FFmpeg
vmixdec.c
Go to the documentation of this file.
1 /*
2  * vMix decoder
3  * Copyright (c) 2023 Paul B Mahol
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 #include <stdio.h>
23 #include <stdlib.h>
24 #include <string.h>
25 
26 #include "libavutil/intreadwrite.h"
27 #include "libavutil/mem.h"
28 #include "libavutil/mem_internal.h"
29 
30 #include "avcodec.h"
31 #include "codec_internal.h"
32 #define CACHED_BITSTREAM_READER !ARCH_X86_32
33 #include "golomb.h"
34 #include "get_bits.h"
35 #include "idctdsp.h"
36 #include "thread.h"
37 
38 typedef struct SliceContext {
39  const uint8_t *dc_ptr;
40  const uint8_t *ac_ptr;
41  unsigned dc_size;
42  unsigned ac_size;
43 } SliceContext;
44 
45 typedef struct VMIXContext {
46  int nb_slices;
47  int lshift;
48 
49  int16_t factors[64];
50  uint8_t scan[64];
51 
53  unsigned int slices_size;
54 
56 } VMIXContext;
57 
58 static const uint8_t quality[] = {
59  1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
60  1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
61  1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
62  1, 1, 1, 1, 1, 1,64,63,62,61,
63  60,59,58,57,56,55,54,53,52,51,
64  50,49,48,47,46,45,44,43,42,41,
65  40,39,38,37,36,35,34,33,32,31,
66  30,29,28,27,26,25,24,23,22,21,
67  20,19,18,17,16,15,14,13,12,11,
68  10, 9, 8, 7, 6, 5, 4, 3, 2, 1,
69 };
70 
71 static const uint8_t quant[64] = {
72  16, 16, 19, 22, 22, 26, 26, 27,
73  16, 16, 22, 22, 26, 27, 27, 29,
74  19, 22, 26, 26, 27, 29, 29, 35,
75  22, 24, 27, 27, 29, 32, 34, 38,
76  26, 27, 29, 29, 32, 35, 38, 46,
77  27, 29, 34, 34, 35, 40, 46, 56,
78  29, 34, 34, 37, 40, 48, 56, 69,
79  34, 37, 38, 40, 48, 58, 69, 83,
80 };
81 
83 {
84  VMIXContext *s = avctx->priv_data;
85 
86  avctx->bits_per_raw_sample = 8;
87  avctx->pix_fmt = AV_PIX_FMT_YUV422P;
88 
89  avctx->coded_width = FFALIGN(avctx->width, 16);
90  avctx->coded_height = FFALIGN(avctx->height, 16);
91 
92  ff_idctdsp_init(&s->idsp, avctx);
94  s->idsp.idct_permutation);
95  return 0;
96 }
97 
98 static inline int get_se_golomb_vmix(GetBitContext *gb)
99 {
100  unsigned int buf = get_ue_golomb_long(gb);
101  int sign = (buf & 1) - 1;
102  return ((buf >> 1) ^ (~sign));
103 }
104 
105 static int decode_dcac(AVCodecContext *avctx,
106  GetBitContext *dc_gb, GetBitContext *ac_gb,
107  unsigned *dcrun, unsigned *acrun,
108  AVFrame *frame, int width, int by, int plane)
109 {
110  const ptrdiff_t linesize = frame->linesize[plane];
111  uint8_t *dst = frame->data[plane] + by * linesize;
112  unsigned dc_run = *dcrun, ac_run = *acrun;
113  LOCAL_ALIGNED_32(int16_t, block, [64]);
114  VMIXContext *s = avctx->priv_data;
115  const int16_t *factors = s->factors;
116  const uint8_t *scan = s->scan;
117  const int add = plane ? 0 : 1024;
118  int i, dc_v = 0, ac_v = 0, dc = 0;
119  const int lshift = s->lshift;
120 
121  for (int y = 0; y < 2; y++) {
122  for (int x = 0; x < width; x += 8) {
123  memset(block, 0, sizeof(*block)*64);
124 
125  if (dc_run > 0) {
126  dc_run--;
127  } else {
128  if (get_bits_left(dc_gb) < 1)
129  return AVERROR_INVALIDDATA;
130  dc_v = get_se_golomb_vmix(dc_gb);
131  dc += (unsigned)dc_v;
132  if (!dc_v)
133  dc_run = get_ue_golomb_long(dc_gb);
134  }
135 
136  for (int n = 0; n < 64; n++) {
137  if (ac_run > 0) {
138  ac_run--;
139  continue;
140  }
141 
142  if (get_bits_left(ac_gb) < 1)
143  return AVERROR_INVALIDDATA;
144  ac_v = get_se_golomb_vmix(ac_gb);
145  i = scan[n];
146  block[i] = ((unsigned)ac_v * factors[i]) >> 4;
147  if (!ac_v)
148  ac_run = get_ue_golomb_long(ac_gb);
149  }
150 
