src/lib/ffmpeg_decoder.cc

   1 /*
   2     Copyright (C) 2012 Carl Hetherington <cth@carlh.net>
   3
   4     This program is free software; you can redistribute it and/or modify
   5     it under the terms of the GNU General Public License as published by
   6     the Free Software Foundation; either version 2 of the License, or
   7     (at your option) any later version.
   8
   9     This program is distributed in the hope that it will be useful,
  10     but WITHOUT ANY WARRANTY; without even the implied warranty of
  11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12     GNU General Public License for more details.
  13
  14     You should have received a copy of the GNU General Public License
  15     along with this program; if not, write to the Free Software
  16     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  17
  18 */
  19
  20 /** @file  src/ffmpeg_decoder.cc
  21  *  @brief A decoder using FFmpeg to decode content.
  22  */
  23
  24 #include <stdexcept>
  25 #include <vector>
  26 #include <sstream>
  27 #include <iomanip>
  28 #include <iostream>
  29 #include <stdint.h>
  30 #include <boost/lexical_cast.hpp>
  31 #include <sndfile.h>
  32 extern "C" {
  33 #include <libavcodec/avcodec.h>
  34 #include <libavformat/avformat.h>
  35 }
  36 #include "film.h"
  37 #include "filter.h"
  38 #include "exceptions.h"
  39 #include "image.h"
  40 #include "util.h"
  41 #include "log.h"
  42 #include "ffmpeg_decoder.h"
  43 #include "filter_graph.h"
  44 #include "subtitle.h"
  45 #include "audio_buffers.h"
  46
  47 #include "i18n.h"
  48
  49 using std::cout;
  50 using std::string;
  51 using std::vector;
  52 using std::stringstream;
  53 using std::list;
  54 using std::min;
  55 using boost::shared_ptr;
  56 using boost::optional;
  57 using boost::dynamic_pointer_cast;
  58 using libdcp::Size;
  59
  60 FFmpegDecoder::FFmpegDecoder (shared_ptr<const Film> f, shared_ptr<const FFmpegContent> c, bool video, bool audio)
  61         : Decoder (f)
  62         , VideoDecoder (f)
  63         , AudioDecoder (f)
  64         , SubtitleDecoder (f)
  65         , FFmpeg (c)
  66         , _subtitle_codec_context (0)
  67         , _subtitle_codec (0)
  68         , _decode_video (video)
  69         , _decode_audio (audio)
  70         , _pts_offset (0)
  71         , _just_sought (false)
  72 {
  73         setup_subtitle ();
  74
  75         if (video && audio && c->audio_stream() && c->first_video() && c->audio_stream()->first_audio) {
  76                 _pts_offset = compute_pts_offset (c->first_video().get(), c->audio_stream()->first_audio.get(), c->video_frame_rate());
  77         }
  78 }
  79
  80 double
  81 FFmpegDecoder::compute_pts_offset (double first_video, double first_audio, float video_frame_rate)
  82 {
  83         double const old_first_video = first_video;
  84
  85         /* Round the first video to a frame boundary */
  86         if (fabs (rint (first_video * video_frame_rate) - first_video * video_frame_rate) > 1e-6) {
  87                 first_video = ceil (first_video * video_frame_rate) / video_frame_rate;
  88         }
  89
  90         /* Compute the required offset (also removing any common start delay) */
  91         return first_video - old_first_video - min (first_video, first_audio);
  92 }
  93
  94 FFmpegDecoder::~FFmpegDecoder ()
  95 {
  96         boost::mutex::scoped_lock lm (_mutex);
  97
  98         if (_subtitle_codec_context) {
  99                 avcodec_close (_subtitle_codec_context);
 100         }
 101 }
 102
 103 void
 104 FFmpegDecoder::pass ()
 105 {
 106         int r = av_read_frame (_format_context, &_packet);
 107
 108         if (r < 0) {
 109                 if (r != AVERROR_EOF) {
 110                         /* Maybe we should fail here, but for now we'll just finish off instead */
 111                         char buf[256];
 112                         av_strerror (r, buf, sizeof(buf));
 113                         shared_ptr<const Film> film = _film.lock ();
 114                         assert (film);
 115                         film->log()->log (String::compose (N_("error on av_read_frame (%1) (%2)"), buf, r));
 116                 }
 117
 118                 /* Get any remaining frames */
 119
 120                 _packet.data = 0;
 121                 _packet.size = 0;
 122
 123                 /* XXX: should we reset _packet.data and size after each *_decode_* call? */
 124
 125                 if (_decode_video) {
 126                         while (decode_video_packet ()) {}
 127                 }
 128
 129                 if (_ffmpeg_content->audio_stream() && _decode_audio) {
 130                         decode_audio_packet ();
 131                 }
 132
 133                 /* Stop us being asked for any more data */
 134                 _video_position = _ffmpeg_content->video_length ();
 135                 _audio_position = _ffmpeg_content->audio_length ();
 136                 return;
 137         }
 138
 139         avcodec_get_frame_defaults (_frame);
 140
 141         if (_packet.stream_index == _video_stream && _decode_video) {
 142                 decode_video_packet ();
 143         } else if (_ffmpeg_content->audio_stream() && _packet.stream_index == _ffmpeg_content->audio_stream()->id && _decode_audio) {
 144                 decode_audio_packet ();
 145         } else if (_ffmpeg_content->subtitle_stream() && _packet.stream_index == _ffmpeg_content->subtitle_stream()->id) {
 146                 decode_subtitle_packet ();
 147         }
 148
 149         av_free_packet (&_packet);
 150 }
 151
 152 /** @param data pointer to array of pointers to buffers.
