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 "audio_buffers.h"
  45
  46 #include "i18n.h"
  47
  48 using std::cout;
  49 using std::string;
  50 using std::vector;
  51 using std::stringstream;
  52 using std::list;
  53 using std::min;
  54 using boost::shared_ptr;
  55 using boost::optional;
  56 using boost::dynamic_pointer_cast;
  57 using libdcp::Size;
  58
  59 FFmpegDecoder::FFmpegDecoder (shared_ptr<const Film> f, shared_ptr<const FFmpegContent> c, bool video, bool audio)
  60         : Decoder (f)
  61         , VideoDecoder (f)
  62         , AudioDecoder (f)
  63         , SubtitleDecoder (f)
  64         , FFmpeg (c)
  65         , _subtitle_codec_context (0)
  66         , _subtitle_codec (0)
  67         , _decode_video (video)
  68         , _decode_audio (audio)
  69         , _pts_offset (0)
  70         , _just_sought (false)
  71 {
  72         setup_subtitle ();
  73
  74         if (video && audio && c->audio_stream() && c->first_video() && c->audio_stream()->first_audio) {
  75                 _pts_offset = compute_pts_offset (c->first_video().get(), c->audio_stream()->first_audio.get(), c->video_frame_rate());
  76         }
  77 }
  78
  79 double
  80 FFmpegDecoder::compute_pts_offset (double first_video, double first_audio, float video_frame_rate)
  81 {
  82         double const old_first_video = first_video;
  83
  84         /* Round the first video to a frame boundary */
  85         if (fabs (rint (first_video * video_frame_rate) - first_video * video_frame_rate) > 1e-6) {
  86                 first_video = ceil (first_video * video_frame_rate) / video_frame_rate;
  87         }
  88
  89         /* Compute the required offset (also removing any common start delay) */
  90         return first_video - old_first_video - min (first_video, first_audio);
  91 }
  92
  93 FFmpegDecoder::~FFmpegDecoder ()
  94 {
  95         boost::mutex::scoped_lock lm (_mutex);
  96
  97         if (_subtitle_codec_context) {
  98                 avcodec_close (_subtitle_codec_context);
  99         }
 100 }
 101
 102 void
 103 FFmpegDecoder::pass ()
 104 {
 105         int r = av_read_frame (_format_context, &_packet);
 106
 107         if (r < 0) {
 108                 if (r != AVERROR_EOF) {
 109                         /* Maybe we should fail here, but for now we'll just finish off instead */
 110                         char buf[256];
 111                         av_strerror (r, buf, sizeof(buf));
 112                         shared_ptr<const Film> film = _film.lock ();
 113                         assert (film);
 114                         film->log()->log (String::compose (N_("error on av_read_frame (%1) (%2)"), buf, r));
 115                 }
 116
 117                 /* Get any remaining frames */
 118
 119                 _packet.data = 0;
 120                 _packet.size = 0;
 121
 122                 /* XXX: should we reset _packet.data and size after each *_decode_* call? */
 123
 124                 if (_decode_video) {
 125                         while (decode_video_packet ()) {}
 126                 }
 127
 128                 if (_ffmpeg_content->audio_stream() && _decode_audio) {
 129                         decode_audio_packet ();
 130                 }
 131
 132                 /* Stop us being asked for any more data */
 133                 _video_position = _ffmpeg_content->video_length ();
 134                 _audio_position = _ffmpeg_content->audio_length ();
 135                 return;
 136         }
 137
 138         avcodec_get_frame_defaults (_frame);
 139
 140         if (_packet.stream_index == _video_stream && _decode_video) {
 141                 decode_video_packet ();
 142         } else if (_ffmpeg_content->audio_stream() && _packet.stream_index == _ffmpeg_content->audio_stream()->id && _decode_audio) {
 143                 decode_audio_packet ();
 144         } else if (_ffmpeg_content->subtitle_stream() && _packet.stream_index == _ffmpeg_content->subtitle_stream()->id) {
 145                 decode_subtitle_packet ();
 146         }
 147
 148         av_free_packet (&_packet);
 149 }
 150
 151 /** @param data pointer to array of pointers to buffers.
