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_calloc(avctx->ch_layout.nb_channels, 2 * sizeof(ctx->ch[0]));
39 ctx->group = av_calloc(num_groups, sizeof(ctx->group[0]));
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 ctx->cutoff = avctx->cutoff;
43
44 if (!ctx->ch || !ctx->group || !ctx->bands || !ctx->num_bands) {
45 ff_psy_end(ctx);
46 return AVERROR(ENOMEM);
47 }
48
49 memcpy(ctx->bands, bands, sizeof(ctx->bands[0]) * num_lens);
50 memcpy(ctx->num_bands, num_bands, sizeof(ctx->num_bands[0]) * num_lens);
51
52 /* assign channels to groups (with virtual channels for coupling) */
53 for (i = 0; i < num_groups; i++) {
54 /* NOTE: Add 1 to handle the AAC chan_config without modification.
55 * This has the side effect of allowing an array of 0s to map
56 * to one channel per group.
57 */
58 ctx->group[i].num_ch = group_map[i] + 1;
59 for (j = 0; j < ctx->group[i].num_ch * 2; j++)
60 ctx->group[i].ch[j] = &ctx->ch[k++];
61 }
62
63 switch (ctx->avctx->codec_id) {
64 case AV_CODEC_ID_AAC:
65 ctx->model = &ff_aac_psy_model;
66 break;
67 }
68 if (ctx->model->init)
69 return ctx->model->init(ctx);
70 return 0;
71 }
72
ff_psy_find_group(FFPsyContext * ctx,int channel)73 FFPsyChannelGroup *ff_psy_find_group(FFPsyContext *ctx, int channel)
74 {
75 int i = 0, ch = 0;
76
77 while (ch <= channel)
78 ch += ctx->group[i++].num_ch;
79
80 return &ctx->group[i-1];
81 }
82
ff_psy_end(FFPsyContext * ctx)83 av_cold void ff_psy_end(FFPsyContext *ctx)
84 {
85 if (ctx->model && ctx->model->end)
86 ctx->model->end(ctx);
87 av_freep(&ctx->bands);
88 av_freep(&ctx->num_bands);
89 av_freep(&ctx->group);
90 av_freep(&ctx->ch);
91 }
92
93 typedef struct FFPsyPreprocessContext{
94 AVCodecContext *avctx;
95 float stereo_att;
96 struct FFIIRFilterCoeffs *fcoeffs;
97 struct FFIIRFilterState **fstate;
98 struct FFIIRFilterContext fiir;
99 }FFPsyPreprocessContext;
100
101 #define FILT_ORDER 4
102
ff_psy_preprocess_init(AVCodecContext * avctx)103 av_cold struct FFPsyPreprocessContext* ff_psy_preprocess_init(AVCodecContext *avctx)
104 {
105 FFPsyPreprocessContext *ctx;
106 int i;
107 float cutoff_coeff = 0;
108 ctx = av_mallocz(sizeof(FFPsyPreprocessContext));
109 if (!ctx)
110 return NULL;
111 ctx->avctx = avctx;
112
113 /* AAC has its own LP method */
114 if (avctx->codec_id != AV_CODEC_ID_AAC) {
115 if (avctx->cutoff > 0)
116 cutoff_coeff = 2.0 * avctx->cutoff / avctx->sample_rate;
117
118 if (cutoff_coeff && cutoff_coeff < 0.98)
119 ctx->fcoeffs = ff_iir_filter_init_coeffs(avctx, FF_FILTER_TYPE_BUTTERWORTH,
120 FF_FILTER_MODE_LOWPASS, FILT_ORDER,
121 cutoff_coeff, 0.0, 0.0);
122 if (ctx->fcoeffs) {
123 ctx->fstate = av_calloc(avctx->ch_layout.nb_channels, sizeof(ctx->fstate[0]));
124 if (!ctx->fstate) {
125 av_free(ctx->fcoeffs);
126 av_free(ctx);
127 return NULL;
128 }
129 for (i = 0; i < avctx->ch_layout.nb_channels; i++)
130 ctx->fstate[i] = ff_iir_filter_init_state(FILT_ORDER);
131 }
132 }
133
134 ff_iir_filter_init(&ctx->fiir);
135
136 return ctx;
137 }
138
ff_psy_preprocess(struct FFPsyPreprocessContext * ctx,float ** audio,int channels)139 void ff_psy_preprocess(struct FFPsyPreprocessContext *ctx, float **audio, int channels)
140 {
141 int ch;
142 int frame_size = ctx->avctx->frame_size;
143 FFIIRFilterContext *iir = &ctx->fiir;
144
145 if (ctx->fstate) {
146 for (ch = 0; ch < channels; ch++)
147 iir->filter_flt(ctx->fcoeffs, ctx->fstate[ch], frame_size,
148 &audio[ch][frame_size], 1, &audio[ch][frame_size], 1);
149 }
150 }
151
ff_psy_preprocess_end(struct FFPsyPreprocessContext * ctx)152 av_cold void ff_psy_preprocess_end(struct FFPsyPreprocessContext *ctx)
153 {
154 int i;
155 ff_iir_filter_free_coeffsp(&ctx->fcoeffs);
156 if (ctx->fstate)
157 for (i = 0; i < ctx->avctx->ch_layout.nb_channels; i++)
158 ff_iir_filter_free_statep(&ctx->fstate[i]);
159 av_freep(&ctx->fstate);
160 av_free(ctx);
161 }
162