[FFmpeg-devel] [PATCH] PES Packet Length to 0 for video in TS
michaelni at gmx.at
Tue Apr 22 16:35:34 CEST 2014
On Sat, Apr 12, 2014 at 01:51:54PM +0100, Kieran Kunhya wrote:
> 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.
i dont know that either ...
but h264 has to be included as thats what the issue was about
Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
I have never wished to cater to the crowd; for what I know they do not
approve, and what they approve I do not know. -- Epicurus
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