FFmpeg: libavcodec/libopusenc.c Source File

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libopusenc.c

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1 /*

2 * Opus encoder using libopus

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 */

22 #include <opus.h>

23 #include <opus_multistream.h>

25 #include "libavutil/opt.h"

26 #include "avcodec.h"

27 #include "bytestream.h"

28 #include "internal.h"

29 #include "libopus.h"

30 #include "vorbis.h"

31 #include "audio_frame_queue.h"

33 typedef struct LibopusEncOpts {

34 int vbr;

35 int application;

36 int packet_loss;

37 int complexity;

38 float frame_duration;

39 int packet_size;

40 int max_bandwidth;

41 } LibopusEncOpts;

43 typedef struct LibopusEncContext {

44 AVClass *class;

45 OpusMSEncoder *enc;

46 int stream_count;

47 uint8_t *samples;

48 LibopusEncOpts opts;

49 AudioFrameQueue afq;

50 } LibopusEncContext;

52 static const uint8_t opus_coupled_streams[8] = {

53 0, 1, 1, 2, 2, 2, 2, 3

54 };

56 /* Opus internal to Vorbis channel order mapping written in the header */

57 static const uint8_t opus_vorbis_channel_map[8][8] = {

58 { 0 },

59 { 0, 1 },

60 { 0, 2, 1 },

61 { 0, 1, 2, 3 },

62 { 0, 4, 1, 2, 3 },

63 { 0, 4, 1, 2, 3, 5 },

64 { 0, 4, 1, 2, 3, 5, 6 },

65 { 0, 6, 1, 2, 3, 4, 5, 7 },

66 };

68 /* libavcodec to libopus channel order mapping, passed to libopus */

69 static const uint8_t libavcodec_libopus_channel_map[8][8] = {

70 { 0 },

71 { 0, 1 },

72 { 0, 1, 2 },

73 { 0, 1, 2, 3 },

74 { 0, 1, 3, 4, 2 },

75 { 0, 1, 4, 5, 2, 3 },

76 { 0, 1, 5, 6, 2, 4, 3 },

77 { 0, 1, 6, 7, 4, 5, 2, 3 },

78 };

80 static void libopus_write_header(AVCodecContext *avctx, int stream_count,

81 int coupled_stream_count,

82 const uint8_t *channel_mapping)

83 {

84 uint8_t *p = avctx->extradata;

85 int channels = avctx->channels;

87 bytestream_put_buffer(&p, "OpusHead", 8);

88 bytestream_put_byte(&p, 1); /* Version */

89 bytestream_put_byte(&p, channels);

90 bytestream_put_le16(&p, avctx->delay); /* Lookahead samples at 48kHz */

91 bytestream_put_le32(&p, avctx->sample_rate); /* Original sample rate */

92 bytestream_put_le16(&p, 0); /* Gain of 0dB is recommended. */

94 /* Channel mapping */

95 if (channels > 2) {

96 bytestream_put_byte(&p, channels <= 8 ? 1 : 255);

97 bytestream_put_byte(&p, stream_count);

98 bytestream_put_byte(&p, coupled_stream_count);

99 bytestream_put_buffer(&p, channel_mapping, channels);

100 } else {

101 bytestream_put_byte(&p, 0);

102 }

103 }

104

105 static int libopus_configure_encoder(AVCodecContext *avctx, OpusMSEncoder *enc,

106 LibopusEncOpts *opts)

107 {

108 int ret;

109

110 if (avctx->global_quality) {

111 av_log(avctx, AV_LOG_ERROR,

112 "Quality-based encoding not supported, "

113 "please specify a bitrate and VBR setting.\n");

114 return AVERROR(EINVAL);

115 }

116

117 ret = opus_multistream_encoder_ctl(enc, OPUS_SET_BITRATE(avctx->bit_rate));

118 if (ret != OPUS_OK) {

119 av_log(avctx, AV_LOG_ERROR,

120 "Failed to set bitrate: %s\n", opus_strerror(ret));

121 return ret;

122 }

123

124 ret = opus_multistream_encoder_ctl(enc,

125 OPUS_SET_COMPLEXITY(opts->complexity));

126 if (ret != OPUS_OK)

127 av_log(avctx, AV_LOG_WARNING,

128 "Unable to set complexity: %s\n", opus_strerror(ret));

129

130 ret = opus_multistream_encoder_ctl(enc, OPUS_SET_VBR(!!opts->vbr));

131 if (ret != OPUS_OK)

