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|AV_OPT_FLAG_RUNTIME_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)
 
static int process_command (AVFilterContext *ctx, const char *cmd, const char *args, char *res, int res_len, int flags)
 

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

◆ OFFSET

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

Definition at line 70 of file af_acrusher.c.

◆ A

Definition at line 71 of file af_acrusher.c.

Function Documentation

◆ AVFILTER_DEFINE_CLASS()

AVFILTER_DEFINE_CLASS ( acrusher  )

◆ samplereduction()

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

Definition at line 92 of file af_acrusher.c.

Referenced by filter_frame().

◆ add_dc()

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

Definition at line 108 of file af_acrusher.c.

Referenced by bitreduction().

◆ remove_dc()

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

Definition at line 113 of file af_acrusher.c.

Referenced by bitreduction().

◆ factor()

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

Definition at line 118 of file af_acrusher.c.

Referenced by bitreduction().

◆ bitreduction()

static double bitreduction ( ACrusherContext s,
double  in 
)
static

Definition at line 123 of file af_acrusher.c.

Referenced by filter_frame().

◆ lfo_get()

static double lfo_get ( LFOContext lfo)
static

Definition at line 196 of file af_acrusher.c.

Referenced by filter_frame().

◆ lfo_advance()

static void lfo_advance ( LFOContext lfo,
unsigned  count 
)
static

Definition at line 209 of file af_acrusher.c.

Referenced by filter_frame().

◆ filter_frame()

static int filter_frame ( AVFilterLink inlink,
AVFrame in 
)
static

Definition at line 216 of file af_acrusher.c.

◆ query_formats()

static int query_formats ( AVFilterContext ctx)
static

Definition at line 266 of file af_acrusher.c.

◆ uninit()

static av_cold void uninit ( AVFilterContext ctx)
static

Definition at line 296 of file af_acrusher.c.

◆ config_input()

static int config_input ( AVFilterLink inlink)
static

Definition at line 303 of file af_acrusher.c.

Referenced by process_command().

◆ process_command()

static int process_command ( AVFilterContext ctx,
const char *  cmd,
const char *  args,
char *  res,
int  res_len,
int  flags 
)
static

Definition at line 336 of file af_acrusher.c.

Variable Documentation

◆ acrusher_options

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 }
}

Definition at line 73 of file af_acrusher.c.

◆ avfilter_af_acrusher_inputs

const AVFilterPad avfilter_af_acrusher_inputs[]
static
Initial value:
= {
{
.name = "default",
.config_props = config_input,
.filter_frame = filter_frame,
},
{ NULL }
}

Definition at line 349 of file af_acrusher.c.

◆ avfilter_af_acrusher_outputs

const AVFilterPad avfilter_af_acrusher_outputs[]
static
Initial value:
= {
{
.name = "default",
},
{ NULL }
}

Definition at line 359 of file af_acrusher.c.

◆ ff_af_acrusher

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,
}

Definition at line 367 of file af_acrusher.c.

mix
static int mix(int c0, int c1)
Definition: 4xm.c:715
query_formats
static int query_formats(AVFilterContext *ctx)
Definition: af_acrusher.c:266
filter_frame
static int filter_frame(AVFilterLink *inlink, AVFrame *in)
Definition: af_acrusher.c:216
OFFSET
#define OFFSET(x)
Definition: af_acrusher.c:70
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
ACrusherContext
Definition: af_acrusher.c:42
AV_OPT_TYPE_DOUBLE
@ AV_OPT_TYPE_DOUBLE
Definition: opt.h:227
AVMEDIA_TYPE_AUDIO
@ AVMEDIA_TYPE_AUDIO
Definition: avutil.h:202
bits
uint8_t bits
Definition: vp3data.h:141
outputs
static const AVFilterPad outputs[]
Definition: af_acontrast.c:203
NULL
#define NULL
Definition: coverity.c:32
uninit
static av_cold void uninit(AVFilterContext *ctx)
Definition: af_acrusher.c:296
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
NULL_IF_CONFIG_SMALL
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification.
Definition: internal.h:117
process_command
static int process_command(AVFilterContext *ctx, const char *cmd, const char *args, char *res, int res_len, int flags)
Definition: af_acrusher.c:336
avfilter_af_acrusher_inputs
static const AVFilterPad avfilter_af_acrusher_inputs[]
Definition: af_acrusher.c:349
avfilter_af_acrusher_outputs
static const AVFilterPad avfilter_af_acrusher_outputs[]
Definition: af_acrusher.c:359
config_input
static int config_input(AVFilterLink *inlink)
Definition: af_acrusher.c:303
A
#define A
Definition: af_acrusher.c:71
mode
mode
Definition: ebur128.h:83
AV_OPT_TYPE_INT
@ AV_OPT_TYPE_INT
Definition: opt.h:225
samples
Filter the word “frame” indicates either a video frame or a group of audio samples
Definition: filter_design.txt:8
AV_OPT_TYPE_BOOL
@ AV_OPT_TYPE_BOOL
Definition: opt.h:242
AV_OPT_TYPE_CONST
@ AV_OPT_TYPE_CONST
Definition: opt.h:234