FFmpeg coverage


Directory: ../../../ffmpeg/
File: src/libavformat/codec2.c
Date: 2026-08-15 14:54:27
Exec Total Coverage
Lines: 3 98 3.1%
Functions: 1 9 11.1%
Branches: 1 52 1.9%

Line Branch Exec Source
1 /*
2 * codec2 muxer and demuxers
3 * Copyright (c) 2017 Tomas Härdin
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 "config_components.h"
23
24 #include "libavcodec/codec2utils.h"
25 #include "libavutil/channel_layout.h"
26 #include "libavutil/intreadwrite.h"
27 #include "libavutil/opt.h"
28 #include "avio_internal.h"
29 #include "avformat.h"
30 #include "demux.h"
31 #include "internal.h"
32 #include "mux.h"
33 #include "rawenc.h"
34 #include "pcm.h"
35
36 #define CODEC2_HEADER_SIZE 7
37 #define CODEC2_MAGIC 0xC0DEC2
38
39 //the lowest version we should ever run across is 0.8
40 //we may run across later versions as the format evolves
41 #define EXPECTED_CODEC2_MAJOR_VERSION 0
42 #define EXPECTED_CODEC2_MINOR_VERSION 8
43
44 typedef struct {
45 const AVClass *class;
46 int mode;
47 int frames_per_packet;
48 } Codec2Context;
49
50 7800 static int codec2_probe(const AVProbeData *p)
51 {
52 //must start wih C0 DE C2
53
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7800 if (AV_RB24(p->buf) != CODEC2_MAGIC) {
54 7800 return 0;
55 }
56
57 //no .c2 files prior to 0.8
58 //be strict about major version while we're at it
59 if (p->buf[3] != EXPECTED_CODEC2_MAJOR_VERSION ||
60 p->buf[4] < EXPECTED_CODEC2_MINOR_VERSION) {
61 return 0;
62 }
63
64 //32 bits of identification -> low score
65 return AVPROBE_SCORE_EXTENSION + 1;
66 }
67
68 //Mimics codec2_samples_per_frame()
69 static int codec2_mode_frame_size(AVFormatContext *s, int mode)
70 {
71 int frame_size_table[CODEC2_MODE_MAX+1] = {
72 160, // 3200
73 160, // 2400
74 320, // 1600
75 320, // 1400
76 320, // 1300
77 320, // 1200
78 320, // 700
79 320, // 700B
80 320, // 700C
81 };
82
83 if (mode < 0 || mode > CODEC2_MODE_MAX) {
84 av_log(s, AV_LOG_ERROR, "unknown codec2 mode %i, can't find frame_size\n", mode);
85 return 0;
86 } else {
87 return frame_size_table[mode];
88 }
89 }
90
91 //Mimics (codec2_bits_per_frame()+7)/8
92 static int codec2_mode_block_align(AVFormatContext *s, int mode)
93 {
94 int block_align_table[CODEC2_MODE_MAX+1] = {
95 8, // 3200
96 6, // 2400
97 8, // 1600
98 7, // 1400
99 7, // 1300
100 6, // 1200
101 4, // 700
102 4, // 700B
103 4, // 700C
104 };
105
106 if (mode < 0 || mode > CODEC2_MODE_MAX) {
107 av_log(s, AV_LOG_ERROR, "unknown codec2 mode %i, can't find block_align\n", mode);
108 return 0;
109 } else {
110 return block_align_table[mode];
111 }
112 }
113
114 //Computes bitrate from mode, with frames rounded up to the nearest octet.
115 //So 700 bit/s (28 bits/frame) becomes 800 bits/s (32 bits/frame).
