demux, player: fix playback of sparse video streams (w/ still images)

Fixes several issues playing back mpegts with video streams marked
as having "still images". For example, see this video which has
frames only every 6s: https://s3.amazonaws.com/tmm1/music-choice.ts

Changes include:
- start playback right away, without waiting for first video frame
- do not consider the sparse video stream in demuxer underrun detection
- do not require multiple video frames for the VO
- use audio as the master stream for demuxer metadata events
- use audio stream for playback time

Signed-off-by: Aman Gupta <aman@tmm1.net>

1 files changed, 2 insertions, 0 deletions

diff --git a/player/core.h b/player/core.h
index bc6cf28ff0..71c39dcaa5 100644
--- a/player/core.h
+++ b/player/core.h
@@ -180,6 +180,8 @@ struct vo_chain {
     // - video consists of a single picture, which should be shown only once
     // - do not sync audio to video in any way
     bool is_coverart;
+    // - video consists of sparse still images
+    bool is_sparse;
 };
 
 // Like vo_chain, for audio.