+ /* 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) {
+ shared_ptr<const Film> film = _film.lock ();
+ assert (film);
+ LOG_ERROR ("avcodec_decode_audio4 failed (%1)", decode_result);
+ return;
+ }
+
+ if (frame_finished) {
+
+ if (_audio_position == 0) {
+ /* Where we are in the source, in seconds */
+ double const pts = av_q2d (_format_context->streams[copy_packet.stream_index]->time_base)
+ * av_frame_get_best_effort_timestamp(_frame) + _pts_offset;
+
+ if (pts > 0) {
+ /* Emit some silence */
+ shared_ptr<AudioBuffers> silence (
+ new AudioBuffers (
+ _ffmpeg_content->audio_channels(),
+ pts * _ffmpeg_content->content_audio_frame_rate()
+ )
+ );
+
+ silence->make_silent ();
+ audio (silence, _audio_position);
+ }
+ }
+
+ int const data_size = av_samples_get_buffer_size (
+ 0, audio_codec_context()->channels, _frame->nb_samples, audio_sample_format (), 1
+ );
+
+ audio (deinterleave_audio (_frame->data, data_size), _audio_position);
+ }
+
+ copy_packet.data += decode_result;
+ copy_packet.size -= decode_result;
+ }