The rational for this is another issue that plex has exposed. When it is conducting a transcode of video to HLS for streaming, my father noticed artifacts when played on his GoogleTV (NSZ-GT1). He sent me a test file and I reproduced it on my device of the same model. It is important to note that the artifacts were not present when streaming to VLC or QuickTime Player. I copied the command-line that plex used, and conducted all of the following tests using FFmpeg git.
Transcode to HLS: artifacts on playback Transcode to TS: playback is fine Cat HLS segments into a single TS: playback is fine Segment single TS file to segments: artifacts on playback Segment single TS file to segments using Apple's HLS segmenter: playback is fine
At this point I carefully examined the differences between Apple's HLS segmenter output and FFmpeg's. Among the considerable differences, I noticed that the video PES packets always had a 0 length. So I continued:
Transcode to HLS using FFmpeg with 0 length PES packets: playback is fine. Segment single TS to segments with 0 length PES packets: playback is fine.
All failures mentioned are only on the GTV since it is the only player on which I could reproduce artifacts. I only tested the GTV, VLC, and QuickTime Player though, so my test case is limited. I do not know if other players exhibit this issue.
Since it was useful last time, I have uploaded the test file as hls_pes_packet_length.m4v along with its associated txt file which contains the transcode command-line that was used.
60fcc19b9 avformat/mpegtsenc: Changed Video PES packet length to 0.
libavformat/mpegtsenc.c | 3 +++
tests/ref/lavf/ts | 2 +-
2 files changed, 4 insertions(+), 1 deletion(-)