132 av_log(avctx, AV_LOG_WARNING,

133 "Unable to set VBR: %s\n", opus_strerror(ret));

134

135 ret = opus_multistream_encoder_ctl(enc,

136 OPUS_SET_VBR_CONSTRAINT(opts->vbr == 2));

137 if (ret != OPUS_OK)

138 av_log(avctx, AV_LOG_WARNING,

139 "Unable to set constrained VBR: %s\n", opus_strerror(ret));

140

141 ret = opus_multistream_encoder_ctl(enc,

142 OPUS_SET_PACKET_LOSS_PERC(opts->packet_loss));

143 if (ret != OPUS_OK)

144 av_log(avctx, AV_LOG_WARNING,

145 "Unable to set expected packet loss percentage: %s\n",

146 opus_strerror(ret));

147

148 if (avctx->cutoff) {

149 ret = opus_multistream_encoder_ctl(enc,

150 OPUS_SET_MAX_BANDWIDTH(opts->max_bandwidth));

151 if (ret != OPUS_OK)

152 av_log(avctx, AV_LOG_WARNING,

153 "Unable to set maximum bandwidth: %s\n", opus_strerror(ret));

154 }

155

156 return OPUS_OK;

157 }

158

159 static av_cold int libopus_encode_init(AVCodecContext *avctx)

160 {

161 LibopusEncContext *opus = avctx->priv_data;

162 const uint8_t *channel_mapping;

163 OpusMSEncoder *enc;

164 int ret = OPUS_OK;

165 int coupled_stream_count, header_size, frame_size;

166

167 coupled_stream_count = opus_coupled_streams[avctx->channels - 1];

168 opus->stream_count = avctx->channels - coupled_stream_count;

169 channel_mapping = libavcodec_libopus_channel_map[avctx->channels - 1];

170

171 /* FIXME: Opus can handle up to 255 channels. However, the mapping for

172 * anything greater than 8 is undefined. */

173 if (avctx->channels > 8)

174 av_log(avctx, AV_LOG_WARNING,

175 "Channel layout undefined for %d channels.\n", avctx->channels);

176

177 if (!avctx->bit_rate) {

178 /* Sane default copied from opusenc */

179 avctx->bit_rate = 64000 * opus->stream_count +

180 32000 * coupled_stream_count;

181 av_log(avctx, AV_LOG_WARNING,

182 "No bit rate set. Defaulting to %d bps.\n", avctx->bit_rate);

183 }

184

185 if (avctx->bit_rate < 500 || avctx->bit_rate > 256000 * avctx->channels) {

186 av_log(avctx, AV_LOG_ERROR, "The bit rate %d bps is unsupported. "

187 "Please choose a value between 500 and %d.\n", avctx->bit_rate,

188 256000 * avctx->channels);

189 return AVERROR(EINVAL);

190 }

191

192 frame_size = opus->opts.frame_duration * 48000 / 1000;

193 switch (frame_size) {

194 case 120:

195 case 240:

196 if (opus->opts.application != OPUS_APPLICATION_RESTRICTED_LOWDELAY)

197 av_log(avctx, AV_LOG_WARNING,

198 "LPC mode cannot be used with a frame duration of less "

199 "than 10ms. Enabling restricted low-delay mode.\n"

200 "Use a longer frame duration if this is not what you want.\n");

201 /* Frame sizes less than 10 ms can only use MDCT mode, so switching to

202 * RESTRICTED_LOWDELAY avoids an unnecessary extra 2.5ms lookahead. */

203 opus->opts.application = OPUS_APPLICATION_RESTRICTED_LOWDELAY;

204 case 480:

205 case 960:

206 case 1920:

207 case 2880:

208 opus->opts.packet_size =

209 avctx->frame_size = frame_size * avctx->sample_rate / 48000;

210 break;

211 default:

212 av_log(avctx, AV_LOG_ERROR, "Invalid frame duration: %g.\n"

213 "Frame duration must be exactly one of: 2.5, 5, 10, 20, 40 or 60.\n",

214 opus->opts.frame_duration);

215 return AVERROR(EINVAL);

216 }

217

218 if (avctx->compression_level < 0 || avctx->compression_level > 10) {

219 av_log(avctx, AV_LOG_WARNING,

220 "Compression level must be in the range 0 to 10. "

221 "Defaulting to 10.\n");

222 opus->opts.complexity = 10;

223 } else {

224 opus->opts.complexity = avctx->compression_level;

