+ DCPOMATIC_ASSERT (false);
+ }
+
+ /* Now VideoDecoder is required never to have gaps in the frames that it presents
+ via get_video(). Hence we need to fill in any gap between the last thing in _decoded_video
+ and the things we are about to push.
+ */
+
+ optional<Frame> from;
+ optional<Frame> to;
+
+ if (_decoded_video.empty() && _last_seek_time && _last_seek_accurate) {
+ from = _last_seek_time->frames_round (_video_content->video_frame_rate ());
+ to = to_push.front().frame;
+ } else if (!_decoded_video.empty ()) {
+ from = _decoded_video.back().frame + 1;
+ to = to_push.front().frame;
+ }
+
+ /* If we've pre-rolled on a seek we may now receive out-of-order frames
+ (frames before the last seek time) which we can just ignore.
+ */
+
+ if (from && to && from.get() > to.get()) {
+ return;
+ }
+
+ if (from) {
+ switch (_video_content->video_frame_type ()) {
+ case VIDEO_FRAME_TYPE_2D:
+ fill_one_eye (from.get(), to.get (), EYES_BOTH);
+ break;
+ case VIDEO_FRAME_TYPE_3D_LEFT_RIGHT:
+ case VIDEO_FRAME_TYPE_3D_TOP_BOTTOM:
+ case VIDEO_FRAME_TYPE_3D_ALTERNATE:
+ fill_both_eyes (from.get(), to.get(), to_push.front().eyes);
+ break;
+ case VIDEO_FRAME_TYPE_3D_LEFT:
+ fill_one_eye (from.get(), to.get (), EYES_LEFT);
+ break;
+ case VIDEO_FRAME_TYPE_3D_RIGHT:
+ fill_one_eye (from.get(), to.get (), EYES_RIGHT);
+ break;
+ }
+ }
+
+ copy (to_push.begin(), to_push.end(), back_inserter (_decoded_video));
+
+ /* We can't let this build up too much or we will run out of memory. There is a
+ `best' value for the allowed size of _decoded_video which balances memory use
+ with decoding efficiency (lack of seeks). Throwing away video frames here
+ is not a problem for correctness, so do it.
+ */
+ while (_decoded_video.size() > 96) {
+ _decoded_video.pop_back ();