+ return {};
+ }
+
+ return *stream;
+}
+
+
+void
+FFmpegDecoder::process_audio_frame (shared_ptr<FFmpegAudioStream> stream, int stream_index, int64_t packet_pts)
+{
+ auto data = deinterleave_audio (stream);
+
+ ContentTime ct;
+ if (_frame->pts == AV_NOPTS_VALUE) {
+ /* In some streams we see not every frame coming through with a timestamp; for those
+ that have AV_NOPTS_VALUE we need to work out the timestamp ourselves. This is
+ particularly noticeable with TrueHD streams (see #1111).
+ */
+ if (_next_time[stream_index]) {
+ ct = *_next_time[stream_index];
+ }
+ } else {
+ ct = ContentTime::from_seconds (
+ _frame->best_effort_timestamp *
+ av_q2d (stream->stream(_format_context)->time_base))
+ + _pts_offset;
+ }
+
+ _next_time[stream_index] = ct + ContentTime::from_frames(data->frames(), stream->frame_rate());
+
+ if (ct < ContentTime()) {
+ /* Discard audio data that comes before time 0 */
+ auto const remove = min (int64_t(data->frames()), (-ct).frames_ceil(double(stream->frame_rate())));
+ data->move (data->frames() - remove, remove, 0);
+ data->set_frames (data->frames() - remove);
+ ct += ContentTime::from_frames (remove, stream->frame_rate());
+ }
+
+ if (ct < ContentTime()) {
+ LOG_WARNING (
+ "Crazy timestamp %1 for %2 samples in stream %3 packet pts %4 (ts=%5 tb=%6, off=%7)",
+ to_string(ct),
+ data->frames(),
+ stream_index,
+ packet_pts,
+ _frame->best_effort_timestamp,
+ av_q2d(stream->stream(_format_context)->time_base),
+ to_string(_pts_offset)
+ );
+ }
+
+ /* Give this data provided there is some, and its time is sane */
+ if (ct >= ContentTime() && data->frames() > 0) {
+ audio->emit (film(), stream, data, ct);
+ }
+}
+
+
+void
+FFmpegDecoder::decode_audio_packet (AVPacket* packet)
+{
+ int const stream_index = packet->stream_index;
+ auto stream = audio_stream_from_index (stream_index);
+ if (!stream) {