 152  *  Only the first buffer will be used for non-planar data, otherwise there will be one per channel.
 153  */
 154 shared_ptr<AudioBuffers>
 155 FFmpegDecoder::deinterleave_audio (uint8_t** data, int size)
 156 {
 157         assert (_ffmpeg_content->audio_channels());
 158         assert (bytes_per_audio_sample());
 159
 160         /* Deinterleave and convert to float */
 161
 162         assert ((size % (bytes_per_audio_sample() * _ffmpeg_content->audio_channels())) == 0);
 163
 164         int const total_samples = size / bytes_per_audio_sample();
 165         int const frames = total_samples / _ffmpeg_content->audio_channels();
 166         shared_ptr<AudioBuffers> audio (new AudioBuffers (_ffmpeg_content->audio_channels(), frames));
 167
 168         switch (audio_sample_format()) {
 169         case AV_SAMPLE_FMT_S16:
 170         {
 171                 int16_t* p = reinterpret_cast<int16_t *> (data[0]);
 172                 int sample = 0;
 173                 int channel = 0;
 174                 for (int i = 0; i < total_samples; ++i) {
 175                         audio->data(channel)[sample] = float(*p++) / (1 << 15);
 176
 177                         ++channel;
 178                         if (channel == _ffmpeg_content->audio_channels()) {
 179                                 channel = 0;
 180                                 ++sample;
 181                         }
 182                 }
 183         }
 184         break;
 185
 186         case AV_SAMPLE_FMT_S16P:
 187         {
 188                 int16_t** p = reinterpret_cast<int16_t **> (data);
 189                 for (int i = 0; i < _ffmpeg_content->audio_channels(); ++i) {
 190                         for (int j = 0; j < frames; ++j) {
 191                                 audio->data(i)[j] = static_cast<float>(p[i][j]) / (1 << 15);
 192                         }
 193                 }
 194         }
 195         break;
 196
 197         case AV_SAMPLE_FMT_S32:
 198         {
 199                 int32_t* p = reinterpret_cast<int32_t *> (data[0]);
 200                 int sample = 0;
 201                 int channel = 0;
 202                 for (int i = 0; i < total_samples; ++i) {
 203                         audio->data(channel)[sample] = static_cast<float>(*p++) / (1 << 31);
 204
 205                         ++channel;
 206                         if (channel == _ffmpeg_content->audio_channels()) {
 207                                 channel = 0;
 208                                 ++sample;
 209                         }
 210                 }
 211         }
 212         break;
 213
 214         case AV_SAMPLE_FMT_FLT:
 215         {
 216                 float* p = reinterpret_cast<float*> (data[0]);
 217                 int sample = 0;
 218                 int channel = 0;
 219                 for (int i = 0; i < total_samples; ++i) {
 220                         audio->data(channel)[sample] = *p++;
 221
 222                         ++channel;
 223                         if (channel == _ffmpeg_content->audio_channels()) {
 224                                 channel = 0;
 225                                 ++sample;
 226                         }
 227                 }
 228         }
 229         break;
 230
 231         case AV_SAMPLE_FMT_FLTP:
 232         {
 233                 float** p = reinterpret_cast<float**> (data);
 234                 for (int i = 0; i < _ffmpeg_content->audio_channels(); ++i) {
 235                         memcpy (audio->data(i), p[i], frames * sizeof(float));
 236                 }
 237         }
 238         break;
 239
 240         default:
 241                 throw DecodeError (String::compose (_("Unrecognised audio sample format (%1)"), static_cast<int> (audio_sample_format())));
 242         }
 243
 244         return audio;
 245 }
 246
 247 AVSampleFormat
 248 FFmpegDecoder::audio_sample_format () const
 249 {
 250         if (!_ffmpeg_content->audio_stream()) {
 251                 return (AVSampleFormat) 0;
 252         }
 253
 254         return audio_codec_context()->sample_fmt;
 255 }
 256
 257 int
 258 FFmpegDecoder::bytes_per_audio_sample () const
 259 {
 260         return av_get_bytes_per_sample (audio_sample_format ());
 261 }
 262
 263 void
 264 FFmpegDecoder::seek (VideoContent::Frame frame, bool accurate)
