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psymodel.c
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1 /*
2  * audio encoder psychoacoustic model
3  * Copyright (C) 2008 Konstantin Shishkov
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 <string.h>
23 
24 #include "avcodec.h"
25 #include "psymodel.h"
26 #include "iirfilter.h"
27 #include "libavutil/mem.h"
28 
29 extern const FFPsyModel ff_aac_psy_model;
30 
31 av_cold int ff_psy_init(FFPsyContext *ctx, AVCodecContext *avctx, int num_lens,
32  const uint8_t **bands, const int* num_bands,
33  int num_groups, const uint8_t *group_map)
34 {
35  int i, j, k = 0;
36 
37  ctx->avctx = avctx;
38  ctx->ch = av_mallocz_array(sizeof(ctx->ch[0]), avctx->channels * 2);
39  ctx->group = av_mallocz_array(sizeof(ctx->group[0]), num_groups);
40  ctx->bands = av_malloc_array (sizeof(ctx->bands[0]), num_lens);
41  ctx->num_bands = av_malloc_array (sizeof(ctx->num_bands[0]), num_lens);
42 
43  if (!ctx->ch || !ctx->group || !ctx->bands || !ctx->num_bands) {
44  ff_psy_end(ctx);
45  return AVERROR(ENOMEM);
46  }
47 
48  memcpy(ctx->bands, bands, sizeof(ctx->bands[0]) * num_lens);
49  memcpy(ctx->num_bands, num_bands, sizeof(ctx->num_bands[0]) * num_lens);
50 
51  /* assign channels to groups (with virtual channels for coupling) */
52  for (i = 0; i < num_groups; i++) {
53  /* NOTE: Add 1 to handle the AAC chan_config without modification.
54  * This has the side effect of allowing an array of 0s to map
55  * to one channel per group.
56  */
57  ctx->group[i].num_ch = group_map[i] + 1;
58  for (j = 0; j < ctx->group[i].num_ch * 2; j++)
59  ctx->group[i].ch[j] = &ctx->ch[k++];
60  }
61 
62  switch (ctx->avctx->codec_id) {
63  case AV_CODEC_ID_AAC:
64  ctx->model = &ff_aac_psy_model;
65  break;
66  }
67  if (ctx->model->init)
68  return ctx->model->init(ctx);
69  return 0;
70 }
71 
73 {
74  int i = 0, ch = 0;
75 
76  while (ch <= channel)
77  ch += ctx->group[i++].num_ch;
78 
79  return &ctx->group[i-1];
80 }
81 
83 {
84  if (ctx->model && ctx->model->end)
85  ctx->model->end(ctx);
86  av_freep(&ctx->bands);
87  av_freep(&ctx->num_bands);
88  av_freep(&ctx->group);
89  av_freep(&ctx->ch);
90 }
91 
92 typedef struct FFPsyPreprocessContext{
94  float stereo_att;
99 
100 #define FILT_ORDER 4
101 
103 {
105  int i;
106  float cutoff_coeff = 0;
107  ctx = av_mallocz(sizeof(FFPsyPreprocessContext));
108  if (!ctx)
109  return NULL;
110  ctx->avctx = avctx;
111 
112  if (avctx->cutoff > 0)
113  cutoff_coeff = 2.0 * avctx->cutoff / avctx->sample_rate;
114 
115  if (!cutoff_coeff && avctx->codec_id == AV_CODEC_ID_AAC)
116  cutoff_coeff = 2.0 * AAC_CUTOFF(avctx) / avctx->sample_rate;
117 
118  if (cutoff_coeff && cutoff_coeff < 0.98)
121  cutoff_coeff, 0.0, 0.0);
122  if (ctx->fcoeffs) {
123  ctx->fstate = av_mallocz_array(sizeof(ctx->fstate[0]), avctx->channels);
124  if (!ctx->fstate) {
125  av_free(ctx);
126  return NULL;
127  }
128  for (i = 0; i < avctx->channels; i++)
130  }
131 
132  ff_iir_filter_init(&ctx->fiir);
133 
134  return ctx;
135 }
136 
137 void ff_psy_preprocess(struct FFPsyPreprocessContext *ctx, float **audio, int channels)
138 {
139  int ch;
140  int frame_size = ctx->avctx->frame_size;
141  FFIIRFilterContext *iir = &ctx->fiir;
142 
143  if (ctx->fstate) {
144  for (ch = 0; ch < channels; ch++)
145  iir->filter_flt(ctx->fcoeffs, ctx->fstate[ch], frame_size,
146  &audio[ch][frame_size], 1, &audio[ch][frame_size], 1);
147  }
148 }
149 
151 {
152  int i;
154  if (ctx->fstate)
155  for (i = 0; i < ctx->avctx->channels; i++)
157  av_freep(&ctx->fstate);
158  av_free(ctx);
159 }
#define NULL
Definition: coverity.c:32
void(* filter_flt)(const struct FFIIRFilterCoeffs *coeffs, struct FFIIRFilterState *state, int size, const float *src, int sstep, float *dst, int dstep)
Perform IIR filtering on floating-point input samples.
