PTS/DTS clearing in gcc sink pad

[Jun Xiao]

Thanks Mathieu and Thibault!

>> This is because the `rtpgccbwe` is doing the pacing[0], implying buffer
>> timestamps are meanigless after that point,
Make sense.  Just to confirm,
mutbuf.set_pts(None)/mutbuf.set_dts(None) won't impact timestamps in RTP,
right?

>>  in `webrtcbin` we
>> synchronize the streams upstream of that element we can thus remove the
>> timestamps so that downstream elements will not do any clock
>> synchronization anymore.
How does `webrtcbin` synchronize the streams upstream? Could you please
share some code pointers?

Thanks,
Jun

On Fri, Jan 13, 2023 at 10:24 PM Thibault Saunier via gstreamer-devel <
gstreamer-devel at lists.freedesktop.org> wrote:

> Hi,
>
> This is because the `rtpgccbwe` is doing the pacing[0], implying buffer
> timestamps are meanigless after that point, in `webrtcbin` we
> synchronize the streams upstream of that element we can thus remove the
> timestamps so that downstream elements will not do any clock
> synchronization anymore.
>
> - Thibault
>
> [0]
> https://datatracker.ietf.org/doc/html/draft-ietf-rmcat-gcc-02#section-4
>
> On Fri, 2023-01-13 at 22:12 +0800, Jun Xiao via gstreamer-devel wrote:
> > Hi Mathieu,
> >
> > In gcc/imp.rs, I found the sink pad is doing following:
> >   mutbuf.set_pts(None);
> >   mutbuf.set_dts(None);
> >
> > I am curious what the purpose of this clearing is, and will DTS/PTS
> > be re-provisioned by any subsequent element in a pipeline? Could you
> > help to elaborate this.
> >
> > Thanks,
> > Jun
>
>
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