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 <memory.h>
23 #include "libavcodec/codec2utils.h"
24 #include "libavutil/intreadwrite.h"
25 #include "avio_internal.h"
26 #include "avformat.h"
27 #include "internal.h"
28 #include "rawdec.h"
29 #include "rawenc.h"
30 #include "pcm.h"
31
32 #define CODEC2_HEADER_SIZE 7
33 #define CODEC2_MAGIC 0xC0DEC2
34
35 //the lowest version we should ever run across is 0.8
36 //we may run across later versions as the format evolves
37 #define EXPECTED_CODEC2_MAJOR_VERSION 0
38 #define EXPECTED_CODEC2_MINOR_VERSION 8
39
40 typedef struct {
41 const AVClass *class;
42 int mode;
43 int frames_per_packet;
44 } Codec2Context;
45
codec2_probe(const AVProbeData * p)46 static int codec2_probe(const AVProbeData *p)
47 {
48 //must start wih C0 DE C2
49 if (AV_RB24(p->buf) != CODEC2_MAGIC) {
50 return 0;
51 }
52
53 //no .c2 files prior to 0.8
54 //be strict about major version while we're at it
55 if (p->buf[3] != EXPECTED_CODEC2_MAJOR_VERSION ||
56 p->buf[4] < EXPECTED_CODEC2_MINOR_VERSION) {
57 return 0;
58 }
59
60 //32 bits of identification -> low score
61 return AVPROBE_SCORE_EXTENSION + 1;
62 }
63
64 //Mimics codec2_samples_per_frame()
codec2_mode_frame_size(AVFormatContext * s,int mode)65 static int codec2_mode_frame_size(AVFormatContext *s, int mode)
66 {
67 int frame_size_table[CODEC2_MODE_MAX+1] = {
68 160, // 3200
69 160, // 2400
70 320, // 1600
71 320, // 1400
72 320, // 1300
73 320, // 1200
74 320, // 700
75 320, // 700B
76 320, // 700C
77 };
78
79 if (mode < 0 || mode > CODEC2_MODE_MAX) {
80 av_log(s, AV_LOG_ERROR, "unknown codec2 mode %i, can't find frame_size\n", mode);
81 return 0;
82 } else {
83 return frame_size_table[mode];
84 }
85 }
86
87 //Mimics (codec2_bits_per_frame()+7)/8
codec2_mode_block_align(AVFormatContext * s,int mode)88 static int codec2_mode_block_align(AVFormatContext *s, int mode)
89 {
90 int block_align_table[CODEC2_MODE_MAX+1] = {
91 8, // 3200
92 6, // 2400
93 8, // 1600
94 7, // 1400
95 7, // 1300
96 6, // 1200
97 4, // 700
98 4, // 700B
99 4, // 700C
100 };
101
102 if (mode < 0 || mode > CODEC2_MODE_MAX) {
103 av_log(s, AV_LOG_ERROR, "unknown codec2 mode %i, can't find block_align\n", mode);
104 return 0;
105 } else {
106 return block_align_table[mode];
107 }
108 }
109
110 //Computes bitrate from mode, with frames rounded up to the nearest octet.
111 //So 700 bit/s (28 bits/frame) becomes 800 bits/s (32 bits/frame).