 265 {
 266         double const time_base = av_q2d (_format_context->streams[_video_stream]->time_base);
 267         int64_t const vt = frame / (_ffmpeg_content->video_frame_rate() * time_base);
 268         av_seek_frame (_format_context, _video_stream, vt, AVSEEK_FLAG_BACKWARD);
 269
 270         avcodec_flush_buffers (video_codec_context());
 271         if (_subtitle_codec_context) {
 272                 avcodec_flush_buffers (_subtitle_codec_context);
 273         }
 274
 275         _just_sought = true;
 276
 277         if (frame == 0) {
 278                 /* We're already there; from here on we can only seek non-zero amounts */
 279                 return;
 280         }
 281
 282         if (accurate) {
 283                 while (1) {
 284                         int r = av_read_frame (_format_context, &_packet);
 285                         if (r < 0) {
 286                                 return;
 287                         }
 288
 289                         avcodec_get_frame_defaults (_frame);
 290
 291                         if (_packet.stream_index == _video_stream) {
 292                                 int finished = 0;
 293                                 int const r = avcodec_decode_video2 (video_codec_context(), _frame, &finished, &_packet);
 294                                 if (r >= 0 && finished) {
 295                                         int64_t const bet = av_frame_get_best_effort_timestamp (_frame);
 296                                         if (bet >= vt) {
 297                                                 _video_position = rint (
 298                                                         (bet * time_base + _pts_offset) * _ffmpeg_content->video_frame_rate()
 299                                                         );
 300                                                 av_free_packet (&_packet);
 301                                                 break;
 302                                         }
 303                                 }
 304                         }
 305
 306                         av_free_packet (&_packet);
 307                 }
 308         }
 309 }
 310
 311 void
 312 FFmpegDecoder::decode_audio_packet ()
 313 {
 314         /* Audio packets can contain multiple frames, so we may have to call avcodec_decode_audio4
 315            several times.
 316         */
 317
 318         AVPacket copy_packet = _packet;
 319
 320         while (copy_packet.size > 0) {
 321
 322                 int frame_finished;
 323                 int const decode_result = avcodec_decode_audio4 (audio_codec_context(), _frame, &frame_finished, &copy_packet);
 324                 if (decode_result >= 0) {
 325                         if (frame_finished) {
 326
 327                                 if (_audio_position == 0) {
 328                                         /* Where we are in the source, in seconds */
 329                                         double const pts = av_q2d (_format_context->streams[copy_packet.stream_index]->time_base)
 330                                                 * av_frame_get_best_effort_timestamp(_frame) - _pts_offset;
 331
 332                                         if (pts > 0) {
 333                                                 /* Emit some silence */
 334                                                 shared_ptr<AudioBuffers> silence (
 335                                                         new AudioBuffers (
 336                                                                 _ffmpeg_content->audio_channels(),
 337                                                                 pts * _ffmpeg_content->content_audio_frame_rate()
 338                                                                 )
 339                                                         );
 340
 341                                                 silence->make_silent ();
 342                                                 audio (silence, _audio_position);
 343                                         }
 344                                 }
 345
 346                                 copy_packet.data += decode_result;
 347                                 copy_packet.size -= decode_result;
 348                         }
 349                 }
