FFmpeg coverage


Directory: ../../../ffmpeg/
File: src/libavcodec/cngdec.c
Date: 2021-09-26 18:22:30
Exec Total Coverage
Lines: 0 78 0.0%
Branches: 0 34 0.0%

Line Branch Exec Source
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 "libavutil/ffmath.h"
26 #include "libavutil/intreadwrite.h"
27 #include "avcodec.h"
28 #include "celp_filters.h"
29 #include "internal.h"
30 #include "libavutil/lfg.h"
31
32 typedef struct CNGContext {
33 float *refl_coef, *target_refl_coef;
34 float *lpc_coef;
35 int order;
36 int energy, target_energy;
37 int inited;
38 float *filter_out;
39 float *excitation;
40 AVLFG lfg;
41 } CNGContext;
42
43 static av_cold int cng_decode_close(AVCodecContext *avctx)
44 {
45 CNGContext *p = avctx->priv_data;
46 av_freep(&p->refl_coef);
47 av_freep(&p->target_refl_coef);
48 av_freep(&p->lpc_coef);
49 av_freep(&p->filter_out);
50 av_freep(&p->excitation);
51 return 0;
52 }
53
54 static av_cold int cng_decode_init(AVCodecContext *avctx)
55 {
56 CNGContext *p = avctx->priv_data;
57
58 avctx->sample_fmt = AV_SAMPLE_FMT_S16;
59 avctx->channels = 1;
60 avctx->sample_rate = 8000;
61
62 p->order = 12;
63 avctx->frame_size = 640;
64 p->refl_coef = av_calloc(p->order, sizeof(*p->refl_coef));
65 p->target_refl_coef = av_calloc(p->order, sizeof(*p->target_refl_coef));
66 p->lpc_coef = av_calloc(p->order, sizeof(*p->lpc_coef));
67 p->filter_out = av_calloc(avctx->frame_size + p->order,
68 sizeof(*p->filter_out));
69 p->excitation = av_calloc(avctx->frame_size, sizeof(*p->excitation));
70 if (!p->refl_coef || !p->target_refl_coef || !p->lpc_coef ||
71 !p->filter_out || !p->excitation) {
72 return AVERROR(ENOMEM);
73 }
74
75 av_lfg_init(&p->lfg, 0);
76
77 return 0;
78 }
79
80 static void make_lpc_coefs(float *lpc, const float *refl, int order)
81 {
82 float buf[100];
83 float *next, *cur;
84 int m, i;
85 next = buf;
86 cur = lpc;
87 for (m = 0; m < order; m++) {
88 next[m] = refl[m];
89 for (i = 0; i < m; i++)
90 next[i] = cur[i] + refl[m] * cur[m - i - 1];
91 FFSWAP(float*, next, cur);
92 }
93 if (cur != lpc)
94 memcpy(lpc, cur, sizeof(*lpc) * order);
95 }
96
97 static void cng_decode_flush(AVCodecContext *avctx)
98 {
99 CNGContext *p = avctx->priv_data;
100 p->inited = 0;
101 }
102
103 static int cng_decode_frame(AVCodecContext *avctx, void *data,
104 int *got_frame_ptr, AVPacket *avpkt)
105 {
106 AVFrame *frame = data;
107 CNGContext *p = avctx->priv_data;
108 int buf_size = avpkt->size;
109 int ret, i;
110 int16_t *buf_out;
111 float e = 1.0;
112 float scaling;
113
114 if (avpkt->size) {
115 int dbov = -avpkt->data[0];
116 p->target_energy = 1081109975 * ff_exp10(dbov / 10.0) * 0.75;
117 memset(p->target_refl_coef, 0, p->order * sizeof(*p->target_refl_coef));
118 for (i = 0; i < FFMIN(avpkt->size - 1, p->order); i++) {
119 p->target_refl_coef[i] = (avpkt->data[1 + i] - 127) / 128.0;
120 }
121 }
122
123 if (avctx->internal->skip_samples > 10 * avctx->frame_size) {
124 avctx->internal->skip_samples = 0;
125 return AVERROR_INVALIDDATA;
126 }
127
128 if (p->inited) {
129 p->energy = p->energy / 2 + p->target_energy / 2;
130 for (i = 0; i < p->order; i++)
131 p->refl_coef[i] = 0.6 *p->refl_coef[i] + 0.4 * p->target_refl_coef[i];
132 } else {
133 p->energy = p->target_energy;
134 memcpy(p->refl_coef, p->target_refl_coef, p->order * sizeof(*p->refl_coef));
135 p->inited = 1;
136 }
137 make_lpc_coefs(p->lpc_coef, p->refl_coef, p->order);
138
139 for (i = 0; i < p->order; i++)
140 e *= 1.0 - p->refl_coef[i]*p->refl_coef[i];
141
142 scaling = sqrt(e * p->energy / 1081109975);
143 for (i = 0; i < avctx->frame_size; i++) {
144 int r = (av_lfg_get(&p->lfg) & 0xffff) - 0x8000;
145 p->excitation[i] = scaling * r;
146 }
147 ff_celp_lp_synthesis_filterf(p->filter_out + p->order, p->lpc_coef,
148 p->excitation, avctx->frame_size, p->order);
149
150 frame->nb_samples = avctx->frame_size;
151 if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
152 return ret;
153 buf_out = (int16_t *)frame->data[0];
154 for (i = 0; i < avctx->frame_size; i++)
155 buf_out[i] = av_clip_int16(p->filter_out[i + p->order]);
156 memcpy(p->filter_out, p->filter_out + avctx->frame_size,
157 p->order * sizeof(*p->filter_out));
158
159 *got_frame_ptr = 1;
160
161 return buf_size;
162 }
163
164 const AVCodec ff_comfortnoise_decoder = {
165 .name = "comfortnoise",
166 .long_name = NULL_IF_CONFIG_SMALL("RFC 3389 comfort noise generator"),
167 .type = AVMEDIA_TYPE_AUDIO,
168 .id = AV_CODEC_ID_COMFORT_NOISE,
169 .priv_data_size = sizeof(CNGContext),
170 .init = cng_decode_init,
171 .decode = cng_decode_frame,
172 .flush = cng_decode_flush,
173 .close = cng_decode_close,
174 .sample_fmts = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S16,
175 AV_SAMPLE_FMT_NONE },
176 .capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_CHANNEL_CONF,
177 .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE |
178 FF_CODEC_CAP_INIT_CLEANUP,
179 };
180