codec2_mode_bit_rate(AVFormatContext * s,int mode)112 static int codec2_mode_bit_rate(AVFormatContext *s, int mode)
113 {
114 int frame_size = codec2_mode_frame_size(s, mode);
115 int block_align = codec2_mode_block_align(s, mode);
116
117 if (frame_size <= 0 || block_align <= 0) {
118 return 0;
119 }
120
121 return 8 * 8000 * block_align / frame_size;
122 }
123
codec2_read_header_common(AVFormatContext * s,AVStream * st)124 static int codec2_read_header_common(AVFormatContext *s, AVStream *st)
125 {
126 int mode = codec2_mode_from_extradata(st->codecpar->extradata);
127
128 st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
129 st->codecpar->codec_id = AV_CODEC_ID_CODEC2;
130 st->codecpar->sample_rate = 8000;
131 st->codecpar->channels = 1;
132 st->codecpar->format = AV_SAMPLE_FMT_S16;
133 st->codecpar->channel_layout = AV_CH_LAYOUT_MONO;
134 st->codecpar->bit_rate = codec2_mode_bit_rate(s, mode);
135 st->codecpar->frame_size = codec2_mode_frame_size(s, mode);
136 st->codecpar->block_align = codec2_mode_block_align(s, mode);
137
138 if (st->codecpar->bit_rate <= 0 ||
139 st->codecpar->frame_size <= 0 ||
140 st->codecpar->block_align <= 0) {
141 return AVERROR_INVALIDDATA;
142 }
143
144 avpriv_set_pts_info(st, 64, 1, st->codecpar->sample_rate);
145
146 return 0;
147 }
148
codec2_read_header(AVFormatContext * s)149 static int codec2_read_header(AVFormatContext *s)
150 {
151 AVStream *st = avformat_new_stream(s, NULL);
152 int ret, version;
153
154 if (!st) {
155 return AVERROR(ENOMEM);
156 }
157
158 if (avio_rb24(s->pb) != CODEC2_MAGIC) {
159 av_log(s, AV_LOG_ERROR, "not a .c2 file\n");
160 return AVERROR_INVALIDDATA;
161 }
162
163 ret = ff_alloc_extradata(st->codecpar, CODEC2_EXTRADATA_SIZE);
164 if (ret) {
165 return ret;
166 }
167
168 ret = ffio_read_size(s->pb, st->codecpar->extradata, CODEC2_EXTRADATA_SIZE);
169 if (ret < 0) {
170 return ret;
171 }
172
173 version = AV_RB16(st->codecpar->extradata);
174 if ((version >> 8) != EXPECTED_CODEC2_MAJOR_VERSION) {
175 avpriv_report_missing_feature(s, "Major version %i", version >> 8);
176 return AVERROR_PATCHWELCOME;
177 }
178
179 s->internal->data_offset = CODEC2_HEADER_SIZE;
180
181 return codec2_read_header_common(s, st);
182 }
183
codec2_read_packet(AVFormatContext * s,AVPacket * pkt)184 static int codec2_read_packet(AVFormatContext *s, AVPacket *pkt)
185 {
186 Codec2Context *c2 = s->priv_data;
187 AVStream *st = s->streams[0];
188 int ret, size, n, block_align, frame_size;
189
190 block_align = st->codecpar->block_align;
191 frame_size = st->codecpar->frame_size;
192
193 if (block_align <= 0 || frame_size <= 0 || c2->frames_per_packet <= 0) {
194 return AVERROR(EINVAL);
195 }
196
197 //try to read desired number of frames, compute n from to actual number of bytes read
198 size = c2->frames_per_packet * block_align;
199 ret = av_get_packet(s->pb, pkt, size);
200 if (ret < 0) {
201 return ret;
202 }
203
204 //only set duration - compute_pkt_fields() and ff_pcm_read_seek() takes care of everything else
205 //tested by spamming the seek functionality in ffplay
206 n = ret / block_align;
207 pkt->duration = n * frame_size;
208
209 return ret;
210 }
211
codec2_write_header(AVFormatContext * s)212 static int codec2_write_header(AVFormatContext *s)
213 {
214 AVStream *st;
215
216 if (s->nb_streams != 1 || s->streams[0]->codecpar->codec_id != AV_CODEC_ID_CODEC2) {
217 av_log(s, AV_LOG_ERROR, ".c2 files must have exactly one codec2 stream\n");
218 return AVERROR(EINVAL);
219 }
220
221 st = s->streams[0];
222
223 if (st->codecpar->extradata_size != CODEC2_EXTRADATA_SIZE) {
224 av_log(s, AV_LOG_ERROR, ".c2 files require exactly %i bytes of extradata (got %i)\n",
225 CODEC2_EXTRADATA_SIZE, st->codecpar->extradata_size);
226 return AVERROR(EINVAL);