225 }

226

227 if (avctx->cutoff) {

228 switch (avctx->cutoff) {

229 case 4000:

230 opus->opts.max_bandwidth = OPUS_BANDWIDTH_NARROWBAND;

231 break;

232 case 6000:

233 opus->opts.max_bandwidth = OPUS_BANDWIDTH_MEDIUMBAND;

234 break;

235 case 8000:

236 opus->opts.max_bandwidth = OPUS_BANDWIDTH_WIDEBAND;

237 break;

238 case 12000:

239 opus->opts.max_bandwidth = OPUS_BANDWIDTH_SUPERWIDEBAND;

240 break;

241 case 20000:

242 opus->opts.max_bandwidth = OPUS_BANDWIDTH_FULLBAND;

243 break;

244 default:

245 av_log(avctx, AV_LOG_WARNING,

246 "Invalid frequency cutoff: %d. Using default maximum bandwidth.\n"

247 "Cutoff frequency must be exactly one of: 4000, 6000, 8000, 12000 or 20000.\n",

248 avctx->cutoff);

249 avctx->cutoff = 0;

250 }

251 }

252

253 enc = opus_multistream_encoder_create(avctx->sample_rate, avctx->channels,

254 opus->stream_count,

255 coupled_stream_count,

256 channel_mapping,

257 opus->opts.application, &ret);

258 if (ret != OPUS_OK) {

259 av_log(avctx, AV_LOG_ERROR,

260 "Failed to create encoder: %s\n", opus_strerror(ret));

261 return ff_opus_error_to_averror(ret);

262 }

263

264 ret = libopus_configure_encoder(avctx, enc, &opus->opts);

265 if (ret != OPUS_OK) {

266 ret = ff_opus_error_to_averror(ret);

267 goto fail;

268 }

269

270 header_size = 19 + (avctx->channels > 2 ? 2 + avctx->channels : 0);

271 avctx->extradata = av_malloc(header_size + FF_INPUT_BUFFER_PADDING_SIZE);

272 if (!avctx->extradata) {

273 av_log(avctx, AV_LOG_ERROR, "Failed to allocate extradata.\n");

274 ret = AVERROR(ENOMEM);

275 goto fail;

276 }

277 avctx->extradata_size = header_size;

278

279 opus->samples = av_mallocz(frame_size * avctx->channels *

280 av_get_bytes_per_sample(avctx->sample_fmt));

281 if (!opus->samples) {

282 av_log(avctx, AV_LOG_ERROR, "Failed to allocate samples buffer.\n");

283 ret = AVERROR(ENOMEM);

284 goto fail;

285 }

286

287 ret = opus_multistream_encoder_ctl(enc, OPUS_GET_LOOKAHEAD(&avctx->delay));

288 if (ret != OPUS_OK)

289 av_log(avctx, AV_LOG_WARNING,

290 "Unable to get number of lookahead samples: %s\n",

291 opus_strerror(ret));

292

293 libopus_write_header(avctx, opus->stream_count, coupled_stream_count,

294 opus_vorbis_channel_map[avctx->channels - 1]);

295

296 ff_af_queue_init(avctx, &opus->afq);

297

298 opus->enc = enc;

299

300 return 0;

301

302 fail:

303 opus_multistream_encoder_destroy(enc);

304 av_freep(&avctx->extradata);

305 return ret;

306 }

307

308 static int libopus_encode(AVCodecContext *avctx, AVPacket *avpkt,

309 const AVFrame *frame, int *got_packet_ptr)

310 {

311 LibopusEncContext *opus = avctx->priv_data;

312 const int sample_size = avctx->channels *

313 av_get_bytes_per_sample(avctx->sample_fmt);

314 uint8_t *audio;

315 int ret;

316 int discard_padding;

317

318 if (frame) {

319 ff_af_queue_add(&opus->afq, frame);

320 if (frame->nb_samples < opus->opts.packet_size) {

321 audio = opus->samples;

322 memcpy(audio, frame->data[0], frame->nb_samples * sample_size);

323 } else

324 audio = frame->data[0];

325 } else {

326 if (!opus->afq.remaining_samples)

327 return 0;

328 audio = opus->samples;

329 memset(audio, 0, opus->opts.packet_size * sample_size);

330 }

331

332 /* Maximum packet size taken from opusenc in opus-tools. 60ms packets

333 * consist of 3 frames in one packet. The maximum frame size is 1275

334 * bytes along with the largest possible packet header of 7 bytes. */

335 if ((ret = ff_alloc_packet2(avctx, avpkt, (1275 * 3 + 7) * opus->stream_count)) < 0)