 153  *  Only the first buffer will be used for non-planar data, otherwise there will be one per channel.
 154  */
 155 shared_ptr<AudioBuffers>
 156 FFmpegDecoder::deinterleave_audio (uint8_t** data, int size)
 157 {
 158         assert (_ffmpeg_content->audio_channels());
 159         assert (bytes_per_audio_sample());
 160
 161         /* Deinterleave and convert to float */
 162
 163         assert ((size % (bytes_per_audio_sample() * _ffmpeg_content->audio_channels())) == 0);
 164
 165         int const total_samples = size / bytes_per_audio_sample();
 166         int const frames = total_samples / _ffmpeg_content->audio_channels();
 167         shared_ptr<AudioBuffers> audio (new AudioBuffers (_ffmpeg_content->audio_channels(), frames));
 168
 169         switch (audio_sample_format()) {
 170         case AV_SAMPLE_FMT_S16:
 171         {
 172                 int16_t* p = reinterpret_cast<int16_t *> (data[0]);
 173                 int sample = 0;
 174                 int channel = 0;
 175                 for (int i = 0; i < total_samples; ++i) {
 176                         audio->data(channel)[sample] = float(*p++) / (1 << 15);
 177
 178                         ++channel;
 179                         if (channel == _ffmpeg_content->audio_channels()) {
 180                                 channel = 0;
 181                                 ++sample;
 182                         }
 183                 }
 184         }
 185         break;
 186
 187         case AV_SAMPLE_FMT_S16P:
 188         {
 189                 int16_t** p = reinterpret_cast<int16_t **> (data);
 190                 for (int i = 0; i < _ffmpeg_content->audio_channels(); ++i) {
 191                         for (int j = 0; j < frames; ++j) {
 192                                 audio->data(i)[j] = static_cast<float>(p[i][j]) / (1 << 15);
 193                         }
 194                 }
 195         }
 196         break;
 197
 198         case AV_SAMPLE_FMT_S32:
 199         {
 200                 int32_t* p = reinterpret_cast<int32_t *> (data[0]);
 201                 int sample = 0;
 202                 int channel = 0;
 203                 for (int i = 0; i < total_samples; ++i) {
 204                         audio->data(channel)[sample] = static_cast<float>(*p++) / (1 << 31);
 205
 206                         ++channel;
 207                         if (channel == _ffmpeg_content->audio_channels()) {
 208                                 channel = 0;
 209                                 ++sample;
 210                         }
 211                 }
 212         }
 213         break;
 214
 215         case AV_SAMPLE_FMT_FLT:
 216         {
 217                 float* p = reinterpret_cast<float*> (data[0]);
 218                 int sample = 0;
 219                 int channel = 0;
 220                 for (int i = 0; i < total_samples; ++i) {
 221                         audio->data(channel)[sample] = *p++;
 222
 223                         ++channel;
 224                         if (channel == _ffmpeg_content->audio_channels()) {
 225                                 channel = 0;
 226                                 ++sample;
 227                         }
 228                 }
 229         }
 230         break;
 231
 232         case AV_SAMPLE_FMT_FLTP:
 233         {
 234                 float** p = reinterpret_cast<float**> (data);
 235                 for (int i = 0; i < _ffmpeg_content->audio_channels(); ++i) {
 236                         memcpy (audio->data(i), p[i], frames * sizeof(float));
 237                 }
 238         }
 239         break;
 240
 241         default:
 242                 throw DecodeError (String::compose (_("Unrecognised audio sample format (%1)"), static_cast<int> (audio_sample_format())));
 243         }
 244
 245         return audio;
 246 }
 247
 248 AVSampleFormat
 249 FFmpegDecoder::audio_sample_format () const
 250 {
 251         if (!_ffmpeg_content->audio_stream()) {
 252                 return (AVSampleFormat) 0;
 253         }
 254
 255         return audio_codec_context()->sample_fmt;
 256 }
 257
 258 int
 259 FFmpegDecoder::bytes_per_audio_sample () const
 260 {
 261         return av_get_bytes_per_sample (audio_sample_format ());
 262 }
 263
 264 void
 265 FFmpegDecoder::seek (VideoContent::Frame frame, bool accurate)
 266 {
 267         double const time_base = av_q2d (_format_context->streams[_video_stream]->time_base);
 268         int64_t const vt = frame / (_ffmpeg_content->video_frame_rate() * time_base);
 269         av_seek_frame (_format_context, _video_stream, vt, AVSEEK_FLAG_BACKWARD);
 270
 271         avcodec_flush_buffers (video_codec_context());
 272         if (_subtitle_codec_context) {
 273                 avcodec_flush_buffers (_subtitle_codec_context);
 274         }
 275
 276         _just_sought = true;
 277
 278         if (frame == 0) {
 279                 /* We're already there; from here on we can only seek non-zero amounts */
 280                 return;
 281         }
 282
 283         if (accurate) {
 284                 while (1) {
 285                         int r = av_read_frame (_format_context, &_packet);
 286                         if (r < 0) {
 287                                 return;
 288                         }
 289
 290                         avcodec_get_frame_defaults (_frame);
 291
 292                         if (_packet.stream_index == _video_stream) {
