Try again to sort out the audio padding / alignment.

[dcpomatic.git] / src / lib / ffmpeg_decoder.cc

diff --git a/src/lib/ffmpeg_decoder.cc b/src/lib/ffmpeg_decoder.cc
index c74fee008458a53914daaf38ea4244f4166d5d31..5eb32a0147f14e2d277474f6fe46c8fbbaf650ee 100644 (file)
--- a/src/lib/ffmpeg_decoder.cc
+++ b/src/lib/ffmpeg_decoder.cc
@@ -66,8 +66,6 @@ FFmpegDecoder::FFmpegDecoder (boost::shared_ptr<const FilmState> s, boost::share
        , _audio_codec (0)
        , _subtitle_codec_context (0)
        , _subtitle_codec (0)
-       , _first_video_pts (-1)
-       , _first_audio_pts (-1)
 {
        setup_general ();
        setup_video ();
@@ -213,6 +211,7 @@ bool
 FFmpegDecoder::do_pass ()
 {
        int r = av_read_frame (_format_context, &_packet);
+       
        if (r < 0) {
                if (r != AVERROR_EOF) {
                        throw DecodeError ("error on av_read_frame");
@@ -245,10 +244,12 @@ FFmpegDecoder::do_pass ()
                return true;
        }
 
+       double const pts_seconds = av_q2d (_format_context->streams[_packet.stream_index]->time_base) * _packet.pts;
+       
        if (_packet.stream_index == _video_stream) {
 
-               if (_first_video_pts == -1) {
-                       _first_video_pts = _packet.pts;
+               if (!_first_video) {
+                       _first_video = pts_seconds;
                }
                
                int frame_finished;
@@ -256,39 +257,33 @@ FFmpegDecoder::do_pass ()
                        process_video (_frame);
                }
 
-       } else if (_audio_stream >= 0 && _packet.stream_index == _audio_stream && _opt->decode_audio && (_first_video_pts != -1 && _packet.pts > _first_video_pts)) {
+       } else if (_audio_stream >= 0 && _packet.stream_index == _audio_stream && _opt->decode_audio && _first_video && _first_video.get() <= pts_seconds) {
 
-               /* Note: We only decode audio if we've had our first video packet through, and if this
-                  packet comes after it.  Until then it is thrown away.
+               /* Note: 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_audio_pts == -1) {
-                       _first_audio_pts = _packet.pts;
-
+               
+               if (!_first_audio) {
+                       _first_audio = pts_seconds;
+                       
                        /* This is our first audio packet, and if we've arrived here we must have had our
                           first video packet.  Push some silence to make up the gap between our first
                           video packet and our first audio.
                        */
                        
-                       AVStream* v = _format_context->streams[_video_stream];
-                       AVStream* a = _format_context->streams[_audio_stream];
+                       /* frames of silence that we must push */
+                       int const s = rint ((_first_audio.get() - _first_video.get()) * audio_sample_rate ());
                        
-                       assert (v->time_base.num == a->time_base.num);
-                       assert (v->time_base.den == a->time_base.den);
-
-                       /* samples of silence that we must push */
-                       int const s = rint (av_q2d (v->time_base) * (_first_audio_pts - _first_video_pts) * audio_sample_rate ());
-
                        _log->log (
                                String::compose (
-                                       "First video at %1, first audio at %2, pushing %3 samples of silence",
-                                       _first_video_pts, _first_audio_pts, s
+                                       "First video at %1, first audio at %2, pushing %3 frames of silence for %4 channels (%5 bytes per sample)",
+                                       _first_video.get(), _first_audio.get(), s, audio_channels(), bytes_per_audio_sample()
                                        )
                                );
-
+                       
                        /* hence bytes */
                        int const b = s * audio_channels() * bytes_per_audio_sample();
-
+                       
                        /* XXX: this assumes that it won't be too much, and there are shaky assumptions
                           that all sound representations are silent with memset()ed zero data.
                        */
@@ -296,7 +291,7 @@ FFmpegDecoder::do_pass ()
                        memset (silence, 0, b);
                        process_audio (silence, b);
                }
-
+               
                avcodec_get_frame_defaults (_frame);
                
                int frame_finished;
@@ -304,11 +299,11 @@ FFmpegDecoder::do_pass ()
                        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 == _fs->audio_channels());
                        process_audio (_frame->data[0], data_size);
                }
-
+                       
        } else if (_subtitle_stream >= 0 && _packet.stream_index == _subtitle_stream && _opt->decode_subtitles) {
 
                int got_subtitle;