by the status_in
Definition: filter_design.txt:154
avoid
the frame and frame reference mechanism is intended to avoid
Definition: filter_design.txt:45
src
INIT_CLIP pixel * src
Definition: h264pred_template.c:418
ready
these buffered frames must be flushed immediately if a new input produces new the filter must not call request_frame to get more It must just process the frame or queue it The task of requesting more frames is left to the filter s request_frame method or the application If a filter has several the filter must be ready for frames arriving randomly on any input any filter with several inputs will most likely require some kind of queuing mechanism It is perfectly acceptable to have a limited queue and to drop frames when the inputs are too unbalanced request_frame For filters that do not use the this method is called when a frame is wanted on an output For a it should directly call filter_frame on the corresponding output For a if there are queued frames already ready
Definition: filter_design.txt:258
query_formats
static int query_formats(AVFilterContext *ctx)
Definition: aeval.c:246
OutputStream
Definition: mux.c:53
coeff
static const double coeff[2][5]
Definition: vf_owdenoise.c:80
block
The exact code depends on how similar the blocks are and how related they are to the block
Definition: filter_design.txt:207
av_log
#define av_log(a,...)
Definition: tableprint_vlc.h:27
sse
static int sse(MpegEncContext *s, const uint8_t *src1, const uint8_t *src2, int w, int h, int stride)
Definition: mpegvideo_enc.c:2636
h
h
Definition: vp9dsp_template.c:2038
ff_outlink_frame_wanted
the definition of that something depends on the semantic of the filter The callback must examine the status of the filter s links and proceed accordingly The status of output links is stored in the status_in and status_out fields and tested by the ff_outlink_frame_wanted() function. If this function returns true
Sequence
@ Sequence
Definition: mxf.h:38
dimension
The official guide to swscale for confused that consecutive non overlapping rectangles of dimension(0, slice_top) -(picture_width
diff_bytes
static void diff_bytes(HYuvEncContext *s, uint8_t *dst, const uint8_t *src0, const uint8_t *src1, int w)
Definition: huffyuvenc.c:81
Otherwise
This document is a tutorial initiation for writing simple filters in libavfilter libavfilter is which means that it is highly recommended that you submit your filters to the FFmpeg development mailing list and make sure that they are applied Otherwise
Definition: writing_filters.txt:6
monolithic
This document is a tutorial initiation for writing simple filters in libavfilter libavfilter is monolithic
Definition: writing_filters.txt:4
main
int main(int argc, char **argv)
Definition: bin2c.c:26
MpegEncContext
MpegEncContext.
Definition: mpegvideo.h:73
filter
F H1 F F H1 F F F F H1<-F-------F-------F v v v H2 H3 H2 ^ ^ ^ F-------F-------F-> H1<-F-------F-------F|||||||||F H1 F|||||||||F H1 Funavailable fullpel samples(outside the picture for example) shall be equalto the closest available fullpel sampleSmaller pel interpolation:--------------------------if diag_mc is set then points which lie on a line between 2 vertically, horizontally or diagonally adjacent halfpel points shall be interpolatedlinearly with rounding to nearest and halfway values rounded up.points which lie on 2 diagonals at the same time should only use the onediagonal not containing the fullpel point F--> O q O<--h1-> O q O<--F v \/v \/v O O O O O O O|/|\|q q q q q|/|\|O O O O O O O ^/\ ^/\ ^ h2--> O q O<--h3-> O q O<--h2 v \/v \/v O O O O O O O|\|/|q q q q q|\|/|O O O O O O O ^/\ ^/\ ^ F--> O q O<--h1-> O q O<--Fthe remaining points shall be bilinearly interpolated from theup to 4 surrounding halfpel and fullpel points, again rounding should be tonearest and halfway values rounded upcompliant Snow decoders MUST support 1-1/8 pel luma and 1/2-1/16 pel chromainterpolation at leastOverlapped block motion compensation:-------------------------------------FIXMELL band prediction:===================Each sample in the LL0 subband is predicted by the median of the left, top andleft+top-topleft samples, samples outside the subband shall be considered tobe 0. To reverse this prediction in the decoder apply the following.for(y=0;y< height;y++){ for(x=0;x< width;x++){ sample[y][x]+=median(sample[y-1][x], sample[y][x-1], sample[y-1][x]+sample[y][x-1]-sample[y-1][x-1]);}}sample[-1][ *]=sample[ *][-1]=0;width, height here are the width and height of the LL0 subband not of the finalvideoDequantization:===============FIXMEWavelet Transform:==================Snow supports 2 wavelet transforms, the symmetric biorthogonal 5/3 integertransform and an integer approximation of the symmetric biorthogonal 9/7daubechies wavelet.2D IDWT(inverse discrete wavelet transform) --------------------------------------------The 2D IDWT applies a 2D filter recursively, each time combining the4 lowest frequency subbands into a single subband until only 1 subbandremains.The 2D filter is done by first applying a 1D filter in the vertical directionand then applying it in the horizontal one. --------------- --------------- --------------- ---------------|LL0|HL0|||||||||||||---+---|HL1||L0|H0|HL1||LL1|HL1|||||LH0|HH0|||||||||||||-------+-------|-> L1 H1 LH1 HH1 LH1 HH1 LH1 HH1 this can end with a L or a the number of elements shall be w s[-1] shall be considered equivalent to s[1] s[w] shall be considered equivalent to s[w-2] perform the lifting steps in order as described below Integer filter
Definition: snow.txt:562
sanitize
static void sanitize(uint8_t *line)
Definition: log.c:247
do
it s the only field you need to keep assuming you have a context There is some magic you don t need to care about around this just let it vf default minimum maximum flags name is the option keep it simple and lowercase description are in without and describe what they do
Definition: writing_filters.txt:90
passed
static int passed(HysteresisContext *s, int x, int y, int w)
Definition: vf_hysteresis.c:135
get_video_buffer
static AVFrame * get_video_buffer(AVFilterLink *inlink, int w, int h)
Definition: avf_concat.c:201
Therefore
these buffered frames must be flushed immediately if a new input produces new the filter must not call request_frame to get more It must just process the frame or queue it The task of requesting more frames is left to the filter s request_frame method or the application If a filter has several the filter must be ready for frames arriving randomly on any input Therefore
Definition: filter_design.txt:244
undefined
Undefined Behavior In the C some operations are undefined
Definition: undefined.txt:3
channel
channel
Definition: ebur128.h:39
read
static uint32_t BS_FUNC() read(BSCTX *bc, unsigned int n)
Return n bits from the buffer, n has to be in the 0-32 range.
Definition: bitstream_template.h:231
foobar
it s the only field you need to keep assuming you have a context There is some magic you don t need to care about around this just let it vf foobar
Definition: writing_filters.txt:84
OutputFile
Definition: ffmpeg.h:613
GEN
#define GEN(table)
dither
static const uint8_t dither[8][8]
Definition: vf_fspp.c:61