FFmpeg
Data Structures | Macros | Functions | Variables
af_acrusher.c File Reference
#include "libavutil/opt.h"
#include "avfilter.h"
#include "internal.h"
#include "audio.h"

Go to the source code of this file.

Data Structures

struct  LFOContext
 
struct  SRContext
 
struct  ACrusherContext
 

Macros

#define OFFSET(x)   offsetof(ACrusherContext, x)
 
#define A   AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
 

Functions

 AVFILTER_DEFINE_CLASS (acrusher)
 
static double samplereduction (ACrusherContext *s, SRContext *sr, double in)
 
static double add_dc (double s, double dc, double idc)
 
static double remove_dc (double s, double dc, double idc)
 
static double factor (double y, double k, double aa1, double aa)
 
static double bitreduction (ACrusherContext *s, double in)
 
static double lfo_get (LFOContext *lfo)
 
static void lfo_advance (LFOContext *lfo, unsigned count)
 
static int filter_frame (AVFilterLink *inlink, AVFrame *in)
 
static int query_formats (AVFilterContext *ctx)
 
static av_cold void uninit (AVFilterContext *ctx)
 
static int config_input (AVFilterLink *inlink)
 

Variables

static const AVOption acrusher_options []
 
static const AVFilterPad avfilter_af_acrusher_inputs []
 
static const AVFilterPad avfilter_af_acrusher_outputs []
 
AVFilter ff_af_acrusher
 

Macro Definition Documentation

#define OFFSET (   x)    offsetof(ACrusherContext, x)

Definition at line 70 of file af_acrusher.c.

Definition at line 71 of file af_acrusher.c.

Function Documentation

AVFILTER_DEFINE_CLASS ( acrusher  )
static double samplereduction ( ACrusherContext s,
SRContext sr,
double  in 
)
static

Definition at line 92 of file af_acrusher.c.

Referenced by filter_frame().

static double add_dc ( double  s,
double  dc,
double  idc 
)
static

Definition at line 108 of file af_acrusher.c.

Referenced by bitreduction().

static double remove_dc ( double  s,
double  dc,
double  idc 
)
static

Definition at line 113 of file af_acrusher.c.

Referenced by bitreduction().

static double factor ( double  y,
double  k,
double  aa1,
double  aa 
)
inlinestatic

Definition at line 118 of file af_acrusher.c.

Referenced by bitreduction().

static double bitreduction ( ACrusherContext s,
double  in 
)
static

Definition at line 123 of file af_acrusher.c.

Referenced by filter_frame().

static double lfo_get ( LFOContext lfo)
static

Definition at line 196 of file af_acrusher.c.

Referenced by filter_frame().

static void lfo_advance ( LFOContext lfo,
unsigned  count 
)
static

Definition at line 209 of file af_acrusher.c.

Referenced by filter_frame().

static int filter_frame ( AVFilterLink inlink,
AVFrame in 
)
static

Definition at line 216 of file af_acrusher.c.

static int query_formats ( AVFilterContext ctx)
static

Definition at line 266 of file af_acrusher.c.

static av_cold void uninit ( AVFilterContext ctx)
static

Definition at line 296 of file af_acrusher.c.

static int config_input ( AVFilterLink inlink)
static

Definition at line 303 of file af_acrusher.c.

Variable Documentation

const AVOption acrusher_options[]
static
Initial value:
= {
{ "level_in", "set level in", OFFSET(level_in), AV_OPT_TYPE_DOUBLE, {.dbl=1}, 0.015625, 64, A },
{ "level_out","set level out", OFFSET(level_out), AV_OPT_TYPE_DOUBLE, {.dbl=1}, 0.015625, 64, A },
{ "bits", "set bit reduction", OFFSET(bits), AV_OPT_TYPE_DOUBLE, {.dbl=8}, 1, 64, A },
{ "mix", "set mix", OFFSET(mix), AV_OPT_TYPE_DOUBLE, {.dbl=.5}, 0, 1, A },
{ "mode", "set mode", OFFSET(mode), AV_OPT_TYPE_INT, {.i64=0}, 0, 1, A, "mode" },
{ "lin", "linear", 0, AV_OPT_TYPE_CONST, {.i64=0}, 0, 0, A, "mode" },
{ "log", "logarithmic", 0, AV_OPT_TYPE_CONST, {.i64=1}, 0, 0, A, "mode" },
{ "dc", "set DC", OFFSET(dc), AV_OPT_TYPE_DOUBLE, {.dbl=1}, .25, 4, A },
{ "aa", "set anti-aliasing", OFFSET(aa), AV_OPT_TYPE_DOUBLE, {.dbl=.5}, 0, 1, A },
{ "samples", "set sample reduction", OFFSET(samples), AV_OPT_TYPE_DOUBLE, {.dbl=1}, 1, 250, A },
{ "lfo", "enable LFO", OFFSET(is_lfo), AV_OPT_TYPE_BOOL, {.i64=0}, 0, 1, A },
{ "lforange", "set LFO depth", OFFSET(lforange), AV_OPT_TYPE_DOUBLE, {.dbl=20}, 1, 250, A },
{ "lforate", "set LFO rate", OFFSET(lforate), AV_OPT_TYPE_DOUBLE, {.dbl=.3}, .01, 200, A },
{ NULL }
}
#define NULL
Definition: coverity.c:32
uint8_t bits
Definition: vp3data.h:202
#define OFFSET(x)
Definition: af_acrusher.c:70
static int mix(int c0, int c1)
Definition: 4xm.c:714
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
#define A
Definition: af_acrusher.c:71
Filter the word “frame” indicates either a video frame or a group of audio samples
mode
Use these values in ebur128_init (or&#39;ed).
Definition: ebur128.h:83

Definition at line 73 of file af_acrusher.c.

const AVFilterPad avfilter_af_acrusher_inputs[]
static
Initial value:
= {
{
.name = "default",
.config_props = config_input,
.filter_frame = filter_frame,
},
{ NULL }
}
#define NULL
Definition: coverity.c:32
static int filter_frame(AVFilterLink *inlink, AVFrame *in)
Definition: af_acrusher.c:216
static int config_input(AVFilterLink *inlink)
Definition: af_acrusher.c:303

Definition at line 335 of file af_acrusher.c.

const AVFilterPad avfilter_af_acrusher_outputs[]
static
Initial value:
= {
{
.name = "default",
},
{ NULL }
}
#define NULL
Definition: coverity.c:32

Definition at line 345 of file af_acrusher.c.

AVFilter ff_af_acrusher
Initial value:
= {
.name = "acrusher",
.description = NULL_IF_CONFIG_SMALL("Reduce audio bit resolution."),
.priv_size = sizeof(ACrusherContext),
.priv_class = &acrusher_class,
}
static int query_formats(AVFilterContext *ctx)
Definition: af_acrusher.c:266
static const AVFilterPad avfilter_af_acrusher_inputs[]
Definition: af_acrusher.c:335
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
Definition: internal.h:186
static const AVFilterPad outputs[]
Definition: af_acontrast.c:203
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
static const AVFilterPad avfilter_af_acrusher_outputs[]
Definition: af_acrusher.c:345
static av_cold void uninit(AVFilterContext *ctx)
Definition: af_acrusher.c:296

Definition at line 353 of file af_acrusher.c.