FFmpeg coverage

Directory: ../../../ffmpeg/
File: src/libavcodec/cngdec.c
Date: 2026-09-26 20:14:34
Exec Total Coverage
Lines: 72 81 88.9%
Functions: 4 5 80.0%
Branches: 27 36 75.0%
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/mem.h"
27 #include "avcodec.h"
28 #include "celp_filters.h"
29 #include "codec_internal.h"
30 #include "decode.h"
31 #include "internal.h"
32 #include "libavutil/lfg.h"
33
34 typedef struct CNGContext {
35 float *refl_coef, *target_refl_coef;
36 float *lpc_coef;
37 int order;
38 int energy, target_energy;
39 int inited;
40 float *filter_out;
41 float *excitation;
42 AVLFG lfg;
43 } CNGContext;
44
45 4 static av_cold int cng_decode_close(AVCodecContext *avctx)
46 {
47 4 CNGContext *p = avctx->priv_data;
48 4 av_freep(&p->refl_coef);
49 4 av_freep(&p->target_refl_coef);
50 4 av_freep(&p->lpc_coef);
51 4 av_freep(&p->filter_out);
52 4 av_freep(&p->excitation);
53 4 return 0;
54 }
55
56 4 static av_cold int cng_decode_init(AVCodecContext *avctx)
57 {
58 4 CNGContext *p = avctx->priv_data;
59
60 4 avctx->sample_fmt = AV_SAMPLE_FMT_S16;
61 4 av_channel_layout_uninit(&avctx->ch_layout);
62 4 avctx->ch_layout = (AVChannelLayout)AV_CHANNEL_LAYOUT_MONO;
63 4 avctx->sample_rate = 8000;
64
65 4 p->order = 12;
66 4 avctx->frame_size = 640;
67 4 p->refl_coef = av_calloc(p->order, sizeof(*p->refl_coef));
68 4 p->target_refl_coef = av_calloc(p->order, sizeof(*p->target_refl_coef));
69 4 p->lpc_coef = av_calloc(p->order, sizeof(*p->lpc_coef));
70 4 p->filter_out = av_calloc(avctx->frame_size + p->order,
71 sizeof(*p->filter_out));
72 4 p->excitation = av_calloc(avctx->frame_size, sizeof(*p->excitation));
73
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 4 if (!p->refl_coef || !p->target_refl_coef || !p->lpc_coef ||
74
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 4 !p->filter_out || !p->excitation) {
75 ✗ return AVERROR(ENOMEM);
76 }
77
78 4 av_lfg_init(&p->lfg, 0);
79
80 4 return 0;
81 }
82
83 78 static void make_lpc_coefs(float *lpc, const float *refl, int order)
84 {
85 float buf[100];
86 float *next, *cur;
87 int m, i;
88 78 next = buf;
89 78 cur = lpc;
90
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 1014 for (m = 0; m < order; m++) {
91 936 next[m] = refl[m];
92
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 6084 for (i = 0; i < m; i++)
93 5148 next[i] = cur[i] + refl[m] * cur[m - i - 1];
94 936 FFSWAP(float*, next, cur);
95 }
96
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 78 if (cur != lpc)
97 ✗ memcpy(lpc, cur, sizeof(*lpc) * order);
98 78 }
99
100 ✗ static av_cold void cng_decode_flush(AVCodecContext *avctx)
101 {
102 ✗ CNGContext *p = avctx->priv_data;
103 ✗ p->inited = 0;
104 ✗ }
105
106 78 static int cng_decode_frame(AVCodecContext *avctx, AVFrame *frame,
107 int *got_frame_ptr, AVPacket *avpkt)
108 {
109 78 CNGContext *p = avctx->priv_data;
110 78 int buf_size = avpkt->size;
111 int ret, i;
112 int16_t *buf_out;
113 78 float e = 1.0;
114 float scaling;
115
116
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 78 if (avpkt->size) {
117 78 int dbov = -avpkt->data[0];
118 78 p->target_energy = 1081109975 * ff_exp10(dbov / 10.0) * 0.75;
119 78 memset(p->target_refl_coef, 0, p->order * sizeof(*p->target_refl_coef));
120
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 862 for (i = 0; i < FFMIN(avpkt->size - 1, p->order); i++) {
121 784 p->target_refl_coef[i] = (avpkt->data[1 + i] - 127) / 128.0;
122 }
123 }
124
125
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 78 if (avctx->internal->skip_samples > 10 * avctx->frame_size) {
126 ✗ avctx->internal->skip_samples = 0;
127 ✗ return AVERROR_INVALIDDATA;
128 }
129
130
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 78 if (p->inited) {
131 74 p->energy = p->energy / 2 + p->target_energy / 2;
132
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 962 for (i = 0; i < p->order; i++)
133 888 p->refl_coef[i] = 0.6 *p->refl_coef[i] + 0.4 * p->target_refl_coef[i];
134 } else {
135 4 p->energy = p->target_energy;
136 4 memcpy(p->refl_coef, p->target_refl_coef, p->order * sizeof(*p->refl_coef));
137 4 p->inited = 1;
138 }
139 78 make_lpc_coefs(p->lpc_coef, p->refl_coef, p->order);
140
141
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 1014 for (i = 0; i < p->order; i++)
142 936 e *= 1.0 - p->refl_coef[i]*p->refl_coef[i];
143
144 78 scaling = sqrt(e * p->energy / 1081109975);
145
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 49998 for (i = 0; i < avctx->frame_size; i++) {
146 49920 int r = (av_lfg_get(&p->lfg) & 0xffff) - 0x8000;
147 49920 p->excitation[i] = scaling * r;
148 }
149 78 ff_celp_lp_synthesis_filterf(p->filter_out + p->order, p->lpc_coef,
150 78 p->excitation, avctx->frame_size, p->order);
151
152 78 frame->nb_samples = avctx->frame_size;
153
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 78 if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
154 ✗ return ret;
155 78 buf_out = (int16_t *)frame->data[0];
156
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 49998 for (i = 0; i < avctx->frame_size; i++) {
157 49920 const float f = p->filter_out[i + p->order];
158
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 49920 buf_out[i] = !isfinite(f) ? 0 : av_clipf(f, INT16_MIN, INT16_MAX);
159 }
160 78 memcpy(p->filter_out, p->filter_out + avctx->frame_size,
161 78 p->order * sizeof(*p->filter_out));
162
163 78 *got_frame_ptr = 1;
164
165 78 return buf_size;
166 }
167
168 const FFCodec ff_comfortnoise_decoder = {
169 .p.name = "comfortnoise",
170 CODEC_LONG_NAME("RFC 3389 comfort noise generator"),
171 .p.type = AVMEDIA_TYPE_AUDIO,
172 .p.id = AV_CODEC_ID_COMFORT_NOISE,
173 .priv_data_size = sizeof(CNGContext),
174 .init = cng_decode_init,
175 FF_CODEC_DECODE_CB(cng_decode_frame),
176 .flush = cng_decode_flush,
177 .close = cng_decode_close,
178 .p.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_CHANNEL_CONF,
179 .caps_internal = FF_CODEC_CAP_INIT_CLEANUP,
180 };
181