 350         }
 351 }
 352
 353 bool
 354 FFmpegDecoder::decode_video_packet ()
 355 {
 356         int frame_finished;
 357         if (avcodec_decode_video2 (video_codec_context(), _frame, &frame_finished, &_packet) < 0 || !frame_finished) {
 358                 return false;
 359         }
 360
 361         boost::mutex::scoped_lock lm (_filter_graphs_mutex);
 362
 363         shared_ptr<FilterGraph> graph;
 364
 365         list<shared_ptr<FilterGraph> >::iterator i = _filter_graphs.begin();
 366         while (i != _filter_graphs.end() && !(*i)->can_process (libdcp::Size (_frame->width, _frame->height), (AVPixelFormat) _frame->format)) {
 367                 ++i;
 368         }
 369
 370         if (i == _filter_graphs.end ()) {
 371                 shared_ptr<const Film> film = _film.lock ();
 372                 assert (film);
 373
 374                 graph.reset (new FilterGraph (_ffmpeg_content, libdcp::Size (_frame->width, _frame->height), (AVPixelFormat) _frame->format));
 375                 _filter_graphs.push_back (graph);
 376
 377                 film->log()->log (String::compose (N_("New graph for %1x%2, pixel format %3"), _frame->width, _frame->height, _frame->format));
 378         } else {
 379                 graph = *i;
 380         }
 381
 382         list<shared_ptr<Image> > images = graph->process (_frame);
 383
 384         string post_process = Filter::ffmpeg_strings (_ffmpeg_content->filters()).second;
 385
 386         for (list<shared_ptr<Image> >::iterator i = images.begin(); i != images.end(); ++i) {
 387
 388                 shared_ptr<Image> image = *i;
 389                 if (!post_process.empty ()) {
 390                         image = image->post_process (post_process, true);
 391                 }
 392
 393                 int64_t const bet = av_frame_get_best_effort_timestamp (_frame);
 394                 if (bet != AV_NOPTS_VALUE) {
 395
 396                         double const pts = bet * av_q2d (_format_context->streams[_video_stream]->time_base) - _pts_offset;
 397
 398                         if (_just_sought) {
 399                                 /* We just did a seek, so disable any attempts to correct for where we
 400                                    are / should be.
 401                                 */
 402                                 _video_position = rint (pts * _ffmpeg_content->video_frame_rate ());
 403                                 _just_sought = false;
 404                         }
 405
 406                         double const next = _video_position / _ffmpeg_content->video_frame_rate();
 407                         double const one_frame = 1 / _ffmpeg_content->video_frame_rate ();
 408                         double delta = pts - next;
 409
 410                         while (delta > one_frame) {
 411                                 /* This PTS is more than one frame forward in time of where we think we should be; emit
 412                                    a black frame.
 413                                 */
 414                                 boost::shared_ptr<Image> black (
 415                                         new Image (
 416                                                 static_cast<AVPixelFormat> (_frame->format),
 417                                                 libdcp::Size (video_codec_context()->width, video_codec_context()->height),
 418                                                 true
 419                                                 )
 420                                         );
 421
 422                                 black->make_black ();
 423                                 video (image, false, _video_position);
 424                                 delta -= one_frame;
 425                         }
 426
 427                         if (delta > -one_frame) {
 428                                 /* This PTS is within a frame of being right; emit this (otherwise it will be dropped) */
 429                                 video (image, false, _video_position);
 430                         }
 431
 432                 } else {
 433                         shared_ptr<const Film> film = _film.lock ();
 434                         assert (film);
 435                         film->log()->log ("Dropping frame without PTS");
