path: root/libavcodec/psymodel.c (plain)
blob: 2b5f111fbe636ce6e7eba0efef0e99c72ee588d4

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	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
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
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
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_mallocz_array(sizeof(ctx->fstate[0]), avctx->channels);
124	if (!ctx->fstate) {
125	av_free(ctx->fcoeffs);
126	av_free(ctx);
127	return NULL;
128	}
129	for (i = 0; i < avctx->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
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
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->channels; i++)
158	ff_iir_filter_free_statep(&ctx->fstate[i]);
159	av_freep(&ctx->fstate);
160	av_free(ctx);
161	}
162