Fix problems with subtitles when there is a non-zero PTS offset

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

diff --git a/src/lib/ffmpeg_decoder.cc b/src/lib/ffmpeg_decoder.cc
index d343ec317e14c6a32cc8f23574ff9613f698627b..475418d3d2be34f9d30a65b7cfcfcce5e3089f69 100644 (file)
--- a/src/lib/ffmpeg_decoder.cc
+++ b/src/lib/ffmpeg_decoder.cc
@@ -67,51 +67,9 @@ FFmpegDecoder::FFmpegDecoder (shared_ptr<const FFmpegContent> c, shared_ptr<Log>
        , SubtitleDecoder (c)
        , FFmpeg (c)
        , _log (log)
+       , _pts_offset (pts_offset (c->ffmpeg_audio_streams(), c->first_video(), c->video_frame_rate()))
 {
-       /* Audio and video frame PTS values may not start with 0.  We want
-          to fiddle them so that:
 
-          1.  One of them starts at time 0.
-          2.  The first video PTS value ends up on a frame boundary.
-
-          Then we remove big initial gaps in PTS and we allow our
-          insertion of black frames to work.
-
-          We will do:
-            audio_pts_to_use = audio_pts_from_ffmpeg + pts_offset;
-            video_pts_to_use = video_pts_from_ffmpeg + pts_offset;
-       */
-
-       /* First, make one of them start at 0 */
-
-       vector<shared_ptr<FFmpegAudioStream> > streams = c->ffmpeg_audio_streams ();
-
-       _pts_offset = ContentTime::min ();
-
-       if (c->first_video ()) {
-               _pts_offset = - c->first_video().get ();
-       }
-
-       BOOST_FOREACH (shared_ptr<FFmpegAudioStream> i, streams) {
-               if (i->first_audio) {
-                       _pts_offset = max (_pts_offset, - i->first_audio.get ());
-               }
-       }
-
-       /* If _pts_offset is positive we would be pushing things from a -ve PTS to be played.
-          I don't think we ever want to do that, as it seems things at -ve PTS are not meant
-          to be seen (use for alignment bars etc.); see mantis #418.
-       */
-       if (_pts_offset > ContentTime ()) {
-               _pts_offset = ContentTime ();
-       }
-
-       /* Now adjust so that the video pts starts on a frame */
-       if (c->first_video ()) {
-               ContentTime first_video = c->first_video().get() + _pts_offset;
-               ContentTime const old_first_video = first_video;
-               _pts_offset += first_video.round_up (c->video_frame_rate ()) - old_first_video;
-       }
 }
 
 void
@@ -457,7 +415,7 @@ FFmpegDecoder::decode_subtitle_packet ()
                period.to = sub_period.to.get() + _pts_offset;
        } else {
                /* We have to look up the `to' time in the stream's records */
-               period.to = ffmpeg_content()->subtitle_stream()->find_subtitle_to (sub_period.from);
+               period.to = ffmpeg_content()->subtitle_stream()->find_subtitle_to (period.from);
        }
 
        AVSubtitleRect const * rect = sub.rects[0];