151  block[0] = ((unsigned)dc << lshift) + (unsigned)add;
152  s->idsp.idct_put(dst + x, linesize, block);
153  }
154 
155  dst += 8 * linesize;
156  }
157 
158  *dcrun = dc_run;
159  *acrun = ac_run;
160 
161  return 0;
162 }
163 
165  const uint8_t *dc_src, unsigned dc_slice_size,
166  const uint8_t *ac_src, unsigned ac_slice_size,
167  int by)
168 {
169  unsigned dc_run = 0, ac_run = 0;
170  GetBitContext dc_gb, ac_gb;
171  int ret;
172 
173  ret = init_get_bits8(&dc_gb, dc_src, dc_slice_size);
174  if (ret < 0)
175  return ret;
176 
177  ret = init_get_bits8(&ac_gb, ac_src, ac_slice_size);
178  if (ret < 0)
179  return ret;
180 
181  for (int p = 0; p < 3; p++) {
182  const int rshift = !!p;
183  ret = decode_dcac(avctx, &dc_gb, &ac_gb,
184  &dc_run, &ac_run, frame,
185  frame->width >> rshift, by, p);
186  if (ret < 0)
187  return ret;
188 
189  if (get_bits_left(&dc_gb) < 0)
190  return AVERROR_INVALIDDATA;
191  if (get_bits_left(&ac_gb) < 0)
192  return AVERROR_INVALIDDATA;
193 
194  align_get_bits(&dc_gb);
195  align_get_bits(&ac_gb);
196  }
197 
198  if (get_bits_left(&dc_gb) > 0)
199  return AVERROR_INVALIDDATA;
200  if (get_bits_left(&ac_gb) > 0)
201  return AVERROR_INVALIDDATA;
202 
203  return 0;
204 }
205 
206 static int decode_slices(AVCodecContext *avctx, void *arg,
207  int n, int thread_nb)
208 {
209  VMIXContext *s = avctx->priv_data;
210  const uint8_t *dc_slice_ptr = s->slices[n].dc_ptr;
211  const uint8_t *ac_slice_ptr = s->slices[n].ac_ptr;
212  unsigned dc_slice_size = s->slices[n].dc_size;
213  unsigned ac_slice_size = s->slices[n].ac_size;
214  AVFrame *frame = arg;
215 
216  return decode_slice(avctx, frame, dc_slice_ptr, dc_slice_size,
217  ac_slice_ptr, ac_slice_size, n * 16);
218 }
219 
220 static int decode_frame(AVCodecContext *avctx,
221  AVFrame *frame, int *got_frame,
222  AVPacket *avpkt)
223 {
224  VMIXContext *s = avctx->priv_data;
225  unsigned offset, q;
226  int ret;
227 
228  if (avpkt->size <= 7)
229  return AVERROR_INVALIDDATA;
230 
231  s->lshift = 0;
232  offset = 2 + avpkt->data[0];
233  if (offset == 5)
234  s->lshift = avpkt->data[1];
235  else if (offset != 3)
236  return AVERROR_INVALIDDATA;
237 
238  if (s->lshift > 31)
239  return AVERROR_INVALIDDATA;
240 
241  q = quality[FFMIN(avpkt->data[offset - 2], FF_ARRAY_ELEMS(quality)-1)];
242  for (int n = 0; n < 64; n++)
243  s->factors[n] = quant[n] * q;
244 
245  s->nb_slices = (avctx->height + 15) / 16;
246  av_fast_mallocz(&s->slices, &s->slices_size, s->nb_slices * sizeof(*s->slices));
247  if (!s->slices)
248  return AVERROR(ENOMEM);
249 
250  for (int n = 0; n < s->nb_slices; n++) {
251  unsigned slice_size;
252 
253  if (offset + 4 > avpkt->size)
254  return AVERROR_INVALIDDATA;
255 
256  slice_size = AV_RL32(avpkt->data + offset);
257  if (slice_size > avpkt->size)
258  return AVERROR_INVALIDDATA;
259 
260  if (avpkt->size - slice_size - 4LL < offset)
261  return AVERROR_INVALIDDATA;
262 
263  s->slices[n].dc_size = slice_size;
264  s->slices[n].dc_ptr = avpkt->data + offset + 4;
265  offset += slice_size + 4;
266  }
267 
268  for (int n = 0; n < s->nb_slices; n++) {
269  unsigned slice_size;
270 
271  if (offset + 4 > avpkt->size)
272  return AVERROR_INVALIDDATA;
273 
274  slice_size = AV_RL32(avpkt->data + offset);
275  if (slice_size > avpkt->size)
276  return AVERROR_INVALIDDATA;
277 
278  if (avpkt->size - slice_size - 4LL < offset)
279  return AVERROR_INVALIDDATA;
280 
281  s->slices[n].ac_size = slice_size;
282  s->slices[n].ac_ptr = avpkt->data + offset + 4;
283  offset += slice_size + 4;
284  }
285 