 293                                 int finished = 0;
 294                                 int const r = avcodec_decode_video2 (video_codec_context(), _frame, &finished, &_packet);
 295                                 if (r >= 0 && finished) {
 296                                         int64_t const bet = av_frame_get_best_effort_timestamp (_frame);
 297                                         if (bet >= vt) {
 298                                                 _video_position = rint (
 299                                                         (bet * time_base + _pts_offset) * _ffmpeg_content->video_frame_rate()
 300                                                         );
 301                                                 av_free_packet (&_packet);
 302                                                 break;
 303                                         }
 304                                 }
 305                         }
 306
 307                         av_free_packet (&_packet);
 308                 }
 309         }
 310 }
 311
 312 void
 313 FFmpegDecoder::decode_audio_packet ()
 314 {
 315         /* Audio packets can contain multiple frames, so we may have to call avcodec_decode_audio4
 316            several times.
 317         */
 318
 319         AVPacket copy_packet = _packet;
 320
 321         while (copy_packet.size > 0) {
 322
 323                 int frame_finished;
 324                 int const decode_result = avcodec_decode_audio4 (audio_codec_context(), _frame, &frame_finished, &copy_packet);
 325                 if (decode_result >= 0) {
 326                         if (frame_finished) {
 327
 328                                 if (_audio_position == 0) {
 329                                         /* Where we are in the source, in seconds */
 330                                         double const pts = av_q2d (_format_context->streams[copy_packet.stream_index]->time_base)
 331                                                 * av_frame_get_best_effort_timestamp(_frame) - _pts_offset;
 332
 333                                         if (pts > 0) {
 334                                                 /* Emit some silence */
 335                                                 shared_ptr<AudioBuffers> silence (
 336                                                         new AudioBuffers (
 337                                                                 _ffmpeg_content->audio_channels(),
 338                                                                 pts * _ffmpeg_content->content_audio_frame_rate()
 339                                                                 )
 340                                                         );
 341
 342                                                 silence->make_silent ();
 343                                                 audio (silence, _audio_position);
 344                                         }
 345                                 }
 346
 347                                 copy_packet.data += decode_result;
 348                                 copy_packet.size -= decode_result;
 349                         }
 350                 }
 351         }
 352 }
 353
 354 bool
 355 FFmpegDecoder::decode_video_packet ()
 356 {
 357         int frame_finished;
 358         if (avcodec_decode_video2 (video_codec_context(), _frame, &frame_finished, &_packet) < 0 || !frame_finished) {
 359                 return false;
 360         }
 361
 362         boost::mutex::scoped_lock lm (_filter_graphs_mutex);
 363
 364         shared_ptr<FilterGraph> graph;
 365
 366         list<shared_ptr<FilterGraph> >::iterator i = _filter_graphs.begin();
 367         while (i != _filter_graphs.end() && !(*i)->can_process (libdcp::Size (_frame->width, _frame->height), (AVPixelFormat) _frame->format)) {
 368                 ++i;
 369         }
 370
 371         if (i == _filter_graphs.end ()) {
 372                 shared_ptr<const Film> film = _film.lock ();
 373                 assert (film);
 374
 375                 graph.reset (new FilterGraph (_ffmpeg_content, libdcp::Size (_frame->width, _frame->height), (AVPixelFormat) _frame->format));
 376                 _filter_graphs.push_back (graph);
 377
 378                 film->log()->log (String::compose (N_("New graph for %1x%2, pixel format %3"), _frame->width, _frame->height, _frame->format));
 379         } else {
 380                 graph = *i;
 381         }
 382
 383         list<shared_ptr<Image> > images = graph->process (_frame);
 384
 385         string post_process = Filter::ffmpeg_strings (_ffmpeg_content->filters()).second;
 386
 387         for (list<shared_ptr<Image> >::iterator i = images.begin(); i != images.end(); ++i) {
 388
 389                 shared_ptr<Image> image = *i;
 390                 if (!post_process.empty ()) {
 391                         image = image->post_process (post_process, true);
 392                 }
 393
 394                 int64_t const bet = av_frame_get_best_effort_timestamp (_frame);
 395                 if (bet != AV_NOPTS_VALUE) {
 396
 397                         double const pts = bet * av_q2d (_format_context->streams[_video_stream]->time_base) - _pts_offset;
 398
 399                         if (_just_sought) {
 400                                 /* We just did a seek, so disable any attempts to correct for where we
 401                                    are / should be.
