X-Git-Url: https://git.carlh.net/gitweb/?a=blobdiff_plain;f=src%2Flib%2Fvideo_decoder.cc;h=5dd078553659b21d3c09bcf8a030ea77e73ad783;hb=1f82930e73679d6aec5223caa255f564339a1a2a;hp=43b1049ccaf5f89920147f040cf5e96635f66675;hpb=39bc73fe192f932ed6695eb87b19de446e8b4f55;p=dcpomatic.git

diff --git a/src/lib/video_decoder.cc b/src/lib/video_decoder.cc
index 43b1049cc..5dd078553 100644
--- a/src/lib/video_decoder.cc
+++ b/src/lib/video_decoder.cc
@@ -35,6 +35,7 @@ VideoDecoder::VideoDecoder (shared_ptr<const VideoContent> c)
 #else
 	: _video_content (c)
 #endif
+	, _same (false)
 {
 
 }
@@ -61,8 +62,12 @@ VideoDecoder::decoded_video (VideoFrame frame)
 list<ContentVideo>
 VideoDecoder::get_video (VideoFrame frame, bool accurate)
 {
-	if (_decoded_video.empty() || (frame < _decoded_video.front().frame || frame > (_decoded_video.back().frame + 1))) {
-		/* Either we have no decoded data, or what we do have is a long way from what we want: seek */
+	/* At this stage, if we have get_video()ed before, _decoded_video will contain the last frame that this
+	   method returned (and possibly a few more).  If the requested frame is not in _decoded_video and it is not the next
+	   one after the end of _decoded_video we need to seek.
+	*/
+	   
+	if (_decoded_video.empty() || frame < _decoded_video.front().frame || frame > (_decoded_video.back().frame + 1)) {
 		seek (ContentTime::from_frames (frame, _video_content->video_frame_rate()), accurate);
 	}
 
@@ -70,7 +75,8 @@ VideoDecoder::get_video (VideoFrame frame, bool accurate)
 
 	/* Now enough pass() calls should either:
 	 *  (a) give us what we want, or
-	 *  (b) hit the end of the decoder.
+	 *  (b) give us something after what we want, indicating that we will never get what we want, or
+	 *  (c) hit the end of the decoder.
 	 */
 	if (accurate) {
 		/* We are being accurate, so we want the right frame.
@@ -105,8 +111,8 @@ VideoDecoder::get_video (VideoFrame frame, bool accurate)
 		}
 	}
 
-	/* Clean up decoded_video */
-	while (!_decoded_video.empty() && _decoded_video.front().frame < (frame - 1)) {
+	/* Clean up _decoded_video; keep the frame we are returning, but nothing before that */
+	while (!_decoded_video.empty() && _decoded_video.front().frame < dec.front().frame) {
 		_decoded_video.pop_front ();
 	}
 
@@ -118,8 +124,10 @@ VideoDecoder::get_video (VideoFrame frame, bool accurate)
 void
 VideoDecoder::video (shared_ptr<const ImageProxy> image, VideoFrame frame)
 {
-	/* We should not receive the same thing twice */
-	assert (_decoded_video.empty() || frame != _decoded_video.back().frame);
+	/* We may receive the same frame index twice for 3D, and we need to know
+	   when that happens.
+	*/
+	_same = (!_decoded_video.empty() && frame == _decoded_video.back().frame);
 
 	/* Fill in gaps */
 	/* XXX: 3D */
@@ -143,7 +151,7 @@ VideoDecoder::video (shared_ptr<const ImageProxy> image, VideoFrame frame)
 		_decoded_video.push_back (ContentVideo (image, EYES_BOTH, PART_WHOLE, frame));
 		break;
 	case VIDEO_FRAME_TYPE_3D_ALTERNATE:
-		_decoded_video.push_back (ContentVideo (image, (frame % 2) ? EYES_RIGHT : EYES_LEFT, PART_WHOLE, frame));
+		_decoded_video.push_back (ContentVideo (image, _same ? EYES_RIGHT : EYES_LEFT, PART_WHOLE, frame));
 		break;
 	case VIDEO_FRAME_TYPE_3D_LEFT_RIGHT:
 		_decoded_video.push_back (ContentVideo (image, EYES_LEFT, PART_LEFT_HALF, frame));