+int
+FFmpegDecoder::bytes_per_audio_sample () const
+{
+ return av_get_bytes_per_sample (audio_sample_format ());
+}
+
+void
+FFmpegDecoder::filter_and_emit_video (AVFrame* frame)
+{
+ boost::mutex::scoped_lock lm (_filter_graphs_mutex);
+
+ shared_ptr<FilterGraph> graph;
+
+ list<shared_ptr<FilterGraph> >::iterator i = _filter_graphs.begin();
+ while (i != _filter_graphs.end() && !(*i)->can_process (libdcp::Size (frame->width, frame->height), (AVPixelFormat) frame->format)) {
+ ++i;
+ }
+
+ if (i == _filter_graphs.end ()) {
+ graph.reset (new FilterGraph (_film, this, libdcp::Size (frame->width, frame->height), (AVPixelFormat) frame->format));
+ _filter_graphs.push_back (graph);
+ _film->log()->log (String::compose (N_("New graph for %1x%2, pixel format %3"), frame->width, frame->height, frame->format));
+ } else {
+ graph = *i;
+ }
+
+ list<shared_ptr<Image> > images = graph->process (frame);
+
+ for (list<shared_ptr<Image> >::iterator i = images.begin(); i != images.end(); ++i) {
+ emit_video (*i, frame_time ());
+ }
+}
+
+bool
+FFmpegDecoder::seek (double p)
+{
+ return do_seek (p, false);
+}
+
+bool
+FFmpegDecoder::seek_to_last ()
+{
+ /* This AVSEEK_FLAG_BACKWARD in do_seek is a bit of a hack; without it, if we ask for a seek to the same place as last time
+ (used when we change decoder parameters and want to re-fetch the frame) we end up going forwards rather than
+ staying in the same place.
+ */
+ return do_seek (last_source_time(), true);
+}
+
+bool
+FFmpegDecoder::do_seek (double p, bool backwards)
+{
+ int64_t const vt = p / av_q2d (_format_context->streams[_video_stream]->time_base);
+
+ int const r = av_seek_frame (_format_context, _video_stream, vt, backwards ? AVSEEK_FLAG_BACKWARD : 0);
+
+ avcodec_flush_buffers (_video_codec_context);
+ if (_subtitle_codec_context) {
+ avcodec_flush_buffers (_subtitle_codec_context);
+ }
+
+ return r < 0;
+}
+
+void
+FFmpegDecoder::out_with_sync ()
+{
+ /* Where we are in the output, in seconds */
+ double const out_pts_seconds = video_frame() / frames_per_second();
+
+ /* Where we are in the source, in seconds */
+ double const source_pts_seconds = av_q2d (_format_context->streams[_packet.stream_index]->time_base)
+ * av_frame_get_best_effort_timestamp(_frame);
+
+ _film->log()->log (
+ String::compose (N_("Source video frame ready; source at %1, output at %2"), source_pts_seconds, out_pts_seconds),
+ Log::VERBOSE
+ );
+
+ if (!_first_video) {
+ _first_video = source_pts_seconds;
+ }
+
+ /* Difference between where we are and where we should be */
+ double const delta = source_pts_seconds - _first_video.get() - out_pts_seconds;
+ double const one_frame = 1 / frames_per_second();
+
+ /* Insert frames if required to get out_pts_seconds up to pts_seconds */
+ if (delta > one_frame) {
+ int const extra = rint (delta / one_frame);
+ for (int i = 0; i < extra; ++i) {
+ repeat_last_video ();
+ _film->log()->log (
+ String::compose (
+ N_("Extra video frame inserted at %1s; source frame %2, source PTS %3 (at %4 fps)"),
+ out_pts_seconds, video_frame(), source_pts_seconds, frames_per_second()
+ )
+ );
+ }
+ }
+
+ if (delta > -one_frame) {
+ /* Process this frame */
+ filter_and_emit_video (_frame);
+ } else {
+ /* Otherwise we are omitting a frame to keep things right */
+ _film->log()->log (String::compose (N_("Frame removed at %1s"), out_pts_seconds));
+ }
+}
+
+void
+FFmpegDecoder::film_changed (Film::Property p)
+{
+ switch (p) {
+ case Film::CROP:
+ case Film::FILTERS:
+ {
+ boost::mutex::scoped_lock lm (_filter_graphs_mutex);
+ _filter_graphs.clear ();
+ }
+ OutputChanged ();
+ break;
+
+ default:
+ break;
+ }
+}
+
+/** @return Length (in video frames) according to our content's header */
+ContentVideoFrame
+FFmpegDecoder::video_length () const
+{
+ return (double(_format_context->duration) / AV_TIME_BASE) * frames_per_second();
+}
+
+double
+FFmpegDecoder::frame_time () const
+{
+ return av_frame_get_best_effort_timestamp(_frame) * av_q2d (_format_context->streams[_video_stream]->time_base);
+}
+
+void
+FFmpegDecoder::decode_audio_packet ()
+{
+ /* Audio packets can contain multiple frames, so we may have to call avcodec_decode_audio4
+ several times.
+ */
+
+ AVPacket copy_packet = _packet;
+
+ while (copy_packet.size > 0) {
+
+ int frame_finished;
+ int const decode_result = avcodec_decode_audio4 (_audio_codec_context, _frame, &frame_finished, ©_packet);
+ if (decode_result >= 0 && frame_finished) {
+
+ /* Where we are in the source, in seconds */
+ double const source_pts_seconds = av_q2d (_format_context->streams[copy_packet.stream_index]->time_base)
+ * av_frame_get_best_effort_timestamp(_frame);
+
+ /* We only decode audio if we've had our first video packet through, and if it
+ was before this packet. Until then audio is thrown away.
+ */
+
+ if ((_first_video && _first_video.get() <= source_pts_seconds) || !_opt.decode_video) {
+
+ if (!_first_audio && _opt.decode_video) {
+ _first_audio = source_pts_seconds;
+
+ /* This is our first audio frame, and if we've arrived here we must have had our
+ first video frame. Push some silence to make up any gap between our first
+ video frame and our first audio.
+ */
+
+ /* frames of silence that we must push */
+ int const s = rint ((_first_audio.get() - _first_video.get()) * _ffmpeg_content->audio_frame_rate ());
+
+ _film->log()->log (
+ String::compose (
+ N_("First video at %1, first audio at %2, pushing %3 audio frames of silence for %4 channels (%5 bytes per sample)"),
+ _first_video.get(), _first_audio.get(), s, _ffmpeg_content->audio_channels(), bytes_per_audio_sample()
+ )
+ );
+
+ if (s) {
+ shared_ptr<AudioBuffers> audio (new AudioBuffers (_ffmpeg_content->audio_channels(), s));
+ audio->make_silent ();
+ Audio (audio);
+ }
+ }
+
+ int const data_size = av_samples_get_buffer_size (
+ 0, _audio_codec_context->channels, _frame->nb_samples, audio_sample_format (), 1
+ );
+
+ assert (_audio_codec_context->channels == _ffmpeg_content->audio_channels());
+ Audio (deinterleave_audio (_frame->data, data_size));
+ }
+ }
+
+ if (decode_result >= 0) {
+ copy_packet.data += decode_result;
+ copy_packet.size -= decode_result;
+ }
+ }
+}