336 return ret;

337

338 if (avctx->sample_fmt == AV_SAMPLE_FMT_FLT)

339 ret = opus_multistream_encode_float(opus->enc, (float *)audio,

340 opus->opts.packet_size,

341 avpkt->data, avpkt->size);

342 else

343 ret = opus_multistream_encode(opus->enc, (opus_int16 *)audio,

344 opus->opts.packet_size,

345 avpkt->data, avpkt->size);

346

347 if (ret < 0) {

348 av_log(avctx, AV_LOG_ERROR,

349 "Error encoding frame: %s\n", opus_strerror(ret));

350 return ff_opus_error_to_averror(ret);

351 }

352

353 av_shrink_packet(avpkt, ret);

354

355 ff_af_queue_remove(&opus->afq, opus->opts.packet_size,

356 &avpkt->pts, &avpkt->duration);

357

358 discard_padding = opus->opts.packet_size - avpkt->duration;

359 // Check if subtraction resulted in an overflow

360 if ((discard_padding < opus->opts.packet_size) != (avpkt->duration > 0)) {

361 av_free_packet(avpkt);

362 av_free(avpkt);

363 return AVERROR(EINVAL);

364 }

365 if (discard_padding > 0) {

366 uint8_t* side_data = av_packet_new_side_data(avpkt,

367 AV_PKT_DATA_SKIP_SAMPLES,

368 10);

369 if(side_data == NULL) {

370 av_free_packet(avpkt);

371 av_free(avpkt);

372 return AVERROR(ENOMEM);

373 }

374 AV_WL32(side_data + 4, discard_padding);

375 }

376

377 *got_packet_ptr = 1;

378

379 return 0;

380 }

381

382 static av_cold int libopus_encode_close(AVCodecContext *avctx)

383 {

384 LibopusEncContext *opus = avctx->priv_data;

385

386 opus_multistream_encoder_destroy(opus->enc);

387

388 ff_af_queue_close(&opus->afq);

389

390 av_freep(&opus->samples);

391 av_freep(&avctx->extradata);

392

393 return 0;

394 }

395

396 #define OFFSET(x) offsetof(LibopusEncContext, opts.x)

397 #define FLAGS AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_ENCODING_PARAM

398 static const AVOption libopus_options[] = {

399 { "application", "Intended application type", OFFSET(application), AV_OPT_TYPE_INT, { .i64 = OPUS_APPLICATION_AUDIO }, OPUS_APPLICATION_VOIP, OPUS_APPLICATION_RESTRICTED_LOWDELAY, FLAGS, "application" },

400 { "voip", "Favor improved speech intelligibility", 0, AV_OPT_TYPE_CONST, { .i64 = OPUS_APPLICATION_VOIP }, 0, 0, FLAGS, "application" },

401 { "audio", "Favor faithfulness to the input", 0, AV_OPT_TYPE_CONST, { .i64 = OPUS_APPLICATION_AUDIO }, 0, 0, FLAGS, "application" },

402 { "lowdelay", "Restrict to only the lowest delay modes", 0, AV_OPT_TYPE_CONST, { .i64 = OPUS_APPLICATION_RESTRICTED_LOWDELAY }, 0, 0, FLAGS, "application" },

403 { "frame_duration", "Duration of a frame in milliseconds", OFFSET(frame_duration), AV_OPT_TYPE_FLOAT, { .dbl = 20.0 }, 2.5, 60.0, FLAGS },

404 { "packet_loss", "Expected packet loss percentage", OFFSET(packet_loss), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 100, FLAGS },

405 { "vbr", "Variable bit rate mode", OFFSET(vbr), AV_OPT_TYPE_INT, { .i64 = 1 }, 0, 2, FLAGS, "vbr" },

406 { "off", "Use constant bit rate", 0, AV_OPT_TYPE_CONST, { .i64 = 0 }, 0, 0, FLAGS, "vbr" },

407 { "on", "Use variable bit rate", 0, AV_OPT_TYPE_CONST, { .i64 = 1 }, 0, 0, FLAGS, "vbr" },

408 { "constrained", "Use constrained VBR", 0, AV_OPT_TYPE_CONST, { .i64 = 2 }, 0, 0, FLAGS, "vbr" },

409 { NULL },

410 };

411

412 static const AVClass libopus_class = {

413 .class_name = "libopus",

414 .item_name = av_default_item_name,