Imported Debian version 2.5.3~trusty1
[deb_ffmpeg.git] / ffmpeg / libavcodec / cngdec.c
1 /*
2 * RFC 3389 comfort noise generator
3 * Copyright (c) 2012 Martin Storsjo
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 <math.h>
23
24 #include "libavutil/common.h"
25 #include "avcodec.h"
26 #include "celp_filters.h"
27 #include "internal.h"
28 #include "libavutil/lfg.h"
29
30 typedef struct CNGContext {
31 float *refl_coef, *target_refl_coef;
32 float *lpc_coef;
33 int order;
34 int energy, target_energy;
35 int inited;
36 float *filter_out;
37 float *excitation;
38 AVLFG lfg;
39 } CNGContext;
40
41 static av_cold int cng_decode_close(AVCodecContext *avctx)
42 {
43 CNGContext *p = avctx->priv_data;
44 av_freep(&p->refl_coef);
45 av_freep(&p->target_refl_coef);
46 av_freep(&p->lpc_coef);
47 av_freep(&p->filter_out);
48 av_freep(&p->excitation);
49 return 0;
50 }
51
52 static av_cold int cng_decode_init(AVCodecContext *avctx)
53 {
54 CNGContext *p = avctx->priv_data;
55
56 avctx->sample_fmt = AV_SAMPLE_FMT_S16;
57 avctx->channels = 1;
58 avctx->sample_rate = 8000;
59
60 p->order = 12;
61 avctx->frame_size = 640;
62 p->refl_coef = av_mallocz_array(p->order, sizeof(*p->refl_coef));
63 p->target_refl_coef = av_mallocz_array(p->order, sizeof(*p->target_refl_coef));
64 p->lpc_coef = av_mallocz_array(p->order, sizeof(*p->lpc_coef));
65 p->filter_out = av_mallocz_array(avctx->frame_size + p->order,
66 sizeof(*p->filter_out));
67 p->excitation = av_mallocz_array(avctx->frame_size, sizeof(*p->excitation));
68 if (!p->refl_coef || !p->target_refl_coef || !p->lpc_coef ||
69 !p->filter_out || !p->excitation) {
70 cng_decode_close(avctx);
71 return AVERROR(ENOMEM);
72 }
73
74 av_lfg_init(&p->lfg, 0);
75
76 return 0;
77 }
78
79 static void make_lpc_coefs(float *lpc, const float *refl, int order)
80 {
81 float buf[100];
82 float *next, *cur;
83 int m, i;
84 next = buf;
85 cur = lpc;
86 for (m = 0; m < order; m++) {
87 next[m] = refl[m];
88 for (i = 0; i < m; i++)
89 next[i] = cur[i] + refl[m] * cur[m - i - 1];
90 FFSWAP(float*, next, cur);
91 }
92 if (cur != lpc)
93 memcpy(lpc, cur, sizeof(*lpc) * order);
94 }
95
96 static void cng_decode_flush(AVCodecContext *avctx)
97 {
98 CNGContext *p = avctx->priv_data;
99 p->inited = 0;
100 }
101
102 static int cng_decode_frame(AVCodecContext *avctx, void *data,
103 int *got_frame_ptr, AVPacket *avpkt)
104 {
105 AVFrame *frame = data;
106 CNGContext *p = avctx->priv_data;
107 int buf_size = avpkt->size;
108 int ret, i;
109 int16_t *buf_out;
110 float e = 1.0;
111 float scaling;
112
113 if (avpkt->size) {
114 int dbov = -avpkt->data[0];
115 p->target_energy = 1081109975 * pow(10, dbov / 10.0) * 0.75;
116 memset(p->target_refl_coef, 0, p->order * sizeof(*p->target_refl_coef));
117 for (i = 0; i < FFMIN(avpkt->size - 1, p->order); i++) {
118 p->target_refl_coef[i] = (avpkt->data[1 + i] - 127) / 128.0;
119 }
120 }
121
122 if (p->inited) {
123 p->energy = p->energy / 2 + p->target_energy / 2;
124 for (i = 0; i < p->order; i++)
125 p->refl_coef[i] = 0.6 *p->refl_coef[i] + 0.4 * p->target_refl_coef[i];
126 } else {
127 p->energy = p->target_energy;
128 memcpy(p->refl_coef, p->target_refl_coef, p->order * sizeof(*p->refl_coef));
129 p->inited = 1;
130 }
131 make_lpc_coefs(p->lpc_coef, p->refl_coef, p->order);
132
133 for (i = 0; i < p->order; i++)
134 e *= 1.0 - p->refl_coef[i]*p->refl_coef[i];
135
136 scaling = sqrt(e * p->energy / 1081109975);
137 for (i = 0; i < avctx->frame_size; i++) {
138 int r = (av_lfg_get(&p->lfg) & 0xffff) - 0x8000;
139 p->excitation[i] = scaling * r;
140 }
141 ff_celp_lp_synthesis_filterf(p->filter_out + p->order, p->lpc_coef,
142 p->excitation, avctx->frame_size, p->order);
143
144 frame->nb_samples = avctx->frame_size;
145 if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
146 return ret;
147 buf_out = (int16_t *)frame->data[0];
148 for (i = 0; i < avctx->frame_size; i++)
149 buf_out[i] = p->filter_out[i + p->order];
150 memcpy(p->filter_out, p->filter_out + avctx->frame_size,
151 p->order * sizeof(*p->filter_out));
152
153 *got_frame_ptr = 1;
154
155 return buf_size;
156 }
157
158 AVCodec ff_comfortnoise_decoder = {
159 .name = "comfortnoise",
160 .long_name = NULL_IF_CONFIG_SMALL("RFC 3389 comfort noise generator"),
161 .type = AVMEDIA_TYPE_AUDIO,
162 .id = AV_CODEC_ID_COMFORT_NOISE,
163 .priv_data_size = sizeof(CNGContext),
164 .init = cng_decode_init,
165 .decode = cng_decode_frame,
166 .flush = cng_decode_flush,
167 .close = cng_decode_close,
168 .sample_fmts = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S16,
169 AV_SAMPLE_FMT_NONE },
170 .capabilities = CODEC_CAP_DELAY | CODEC_CAP_DR1,
171 };