Don't trust video timestamps from FFmpegDecoder.

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

diff --git a/src/lib/video_decoder.cc b/src/lib/video_decoder.cc
index 7a3a3e19b08b16220e1fd39c3deeefab47a575f4..19a99419753f402413652248a82e0df80a6905ee 100644 (file)
--- a/src/lib/video_decoder.cc
+++ b/src/lib/video_decoder.cc
@@ -54,12 +54,44 @@ VideoDecoder::VideoDecoder (Decoder* parent, shared_ptr<const Content> c)
  *  and so on.
  */
 void
-VideoDecoder::emit (shared_ptr<const Film> film, shared_ptr<const ImageProxy> image, Frame frame)
+VideoDecoder::emit (shared_ptr<const Film> film, shared_ptr<const ImageProxy> image, Frame decoder_frame)
 {
        if (ignore ()) {
                return;
        }
 
+       double const afr = _content->active_video_frame_rate(film);
+
+       Frame frame;
+       if (!_position) {
+               /* This is the first data we have received since initialisation or seek.  Set
+                  the position based on the frame that was given.  After this first time
+                  we just cound frames, since (as with audio) it seems that ContentTimes
+                  are unreliable from FFmpegDecoder.  They are much better than audio times
+                  but still we get the occasional one which is duplicated.  In this case
+                  ffmpeg seems to carry on regardless, processing the video frame as normal.
+                  If we drop the frame with the duplicated timestamp we obviously lose sync.
+               */
+               _position = ContentTime::from_frames (decoder_frame, afr);
+               if (_content->video->frame_type() == VIDEO_FRAME_TYPE_3D_ALTERNATE) {
+                       frame = decoder_frame / 2;
+                       _last_emitted_eyes = EYES_RIGHT;
+               } else {
+                       frame = decoder_frame;
+               }
+       } else {
+               if (_content->video->frame_type() == VIDEO_FRAME_TYPE_3D_ALTERNATE) {
+                       DCPOMATIC_ASSERT (_last_emitted_eyes);
+                       if (_last_emitted_eyes.get() == EYES_RIGHT) {
+                               frame = _position->frames_round(afr) + 1;
+                       } else {
+                               frame = _position->frames_round(afr);
+                       }
+               } else {
+                       frame = _position->frames_round(afr) + 1;
+               }
+       }
+
        switch (_content->video->frame_type ()) {
        case VIDEO_FRAME_TYPE_2D:
                Data (ContentVideo (image, frame, EYES_BOTH, PART_WHOLE));
@@ -91,9 +123,13 @@ VideoDecoder::emit (shared_ptr<const Film> film, shared_ptr<const ImageProxy> im
                break;
        }
        case VIDEO_FRAME_TYPE_3D_ALTERNATE:
-               Data (ContentVideo (image, frame / 2, (frame % 2) ? EYES_RIGHT : EYES_LEFT, PART_WHOLE));
-               frame /= 2;
+       {
+               DCPOMATIC_ASSERT (_last_emitted_eyes);
+               Eyes const eyes = _last_emitted_eyes.get() == EYES_LEFT ? EYES_RIGHT : EYES_LEFT;
+               Data (ContentVideo (image, frame, eyes, PART_WHOLE));
+               _last_emitted_eyes = eyes;
                break;
+       }
        case VIDEO_FRAME_TYPE_3D_LEFT_RIGHT:
                Data (ContentVideo (image, frame, EYES_LEFT, PART_LEFT_HALF));
                Data (ContentVideo (image, frame, EYES_RIGHT, PART_RIGHT_HALF));
@@ -112,7 +148,7 @@ VideoDecoder::emit (shared_ptr<const Film> film, shared_ptr<const ImageProxy> im
                DCPOMATIC_ASSERT (false);
        }
 
-       _position = ContentTime::from_frames (frame, _content->active_video_frame_rate(film));
+       _position = ContentTime::from_frames (frame, afr);
 }
 
 void