Libav
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 Libav.
6  *
7  * Libav 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  * Libav 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 Libav; 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(sizeof(ctx->ch[0]) * avctx->channels * 2);
39  ctx->group = av_mallocz(sizeof(ctx->group[0]) * num_groups);
40  ctx->bands = av_malloc (sizeof(ctx->bands[0]) * num_lens);
41  ctx->num_bands = av_malloc (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->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;
98 
99 #define FILT_ORDER 4
100 
102 {
104  int i;
105  float cutoff_coeff = 0;
106  ctx = av_mallocz(sizeof(FFPsyPreprocessContext));
107  if (!ctx)
108  return NULL;
109  ctx->avctx = avctx;
110 
111  if (avctx->cutoff > 0)
112  cutoff_coeff = 2.0 * avctx->cutoff / avctx->sample_rate;
113 
114  if (cutoff_coeff)
117  cutoff_coeff, 0.0, 0.0);
118  if (ctx->fcoeffs) {
119  ctx->fstate = av_mallocz(sizeof(ctx->fstate[0]) * avctx->channels);
120  if (!ctx->fstate) {
121  av_free(ctx);
122  return NULL;
123  }
124  for (i = 0; i < avctx->channels; i++)
126  }
127  return ctx;
128 }
129 
130 void ff_psy_preprocess(struct FFPsyPreprocessContext *ctx, float **audio, int channels)
131 {
132  int ch;
133  int frame_size = ctx->avctx->frame_size;
134 
135  if (ctx->fstate) {
136  for (ch = 0; ch < channels; ch++)
137  ff_iir_filter_flt(ctx->fcoeffs, ctx->fstate[ch], frame_size,
138  &audio[ch][frame_size], 1, &audio[ch][frame_size], 1);
139  }
140 }
141 
143 {
144  int i;
146  if (ctx->fstate)
147  for (i = 0; i < ctx->avctx->channels; i++)
149  av_freep(&ctx->fstate);
150  av_free(ctx);
151 }
void * av_malloc(size_t size)
Allocate a block of size bytes with alignment suitable for all memory accesses (including vectors if ...
Definition: mem.c:62
void(* end)(FFPsyContext *apc)
Definition: psymodel.h:124
uint8_t ** bands
scalefactor band sizes for possible frame sizes
Definition: psymodel.h:82
FFPsyChannelGroup * group
channel group information
Definition: psymodel.h:79
memory handling functions
static const uint8_t frame_size[4]
Definition: g723_1.h:219
av_cold void ff_psy_preprocess_end(struct FFPsyPreprocessContext *ctx)
Cleanup audio preprocessing module.
Definition: psymodel.c:142
psychoacoustic information for an arbitrary group of channels
Definition: psymodel.h:54
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:83
av_cold struct FFIIRFilterState * ff_iir_filter_init_state(int order)
Create new filter state.
Definition: iirfilter.c:204
void av_freep(void *arg)
Free a memory block which has been allocated with av_malloc(z)() or av_realloc() and set the pointer ...
Definition: mem.c:202
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:162
uint8_t
#define av_cold
Definition: attributes.h:66
struct FFIIRFilterCoeffs * fcoeffs
Definition: psymodel.c:95
context used by psychoacoustic model
Definition: psymodel.h:74
const FFPsyModel ff_aac_psy_model
Definition: aacpsy.c:933
AVCodecContext * avctx
Definition: psymodel.c:93
void av_free(void *ptr)
Free a memory block which has been allocated with av_malloc(z)() or av_realloc(). ...
Definition: mem.c:190
FFPsyChannel * ch[PSY_MAX_CHANS]
pointers to the individual channels in the group
Definition: psymodel.h:55
#define AVERROR(e)
Definition: error.h:43
codec-specific psychoacoustic model implementation
Definition: psymodel.h:97
IIR filter state.
Definition: iirfilter.c:47
void ff_iir_filter_flt(const struct FFIIRFilterCoeffs *c, struct FFIIRFilterState *s, int size, const float *src, int sstep, float *dst, int dstep)
Perform IIR filtering on floating-point input samples.
Definition: iirfilter.c:292
int(* init)(FFPsyContext *apc)
Definition: psymodel.h:99
uint8_t num_ch
number of channels in this group
Definition: psymodel.h:56
AVFormatContext * ctx
Definition: movenc.c:48
av_cold void ff_iir_filter_free_coeffs(struct FFIIRFilterCoeffs *coeffs)
Free filter coefficients.
Definition: iirfilter.c:310
int frame_size
Number of samples per channel in an audio frame.
Definition: avcodec.h:2172
NULL
Definition: eval.c:55
Libavcodec external API header.
enum AVCodecID codec_id
Definition: avcodec.h:1426
int sample_rate
samples per second
Definition: avcodec.h:2152
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:1409
const struct FFPsyModel * model
encoder-specific model functions
Definition: psymodel.h:76
IIR filter global parameters.
Definition: iirfilter.c:37
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:101
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:130
#define FILT_ORDER
Definition: psymodel.c:99
int cutoff
Audio cutoff bandwidth (0 means "automatic")
Definition: avcodec.h:2196
IIR filter interface.
int channels
number of audio channels
Definition: avcodec.h:2153
FFPsyChannel * ch
single channel information
Definition: psymodel.h:78
AVCodecContext * avctx
encoder context
Definition: psymodel.h:75
av_cold void ff_psy_end(FFPsyContext *ctx)
Cleanup model context at the end.
Definition: psymodel.c:82
av_cold void ff_iir_filter_free_state(struct FFIIRFilterState *state)
Free filter state.
Definition: iirfilter.c:305
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:211