286  ret = ff_thread_get_buffer(avctx, frame, 0);
287  if (ret < 0)
288  return ret;
289 
290  avctx->execute2(avctx, decode_slices, frame, NULL, s->nb_slices);
291 
292  *got_frame = 1;
293 
294  return avpkt->size;
295 }
296 
298 {
299  VMIXContext *s = avctx->priv_data;
300  av_freep(&s->slices);
301  return 0;
302 }
303 
305  .p.name = "vmix",
306  CODEC_LONG_NAME("vMix Video"),
307  .p.type = AVMEDIA_TYPE_VIDEO,
308  .p.id = AV_CODEC_ID_VMIX,
309  .priv_data_size = sizeof(VMIXContext),
310  .init = decode_init,
311  .close = decode_end,
313  .p.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_FRAME_THREADS |
315 };
VMIXContext::factors
int16_t factors[64]
Definition: vmixdec.c:49
decode_slice
static int decode_slice(AVCodecContext *avctx, AVFrame *frame, const uint8_t *dc_src, unsigned dc_slice_size, const uint8_t *ac_src, unsigned ac_slice_size, int by)
Definition: vmixdec.c:164
get_bits_left
static int get_bits_left(GetBitContext *gb)
Definition: get_bits.h:695
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
SliceContext::ac_size
unsigned ac_size
Definition: vmixdec.c:42
mem_internal.h
decode_end
static av_cold int decode_end(AVCodecContext *avctx)
Definition: vmixdec.c:297
SliceContext::ac_ptr
const uint8_t * ac_ptr
Definition: vmixdec.c:40
decode_dcac
static int decode_dcac(AVCodecContext *avctx, GetBitContext *dc_gb, GetBitContext *ac_gb, unsigned *dcrun, unsigned *acrun, AVFrame *frame, int width, int by, int plane)
Definition: vmixdec.c:105
AVFrame
This structure describes decoded (raw) audio or video data.
Definition: frame.h:374
VMIXContext::idsp
IDCTDSPContext idsp
Definition: vmixdec.c:55
VMIXContext::slices
SliceContext * slices
Definition: vmixdec.c:52
AVPacket::data
uint8_t * data
Definition: packet.h:524
FFCodec
Definition: codec_internal.h:126
thread.h
ff_idctdsp_init
av_cold void ff_idctdsp_init(IDCTDSPContext *c, AVCodecContext *avctx)
Definition: idctdsp.c:228
golomb.h
exp golomb vlc stuff
ff_permute_scantable
av_cold void ff_permute_scantable(uint8_t dst[64], const uint8_t src[64], const uint8_t permutation[64])
Definition: idctdsp.c:30
FFCodec::p
AVCodec p
The public AVCodec.
Definition: codec_internal.h:130
GetBitContext
Definition: get_bits.h:108
AVCodecContext::coded_height
int coded_height
Definition: avcodec.h:633
AV_CODEC_ID_VMIX
@ AV_CODEC_ID_VMIX
Definition: codec_id.h:323
SliceContext::dc_size
unsigned dc_size
Definition: vmixdec.c:41
quant
static const uint8_t quant[64]
Definition: vmixdec.c:71
FF_ARRAY_ELEMS
#define FF_ARRAY_ELEMS(a)
Definition: sinewin_tablegen.c:29
av_cold
#define av_cold
Definition: attributes.h:90
init_get_bits8
static int init_get_bits8(GetBitContext *s, const uint8_t *buffer, int byte_size)
Initialize GetBitContext.
Definition: get_bits.h:545
width
#define width
FF_CODEC_DECODE_CB
#define FF_CODEC_DECODE_CB(func)
Definition: codec_internal.h:286
intreadwrite.h
s
#define s(width, name)
Definition: cbs_vp9.c:198
decode_frame
static int decode_frame(AVCodecContext *avctx, AVFrame *frame, int *got_frame, AVPacket *avpkt)
Definition: vmixdec.c:220
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
AVCodecContext::bits_per_raw_sample
int bits_per_raw_sample
Bits per sample/pixel of internal libavcodec pixel/sample format.
Definition: avcodec.h:1575
get_se_golomb_vmix
static int get_se_golomb_vmix(GetBitContext *gb)
Definition: vmixdec.c:98
get_bits.h
CODEC_LONG_NAME
#define CODEC_LONG_NAME(str)
Definition: codec_internal.h:271
arg
const char * arg
Definition: jacosubdec.c:67
AV_CODEC_CAP_FRAME_THREADS
#define AV_CODEC_CAP_FRAME_THREADS
Codec supports frame-level multithreading.