227 }
228
229 avio_wb24(s->pb, CODEC2_MAGIC);
230 avio_write(s->pb, st->codecpar->extradata, CODEC2_EXTRADATA_SIZE);
231
232 return 0;
233 }
234
codec2raw_read_header(AVFormatContext * s)235 static int codec2raw_read_header(AVFormatContext *s)
236 {
237 Codec2Context *c2 = s->priv_data;
238 AVStream *st;
239 int ret;
240
241 if (c2->mode < 0) {
242 //FIXME: using a default value of -1 for mandatory options is an incredibly ugly hack
243 av_log(s, AV_LOG_ERROR, "-mode must be set in order to make sense of raw codec2 files\n");
244 return AVERROR(EINVAL);
245 }
246
247 st = avformat_new_stream(s, NULL);
248 if (!st) {
249 return AVERROR(ENOMEM);
250 }
251
252 ret = ff_alloc_extradata(st->codecpar, CODEC2_EXTRADATA_SIZE);
253 if (ret) {
254 return ret;
255 }
256
257 s->internal->data_offset = 0;
258 codec2_make_extradata(st->codecpar->extradata, c2->mode);
259
260 return codec2_read_header_common(s, st);
261 }
262
263 //transcoding report2074.c2 to wav went from 7.391s to 5.322s with -frames_per_packet 1000 compared to default, same sha1sum
264 #define FRAMES_PER_PACKET \
265 { "frames_per_packet", "Number of frames to read at a time. Higher = faster decoding, lower granularity", \
266 offsetof(Codec2Context, frames_per_packet), AV_OPT_TYPE_INT, {.i64 = 1}, 1, INT_MAX, AV_OPT_FLAG_DECODING_PARAM}
267
268 static const AVOption codec2_options[] = {
269 FRAMES_PER_PACKET,
270 { NULL },
271 };
272
273 static const AVOption codec2raw_options[] = {
274 CODEC2_AVOPTIONS("codec2 mode [mandatory]", Codec2Context, -1, -1, AV_OPT_FLAG_DECODING_PARAM),
275 FRAMES_PER_PACKET,
276 { NULL },
277 };
278
279 static const AVClass codec2_mux_class = {
280 .class_name = "codec2 muxer",
281 .item_name = av_default_item_name,
282 .version = LIBAVUTIL_VERSION_INT,
283 .category = AV_CLASS_CATEGORY_DEMUXER,
284 };
285
286 static const AVClass codec2_demux_class = {
287 .class_name = "codec2 demuxer",
288 .item_name = av_default_item_name,
289 .option = codec2_options,
290 .version = LIBAVUTIL_VERSION_INT,
291 .category = AV_CLASS_CATEGORY_DEMUXER,
292 };
293
294 static const AVClass codec2raw_demux_class = {
295 .class_name = "codec2raw demuxer",
296 .item_name = av_default_item_name,
297 .option = codec2raw_options,
298 .version = LIBAVUTIL_VERSION_INT,
299 .category = AV_CLASS_CATEGORY_DEMUXER,
300 };
301
302 #if CONFIG_CODEC2_DEMUXER
303 AVInputFormat ff_codec2_demuxer = {
304 .name = "codec2",
305 .long_name = NULL_IF_CONFIG_SMALL("codec2 .c2 demuxer"),
306 .priv_data_size = sizeof(Codec2Context),
307 .extensions = "c2",
308 .read_probe = codec2_probe,
309 .read_header = codec2_read_header,
310 .read_packet = codec2_read_packet,
311 .read_seek = ff_pcm_read_seek,
312 .flags = AVFMT_GENERIC_INDEX,
313 .raw_codec_id = AV_CODEC_ID_CODEC2,
314 .priv_class = &codec2_demux_class,
315 };
316 #endif
317
318 #if CONFIG_CODEC2_MUXER
319 AVOutputFormat ff_codec2_muxer = {
320 .name = "codec2",
321 .long_name = NULL_IF_CONFIG_SMALL("codec2 .c2 muxer"),
322 .priv_data_size = sizeof(Codec2Context),
323 .extensions = "c2",
324 .audio_codec = AV_CODEC_ID_CODEC2,
325 .video_codec = AV_CODEC_ID_NONE,
326 .write_header = codec2_write_header,
327 .write_packet = ff_raw_write_packet,
328 .flags = AVFMT_NOTIMESTAMPS,
329 .priv_class = &codec2_mux_class,
330 };
331 #endif
332
333 #if CONFIG_CODEC2RAW_DEMUXER
334 AVInputFormat ff_codec2raw_demuxer = {
335 .name = "codec2raw",
336 .long_name = NULL_IF_CONFIG_SMALL("raw codec2 demuxer"),
337 .priv_data_size = sizeof(Codec2Context),
338 .read_header = codec2raw_read_header,
339 .read_packet = codec2_read_packet,
340 .read_seek = ff_pcm_read_seek,
341 .flags = AVFMT_GENERIC_INDEX,
342 .raw_codec_id = AV_CODEC_ID_CODEC2,
343 .priv_class = &codec2raw_demux_class,
344 };
345 #endif
346