Mailing List Archive

Option "Use FFmpeg's original MPEG-TS demuxer"
Hi,

I'd like to consult the collective memory about the option "Use FFmpeg's
original MPEG-TS demuxer".
Me and PaulH have been looking into playback issues with recordings from
the Finnish channel YLE. The playback issues disappear when this option is
selected. See mailing list
https://forum.mythtv.org/viewtopic.php?p=21615#p21615 for details.

However, this option is only available when a debug build is made and the
option is accompanied by a threatening help text:
"Experimental: Enable this setting to use FFmpeg's native demuxer. Things
will be broken."

Does anybody know where this all comes from?
Is there really a reason to hide this option?
I'd like to make the option always available as it appears solve the YLE
problem.

Thanks,
Klaas.
Re: Option "Use FFmpeg's original MPEG-TS demuxer" [ In reply to ]
On 31/03/2021 21:44, Klaas de Waal wrote:
> Hi,
>
> I'd like to consult the collective memory about the option "Use FFmpeg's
> original MPEG-TS demuxer".
> Me and PaulH have been looking into playback issues with recordings from
> the Finnish channel YLE. The playback issues disappear when this option
> is selected. See mailing list
> https://forum.mythtv.org/viewtopic.php?p=21615#p21615
> <https://forum.mythtv.org/viewtopic.php?p=21615#p21615> for details.
>
> However, this option is only available when a debug build is made and
> the option is accompanied by a threatening help text:
> "Experimental: Enable this setting to use FFmpeg's native demuxer.
> Things will be broken."
>
> Does anybody know where this all comes from?
> Is there really a reason to hide this option?
> I'd like to make the option always available as it appears solve the YLE
> problem.
>
> Thanks,
> Klaas.

I can't comment on this proposal, and I haven't examined the current
clip; but when this YLE problem came up last year it looked as if the
cause was a rapid change in the stream structure at the start of the
recording. I suspect the 'things that work' are just workarounds for
this.

https://code.mythtv.org/trac/ticket/13557#comment:33

HTH

John P


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Re: Option "Use FFmpeg's original MPEG-TS demuxer" [ In reply to ]
Hi.

I added that option many moons ago.
It was mostly designed at the time to check if a mpeg-ts file was
broken; not something that would typically be a problem with OTA
recordings but when dealing with HLS streaming could be quite common.

The mythtv mpeg-ts demuxer is very old and has received very little
updates over the years.

Things that will be broken using the ffmpeg's mpegts demuxer are
mostly subtitles and how to choose different audio tracks.
It doesn't support the callbacks that myth required when the
resolution or the content changes.

So it's fine to play a simple file, anymore than that and it's not gonna work.


On Thu, 1 Apr 2021 at 07:45, Klaas de Waal <klaas.de.waal@gmail.com> wrote:
>
> Hi,
>
> I'd like to consult the collective memory about the option "Use FFmpeg's original MPEG-TS demuxer".
> Me and PaulH have been looking into playback issues with recordings from the Finnish channel YLE. The playback issues disappear when this option is selected. See mailing list https://forum.mythtv.org/viewtopic.php?p=21615#p21615 for details.
>
> However, this option is only available when a debug build is made and the option is accompanied by a threatening help text:
> "Experimental: Enable this setting to use FFmpeg's native demuxer. Things will be broken."
>
> Does anybody know where this all comes from?
> Is there really a reason to hide this option?
> I'd like to make the option always available as it appears solve the YLE problem.
>
> Thanks,
> Klaas.
>
>
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> mythtv-dev mailing list
> mythtv-dev@mythtv.org
> http://lists.mythtv.org/mailman/listinfo/mythtv-dev
> http://wiki.mythtv.org/Mailing_List_etiquette
> MythTV Forums: https://forum.mythtv.org
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