Definition: codec.h:110
NULL
#define NULL
Definition: coverity.c:32
LOCAL_ALIGNED_32
#define LOCAL_ALIGNED_32(t, v,...)
Definition: mem_internal.h:156
av_fast_mallocz
void av_fast_mallocz(void *ptr, unsigned int *size, size_t min_size)
Allocate and clear a buffer, reusing the given one if large enough.
Definition: mem.c:562
quality
static const uint8_t quality[]
Definition: vmixdec.c:58
SliceContext
Definition: mss12.h:70
decode_init
static av_cold int decode_init(AVCodecContext *avctx)
Definition: vmixdec.c:82
init
int(* init)(AVBSFContext *ctx)
Definition: dts2pts.c:366
AV_CODEC_CAP_DR1
#define AV_CODEC_CAP_DR1
Codec uses get_buffer() or get_encode_buffer() for allocating buffers and supports custom allocators.
Definition: codec.h:52
AVPacket::size
int size
Definition: packet.h:525
dc
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 top and top right vectors is used as motion vector prediction the used motion vector is the sum of the predictor and(mvx_diff, mvy_diff) *mv_scale Intra DC Prediction block[y][x] dc[1]
Definition: snow.txt:400
codec_internal.h
AV_CODEC_CAP_SLICE_THREADS
#define AV_CODEC_CAP_SLICE_THREADS
Codec supports slice-based (or partition-based) multithreading.
Definition: codec.h:114
offset
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 offset
Definition: writing_filters.txt:86
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:256
FFMIN
#define FFMIN(a, b)
Definition: macros.h:49
AVCodec::name
const char * name
Name of the codec implementation.
Definition: codec.h:194
VMIXContext::nb_slices
int nb_slices
Definition: vmixdec.c:46
VMIXContext
Definition: vmixdec.c:45
AVCodecContext::height
int height
Definition: avcodec.h:618
AVCodecContext::pix_fmt
enum AVPixelFormat pix_fmt
Pixel format, see AV_PIX_FMT_xxx.
Definition: avcodec.h:657
idctdsp.h
avcodec.h
ff_zigzag_direct
const uint8_t ff_zigzag_direct[64]
Definition: mathtables.c:98
ret
ret
Definition: filter_design.txt:187
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
VMIXContext::slices_size
unsigned int slices_size
Definition: vmixdec.c:53
align_get_bits
static const uint8_t * align_get_bits(GetBitContext *s)
Definition: get_bits.h:561
IDCTDSPContext
Definition: idctdsp.h:43
AV_RL32
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_RL32
Definition: bytestream.h:92
AVCodecContext
main external API structure.
Definition: avcodec.h:445
VMIXContext::lshift
int lshift
Definition: vmixdec.c:47
AVCodecContext::coded_width
int coded_width
Bitstream width / height, may be different from width/height e.g.
Definition: avcodec.h:633
AVMEDIA_TYPE_VIDEO
@ AVMEDIA_TYPE_VIDEO
Definition: avutil.h:201
AV_PIX_FMT_YUV422P
@ AV_PIX_FMT_YUV422P
planar YUV 4:2:2, 16bpp, (1 Cr & Cb sample per 2x1 Y samples)
Definition: pixfmt.h:77
mem.h
get_ue_golomb_long
static unsigned get_ue_golomb_long(GetBitContext *gb)
Read an unsigned Exp-Golomb code in the range 0 to UINT32_MAX-1.
Definition: golomb.h:104
FFALIGN
#define FFALIGN(x, a)
Definition: macros.h:78
AVPacket
This structure stores compressed data.
Definition: packet.h:501
AVCodecContext::priv_data
void * priv_data
Definition: avcodec.h:472
VMIXContext::scan
uint8_t scan[64]
Definition: vmixdec.c:50
av_freep
#define av_freep(p)
Definition: tableprint_vlc.h:34
AVCodecContext::width
int width
picture width / height.
Definition: avcodec.h:618
ff_vmix_decoder
const FFCodec ff_vmix_decoder
Definition: vmixdec.c:304
block
The exact code depends on how similar the blocks are and how related they are to the block
Definition: filter_design.txt:207
AVERROR_INVALIDDATA
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition: error.h:61
decode_slices
static int decode_slices(AVCodecContext *avctx, void *arg, int n, int thread_nb)
Definition: vmixdec.c:206
AVCodecContext::execute2
int(* execute2)(struct AVCodecContext *c, int(*func)(struct AVCodecContext *c2, void *arg, int jobnr, int threadnr), void *arg2, int *ret, int count)
The codec may call this to execute several independent things.
Definition: avcodec.h:1632
SliceContext::dc_ptr
const uint8_t * dc_ptr
Definition: vmixdec.c:39