[FFmpeg-devel] [PATCH] PES Packet Length to 0 for video in TS

Kieran Kunhya kierank at obe.tv
Sat Apr 12 14:51:54 CEST 2014

On 12 April 2014 05:43, Graham Booker <gbooker at cod3r.com> wrote:
> I propose that PES packet lengths in TS should be set to 0 for video
> streams.  Patch attached as reference.
> 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.
> Thank you for taking the time to look into this.

Should be OK. I'm not sure if this should be restricted to MPEG-2 and
MPEG-4 though.

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