 436                 }
 437         }
 438
 439         return true;
 440 }
 441
 442
 443 void
 444 FFmpegDecoder::setup_subtitle ()
 445 {
 446         boost::mutex::scoped_lock lm (_mutex);
 447
 448         if (!_ffmpeg_content->subtitle_stream() || _ffmpeg_content->subtitle_stream()->id >= int (_format_context->nb_streams)) {
 449                 return;
 450         }
 451
 452         _subtitle_codec_context = _format_context->streams[_ffmpeg_content->subtitle_stream()->id]->codec;
 453         _subtitle_codec = avcodec_find_decoder (_subtitle_codec_context->codec_id);
 454
 455         if (_subtitle_codec == 0) {
 456                 throw DecodeError (_("could not find subtitle decoder"));
 457         }
 458
 459         if (avcodec_open2 (_subtitle_codec_context, _subtitle_codec, 0) < 0) {
 460                 throw DecodeError (N_("could not open subtitle decoder"));
 461         }
 462 }
 463
 464 bool
 465 FFmpegDecoder::done () const
 466 {
 467         bool const vd = !_decode_video || (_video_position >= _ffmpeg_content->video_length());
 468         bool const ad = !_decode_audio || !_ffmpeg_content->audio_stream() || (_audio_position >= _ffmpeg_content->audio_length());
 469         return vd && ad;
 470 }
 471
 472 void
 473 FFmpegDecoder::decode_subtitle_packet ()
 474 {
 475         int got_subtitle;
 476         AVSubtitle sub;
 477         if (avcodec_decode_subtitle2 (_subtitle_codec_context, &sub, &got_subtitle, &_packet) < 0 || !got_subtitle) {
 478                 return;
 479         }
 480
 481         /* Sometimes we get an empty AVSubtitle, which is used by some codecs to
 482            indicate that the previous subtitle should stop.
 483         */
 484         if (sub.num_rects <= 0) {
 485                 subtitle (shared_ptr<Image> (), dcpomatic::Rect<double> (), 0, 0);
 486                 return;
 487         } else if (sub.num_rects > 1) {
 488                 throw DecodeError (_("multi-part subtitles not yet supported"));
 489         }
 490
 491         /* Subtitle PTS in seconds (within the source, not taking into account any of the
 492            source that we may have chopped off for the DCP)
 493         */
 494         double const packet_time = static_cast<double> (sub.pts) / AV_TIME_BASE;
 495
 496         /* hence start time for this sub */
 497         Time const from = (packet_time + (double (sub.start_display_time) / 1e3)) * TIME_HZ;
 498         Time const to = (packet_time + (double (sub.end_display_time) / 1e3)) * TIME_HZ;
 499
 500         AVSubtitleRect const * rect = sub.rects[0];
 501
 502         if (rect->type != SUBTITLE_BITMAP) {
 503                 throw DecodeError (_("non-bitmap subtitles not yet supported"));
 504         }
 505
 506         shared_ptr<Image> image (new Image (PIX_FMT_RGBA, libdcp::Size (rect->w, rect->h), true));
 507
 508         /* Start of the first line in the subtitle */
 509         uint8_t* sub_p = rect->pict.data[0];
 510         /* sub_p looks up into a RGB palette which is here */
 511         uint32_t const * palette = (uint32_t *) rect->pict.data[1];
 512         /* Start of the output data */
 513         uint32_t* out_p = (uint32_t *) image->data()[0];
 514
 515         for (int y = 0; y < rect->h; ++y) {
 516                 uint8_t* sub_line_p = sub_p;
 517                 uint32_t* out_line_p = out_p;
 518                 for (int x = 0; x < rect->w; ++x) {
 519                         *out_line_p++ = palette[*sub_line_p++];
 520                 }
 521                 sub_p += rect->pict.linesize[0];
 522                 out_p += image->stride()[0] / sizeof (uint32_t);
 523         }
 524
 525         libdcp::Size const vs = _ffmpeg_content->video_size ();
 526
 527         subtitle (
 528                 image,
 529                 dcpomatic::Rect<double> (
 530                         static_cast<double> (rect->x) / vs.width,
 531                         static_cast<double> (rect->y) / vs.height,
 532                         static_cast<double> (rect->w) / vs.width,
 533                         static_cast<double> (rect->h) / vs.height
 534                         ),
 535                 from,
 536                 to
 537                 );
 538
 539
 540         avsubtitle_free (&sub);
 541 }