116 static int codec2_mode_bit_rate(AVFormatContext *s, int mode)
117 {
118 int frame_size = codec2_mode_frame_size(s, mode);
119 int block_align = codec2_mode_block_align(s, mode);
120
121 if (frame_size <= 0 || block_align <= 0) {
122 return 0;
123 }
124
125 return 8 * 8000 * block_align / frame_size;
126 }
127
128 static int codec2_read_header_common(AVFormatContext *s, AVStream *st)
129 {
130 int mode = codec2_mode_from_extradata(st->codecpar->extradata);
131
132 st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
133 st->codecpar->codec_id = AV_CODEC_ID_CODEC2;
134 st->codecpar->sample_rate = 8000;
135 st->codecpar->format = AV_SAMPLE_FMT_S16;
136 st->codecpar->ch_layout = (AVChannelLayout)AV_CHANNEL_LAYOUT_MONO;
137 st->codecpar->bit_rate = codec2_mode_bit_rate(s, mode);
138 st->codecpar->frame_size = codec2_mode_frame_size(s, mode);
139 st->codecpar->block_align = codec2_mode_block_align(s, mode);
140
141 if (st->codecpar->bit_rate <= 0 ||
142 st->codecpar->frame_size <= 0 ||
143 st->codecpar->block_align <= 0) {
144 return AVERROR_INVALIDDATA;
145 }
146
147 avpriv_set_pts_info(st, 64, 1, st->codecpar->sample_rate);
148
149 return 0;
150 }
151
152 static int codec2_read_header(AVFormatContext *s)
153 {
154 AVStream *st = avformat_new_stream(s, NULL);
155 int ret, version;
156
157 if (!st) {
158 return AVERROR(ENOMEM);
159 }
160
161 if (avio_rb24(s->pb) != CODEC2_MAGIC) {
162 av_log(s, AV_LOG_ERROR, "not a .c2 file\n");
163 return AVERROR_INVALIDDATA;
164 }
165
166 ret = ff_alloc_extradata(st->codecpar, CODEC2_EXTRADATA_SIZE);
167 if (ret) {
168 return ret;
169 }
170
171 ret = ffio_read_size(s->pb, st->codecpar->extradata, CODEC2_EXTRADATA_SIZE);
172 if (ret < 0) {
173 return ret;
174 }
175
176 version = AV_RB16(st->codecpar->extradata);
177 if ((version >> 8) != EXPECTED_CODEC2_MAJOR_VERSION) {
178 avpriv_report_missing_feature(s, "Major version %i", version >> 8);
179 return AVERROR_PATCHWELCOME;
180 }
181
182 ffformatcontext(s)->data_offset = CODEC2_HEADER_SIZE;
183
184 return codec2_read_header_common(s, st);
185 }
186
187 static int codec2_read_packet(AVFormatContext *s, AVPacket *pkt)
188 {
189 Codec2Context *c2 = s->priv_data;
190 AVStream *st = s->streams[0];
191 int ret, size, n, block_align, frame_size;
192
193 block_align = st->codecpar->block_align;
194 frame_size = st->codecpar->frame_size;
195
196 if (block_align <= 0 || frame_size <= 0 || c2->frames_per_packet <= 0) {
197 return AVERROR(EINVAL);
198 }
199
200 //try to read desired number of frames, compute n from to actual number of bytes read
201 if (c2->frames_per_packet > INT_MAX / block_align)
202 return AVERROR(EINVAL);
203 size = c2->frames_per_packet * block_align;
204 ret = av_get_packet(s->pb, pkt, size);
205 if (ret < 0) {
206 return ret;
207 }
208
209 //only set duration - compute_pkt_fields() and ff_pcm_read_seek() takes care of everything else
210 //tested by spamming the seek functionality in ffplay
211 n = ret / block_align;
212 pkt->duration = (int64_t)n * frame_size;
213
214 return ret;
215 }
216
217 static int codec2_write_header(AVFormatContext *s)
218 {
219 AVStream *st = s->streams[0];
220
221 if (st->codecpar->extradata_size != CODEC2_EXTRADATA_SIZE) {
222 av_log(s, AV_LOG_ERROR, ".c2 files require exactly %i bytes of extradata (got %i)\n",
223 CODEC2_EXTRADATA_SIZE, st->codecpar->extradata_size);
224 return AVERROR(EINVAL);
225 }
226
227 avio_wb24(s->pb, CODEC2_MAGIC);
228 avio_write(s->pb, st->codecpar->extradata, CODEC2_EXTRADATA_SIZE);