 402                                 */
 403                                 _video_position = rint (pts * _ffmpeg_content->video_frame_rate ());
 404                                 _just_sought = false;
 405                         }
 406
 407                         double const next = _video_position / _ffmpeg_content->video_frame_rate();
 408                         double const one_frame = 1 / _ffmpeg_content->video_frame_rate ();
 409                         double delta = pts - next;
 410
 411                         while (delta > one_frame) {
 412                                 /* This PTS is more than one frame forward in time of where we think we should be; emit
 413                                    a black frame.
 414                                 */
 415                                 boost::shared_ptr<Image> black (
 416                                         new SimpleImage (
 417                                                 static_cast<AVPixelFormat> (_frame->format),
 418                                                 libdcp::Size (video_codec_context()->width, video_codec_context()->height),
 419                                                 true
 420                                                 )
 421                                         );
 422
 423                                 black->make_black ();
 424                                 video (image, false, _video_position);
 425                                 delta -= one_frame;
 426                         }
 427
 428                         if (delta > -one_frame) {
 429                                 /* This PTS is within a frame of being right; emit this (otherwise it will be dropped) */
 430                                 video (image, false, _video_position);
 431                         }
 432
 433                 } else {
 434                         shared_ptr<const Film> film = _film.lock ();
 435                         assert (film);
 436                         film->log()->log ("Dropping frame without PTS");
 437                 }
 438         }
 439
 440         return true;
 441 }
 442
 443
 444 void
 445 FFmpegDecoder::setup_subtitle ()
 446 {
 447         boost::mutex::scoped_lock lm (_mutex);
 448
 449         if (!_ffmpeg_content->subtitle_stream() || _ffmpeg_content->subtitle_stream()->id >= int (_format_context->nb_streams)) {
 450                 return;
 451         }
 452
 453         _subtitle_codec_context = _format_context->streams[_ffmpeg_content->subtitle_stream()->id]->codec;
 454         _subtitle_codec = avcodec_find_decoder (_subtitle_codec_context->codec_id);
 455
 456         if (_subtitle_codec == 0) {
 457                 throw DecodeError (_("could not find subtitle decoder"));
 458         }
 459
 460         if (avcodec_open2 (_subtitle_codec_context, _subtitle_codec, 0) < 0) {
 461                 throw DecodeError (N_("could not open subtitle decoder"));
 462         }
 463 }
 464
 465 bool
 466 FFmpegDecoder::done () const
 467 {
 468         bool const vd = !_decode_video || (_video_position >= _ffmpeg_content->video_length());
 469         bool const ad = !_decode_audio || !_ffmpeg_content->audio_stream() || (_audio_position >= _ffmpeg_content->audio_length());
 470         return vd && ad;
 471 }
 472
 473 void
 474 FFmpegDecoder::decode_subtitle_packet ()
 475 {
 476         int got_subtitle;
 477         AVSubtitle sub;
 478         if (avcodec_decode_subtitle2 (_subtitle_codec_context, &sub, &got_subtitle, &_packet) < 0 || !got_subtitle) {
 479                 return;
 480         }
 481
 482         /* Sometimes we get an empty AVSubtitle, which is used by some codecs to
 483            indicate that the previous subtitle should stop.
 484         */
 485         if (sub.num_rects > 0) {
 486                 shared_ptr<TimedSubtitle> ts;
 487                 try {
 488                         subtitle (shared_ptr<TimedSubtitle> (new TimedSubtitle (sub)));
 489                 } catch (...) {
 490                         /* some problem with the subtitle; we probably didn't understand it */
 491                 }
 492         } else {
 493                 subtitle (shared_ptr<TimedSubtitle> ());
 494         }
 495
 496         avsubtitle_free (&sub);
 497 }