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
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)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 memcpy(ctx->bands, bands, sizeof(ctx->bands[0]) * num_lens);
43 memcpy(ctx->num_bands, num_bands, sizeof(ctx->num_bands[0]) * num_lens);
44
45 /* assign channels to groups (with virtual channels for coupling) */
46 for (i = 0; i < num_groups; i++) {
47 /* NOTE: Add 1 to handle the AAC chan_config without modification.
48 * This has the side effect of allowing an array of 0s to map
49 * to one channel per group.
50 */
51 ctx->group[i].num_ch = group_map[i] + 1;
52 for (j = 0; j < ctx->group[i].num_ch * 2; j++)
53 ctx->group[i].ch[j] = &ctx->ch[k++];
54 }
55
56 switch (ctx->avctx->codec_id) {
57 case AV_CODEC_ID_AAC:
58 ctx->model = &ff_aac_psy_model;
59 break;
60 }
61 if (ctx->model->init)
62 return ctx->model->init(ctx);
63 return 0;
64 }
65
ff_psy_find_group(FFPsyContext * ctx,int channel)66 FFPsyChannelGroup *ff_psy_find_group(FFPsyContext *ctx, int channel)
67 {
68 int i = 0, ch = 0;
69
70 while (ch <= channel)
71 ch += ctx->group[i++].num_ch;
72
73 return &ctx->group[i-1];
74 }
75
ff_psy_end(FFPsyContext * ctx)76 av_cold void ff_psy_end(FFPsyContext *ctx)
77 {
78 if (ctx->model && ctx->model->end)
79 ctx->model->end(ctx);
80 av_freep(&ctx->bands);
81 av_freep(&ctx->num_bands);
82 av_freep(&ctx->group);
83 av_freep(&ctx->ch);
84 }
85
86 typedef struct FFPsyPreprocessContext{
87 AVCodecContext *avctx;
88 float stereo_att;
89 struct FFIIRFilterCoeffs *fcoeffs;
90 struct FFIIRFilterState **fstate;
91 struct FFIIRFilterContext fiir;
92 }FFPsyPreprocessContext;
93
94 #define FILT_ORDER 4
95
ff_psy_preprocess_init(AVCodecContext * avctx)96 av_cold struct FFPsyPreprocessContext* ff_psy_preprocess_init(AVCodecContext *avctx)
97 {
98 FFPsyPreprocessContext *ctx;
99 int i;
100 float cutoff_coeff = 0;
101 ctx = av_mallocz(sizeof(FFPsyPreprocessContext));
102 ctx->avctx = avctx;
103
104 if (avctx->cutoff > 0)
105 cutoff_coeff = 2.0 * avctx->cutoff / avctx->sample_rate;
106
107 if (!cutoff_coeff && avctx->codec_id == AV_CODEC_ID_AAC)
108 cutoff_coeff = 2.0 * AAC_CUTOFF(avctx) / avctx->sample_rate;
109
110 if (cutoff_coeff && cutoff_coeff < 0.98)
111 ctx->fcoeffs = ff_iir_filter_init_coeffs(avctx, FF_FILTER_TYPE_BUTTERWORTH,
112 FF_FILTER_MODE_LOWPASS, FILT_ORDER,
113 cutoff_coeff, 0.0, 0.0);
114 if (ctx->fcoeffs) {
115 ctx->fstate = av_mallocz_array(sizeof(ctx->fstate[0]), avctx->channels);
116 for (i = 0; i < avctx->channels; i++)
117 ctx->fstate[i] = ff_iir_filter_init_state(FILT_ORDER);
118 }
119
120 ff_iir_filter_init(&ctx->fiir);
121
122 return ctx;
123 }
124
ff_psy_preprocess(struct FFPsyPreprocessContext * ctx,float ** audio,int channels)125 void ff_psy_preprocess(struct FFPsyPreprocessContext *ctx, float **audio, int channels)
126 {
127 int ch;
128 int frame_size = ctx->avctx->frame_size;
129 FFIIRFilterContext *iir = &ctx->fiir;
130
131 if (ctx->fstate) {
132 for (ch = 0; ch < channels; ch++)
133 iir->filter_flt(ctx->fcoeffs, ctx->fstate[ch], frame_size,
134 &audio[ch][frame_size], 1, &audio[ch][frame_size], 1);
135 }
136 }
137
ff_psy_preprocess_end(struct FFPsyPreprocessContext * ctx)138 av_cold void ff_psy_preprocess_end(struct FFPsyPreprocessContext *ctx)
139 {
140 int i;
141 ff_iir_filter_free_coeffs(ctx->fcoeffs);
142 if (ctx->fstate)
143 for (i = 0; i < ctx->avctx->channels; i++)
144 ff_iir_filter_free_state(ctx->fstate[i]);
145 av_freep(&ctx->fstate);
146 av_free(ctx);
147 }
148