229
230 return 0;
231 }
232
233 static int codec2raw_read_header(AVFormatContext *s)
234 {
235 Codec2Context *c2 = s->priv_data;
236 AVStream *st;
237 int ret;
238
239 if (c2->mode < 0) {
240 //FIXME: using a default value of -1 for mandatory options is an incredibly ugly hack
241 av_log(s, AV_LOG_ERROR, "-mode must be set in order to make sense of raw codec2 files\n");
242 return AVERROR(EINVAL);
243 }
244
245 st = avformat_new_stream(s, NULL);
246 if (!st) {
247 return AVERROR(ENOMEM);
248 }
249
250 ret = ff_alloc_extradata(st->codecpar, CODEC2_EXTRADATA_SIZE);
251 if (ret) {
252 return ret;
253 }
254
255 codec2_make_extradata(st->codecpar->extradata, c2->mode);
256
257 return codec2_read_header_common(s, st);
258 }
259
260 //transcoding report2074.c2 to wav went from 7.391s to 5.322s with -frames_per_packet 1000 compared to default, same sha1sum
261 #define FRAMES_PER_PACKET \
262 { "frames_per_packet", "Number of frames to read at a time. Higher = faster decoding, lower granularity", \
263 offsetof(Codec2Context, frames_per_packet), AV_OPT_TYPE_INT, {.i64 = 1}, 1, INT_MAX, AV_OPT_FLAG_DECODING_PARAM}
264
265 static const AVOption codec2_options[] = {
266 FRAMES_PER_PACKET,
267 { NULL },
268 };
269
270 static const AVOption codec2raw_options[] = {
271 CODEC2_AVOPTIONS("codec2 mode [mandatory]", Codec2Context, -1, -1, AV_OPT_FLAG_DECODING_PARAM),
272 FRAMES_PER_PACKET,
273 { NULL },
274 };
275
276 static const AVClass codec2_demux_class = {
277 .class_name = "codec2 demuxer",
278 .item_name = av_default_item_name,
279 .option = codec2_options,
280 .version = LIBAVUTIL_VERSION_INT,
281 .category = AV_CLASS_CATEGORY_DEMUXER,
282 };
283
284 static const AVClass codec2raw_demux_class = {
285 .class_name = "codec2raw demuxer",
286 .item_name = av_default_item_name,
287 .option = codec2raw_options,
288 .version = LIBAVUTIL_VERSION_INT,
289 .category = AV_CLASS_CATEGORY_DEMUXER,
290 };
291
292 #if CONFIG_CODEC2_DEMUXER
293 const FFInputFormat ff_codec2_demuxer = {
294 .p.name = "codec2",
295 .p.long_name = NULL_IF_CONFIG_SMALL("codec2 .c2 demuxer"),
296 .p.extensions = "c2",
297 .p.flags = AVFMT_GENERIC_INDEX,
298 .p.priv_class = &codec2_demux_class,
299 .priv_data_size = sizeof(Codec2Context),
300 .read_probe = codec2_probe,
301 .read_header = codec2_read_header,
302 .read_packet = codec2_read_packet,
303 .read_seek = ff_pcm_read_seek,
304 .raw_codec_id = AV_CODEC_ID_CODEC2,
305 };
306 #endif
307
308 #if CONFIG_CODEC2_MUXER
309 const FFOutputFormat ff_codec2_muxer = {
310 .p.name = "codec2",
311 .p.long_name = NULL_IF_CONFIG_SMALL("codec2 .c2 muxer"),
312 .p.extensions = "c2",
313 .p.audio_codec = AV_CODEC_ID_CODEC2,
314 .p.video_codec = AV_CODEC_ID_NONE,
315 .p.subtitle_codec = AV_CODEC_ID_NONE,
316 .p.flags = AVFMT_NOTIMESTAMPS,
317 .flags_internal = FF_OFMT_FLAG_MAX_ONE_OF_EACH |
318 FF_OFMT_FLAG_ONLY_DEFAULT_CODECS,
319 .write_header = codec2_write_header,
320 .write_packet = ff_raw_write_packet,
321 };
322 #endif
323
324 #if CONFIG_CODEC2RAW_DEMUXER
325 const FFInputFormat ff_codec2raw_demuxer = {
326 .p.name = "codec2raw",
327 .p.long_name = NULL_IF_CONFIG_SMALL("raw codec2 demuxer"),
328 .p.flags = AVFMT_GENERIC_INDEX,
329 .p.priv_class = &codec2raw_demux_class,
330 .priv_data_size = sizeof(Codec2Context),
331 .read_header = codec2raw_read_header,
332 .read_packet = codec2_read_packet,
333 .read_seek = ff_pcm_read_seek,
334 .raw_codec_id = AV_CODEC_ID_CODEC2,
335 };
336 #endif
337