Definition: iirfilter.h:62
uint8_t ** bands
scalefactor band sizes for possible frame sizes
Definition: psymodel.h:84
FFPsyChannelGroup * group
channel group information
Definition: psymodel.h:81
memory handling functions
av_cold void ff_psy_preprocess_end(struct FFPsyPreprocessContext *ctx)
Cleanup audio preprocessing module.
Definition: psymodel.c:150
psychoacoustic information for an arbitrary group of channels
Definition: psymodel.h:55
av_cold int ff_psy_init(FFPsyContext *ctx, AVCodecContext *avctx, int num_lens, const uint8_t **bands, const int *num_bands, int num_groups, const uint8_t *group_map)
Initialize psychoacoustic model.
Definition: psymodel.c:31
int * num_bands
number of scalefactor bands for possible frame sizes
Definition: psymodel.h:85
av_cold struct FFIIRFilterState * ff_iir_filter_init_state(int order)
Create new filter state.
Definition: iirfilter.c:203
av_cold struct FFIIRFilterCoeffs * ff_iir_filter_init_coeffs(void *avc, enum IIRFilterType filt_type, enum IIRFilterMode filt_mode, int order, float cutoff_ratio, float stopband, float ripple)
Initialize filter coefficients.
Definition: iirfilter.c:161
uint8_t
#define av_cold
Definition: attributes.h:74
struct FFIIRFilterCoeffs * fcoeffs
Definition: psymodel.c:95
context used by psychoacoustic model
Definition: psymodel.h:76
#define AAC_CUTOFF(s)
Definition: psymodel.h:32
const FFPsyModel ff_aac_psy_model
Definition: aacpsy.c:998
AVCodecContext * avctx
Definition: psymodel.c:93
FFPsyChannel * ch[PSY_MAX_CHANS]
pointers to the individual channels in the group
Definition: psymodel.h:56
#define AVERROR(e)
Definition: error.h:43
av_cold void ff_iir_filter_free_statep(struct FFIIRFilterState **state)
Free and zero filter state.
Definition: iirfilter.c:302
Libavcodec external API header.
codec-specific psychoacoustic model implementation
Definition: psymodel.h:99
IIR filter state.
Definition: iirfilter.c:45
uint8_t num_ch
number of channels in this group
Definition: psymodel.h:57
int frame_size
Number of samples per channel in an audio frame.
Definition: avcodec.h:2282
int frame_size
Definition: mxfenc.c:1803
enum AVCodecID codec_id
Definition: avcodec.h:1519
int sample_rate
samples per second
Definition: avcodec.h:2262
FFPsyChannelGroup * ff_psy_find_group(FFPsyContext *ctx, int channel)
Determine what group a channel belongs to.
Definition: psymodel.c:72
main external API structure.
Definition: avcodec.h:1502
void(* end)(FFPsyContext *apc)
Definition: psymodel.h:126
const struct FFPsyModel * model
encoder-specific model functions
Definition: psymodel.h:78
IIR filter global parameters.
Definition: iirfilter.c:35
void ff_iir_filter_init(FFIIRFilterContext *f)
Initialize FFIIRFilterContext.
Definition: iirfilter.c:317
struct FFIIRFilterState ** fstate
Definition: psymodel.c:96
av_cold struct FFPsyPreprocessContext * ff_psy_preprocess_init(AVCodecContext *avctx)
psychoacoustic model audio preprocessing initialization
Definition: psymodel.c:102
void ff_psy_preprocess(struct FFPsyPreprocessContext *ctx, float **audio, int channels)
Preprocess several channel in audio frame in order to compress it better.
Definition: psymodel.c:137
#define FILT_ORDER
Definition: psymodel.c:100
struct FFIIRFilterContext fiir
Definition: psymodel.c:97
int cutoff
Audio cutoff bandwidth (0 means "automatic")
Definition: avcodec.h:2306
#define av_free(p)
IIR filter interface.
int channels
number of audio channels
Definition: avcodec.h:2263
FFPsyChannel * ch
single channel information
Definition: psymodel.h:80
int(* init)(FFPsyContext *apc)
Definition: psymodel.h:101
static void * av_mallocz_array(size_t nmemb, size_t size)
Definition: mem.h:228
#define av_freep(p)
av_cold void ff_iir_filter_free_coeffsp(struct FFIIRFilterCoeffs **coeffsp)
Free filter coefficients.
Definition: iirfilter.c:307
#define av_malloc_array(a, b)
AVCodecContext * avctx
encoder context
Definition: psymodel.h:77
av_cold void ff_psy_end(FFPsyContext *ctx)
Cleanup model context at the end.
Definition: psymodel.c:82
void * av_mallocz(size_t size)
Allocate a block of size bytes with alignment suitable for all memory accesses (including vectors if ...
Definition: mem.c:252