[gst-devel] totem and osssink? (long)

[Ronald Bultje]

Hi Martin,

On Thu, 11 Mar 2004, Martin Soto wrote:
> On Wed, 2004-03-10 at 23:57, Ronald S. Bultje wrote:
> > Would you mind copying this to gstreamer/docs/pwg/advanced-clock.xml so
> > other people can enjoy this story, too?
> Yeah, I'll do it as soon as I have CVS access (it's already requested).

Great, thanks!

> > It only
> > requires that demuxers send out the same event (refcounted, of course)
> > to all their sink pads. I think all demuxers already do this.
>
> Hmm, no, it's just the opposite, I guess. When implementing dvddemux, I
> noticed that mpegdemux actually creates a new discont event for every
> pad. I wondered if that was sort of a bug in mpegdemux and checked
> around only to find that other demuxers do the same (admittedly I didn't
> check all of them). I thought it was necessary for some obscure reason
> and proceeded to implement dvddemux the same way. Is there actually a
> reason for doing that? Would it be ok to start changing demuxers to just
> refcount and forward disconts?

Imo, yes. But I'd tend to say that we won't include it in 0.8.0 (I'm
careful right now. ;) ). 0.8.1 or 0.9.x sounds fine, though. If demuxers
do this, it's (imo) a bug.

> As far as I can see, these are all backwards compatible changes. In
> order for this new infrastructure to work in general, however, we need
> two things:
>
> - Elements forwarding discontinuities must just refcount discont events
> properly and forward them. Elements creating new discont events should
> create one event and send it properly refcounted to all output pads.
>
> - Sink elements must handle disconts somewhat differently:
>
>   case GST_EVENT_DISCONTINUOUS:
>     {
>       GstClockTime time;
>
>       if (gst_event_discont_get_value (event, GST_FORMAT_TIME, &time)) {
>         gst_element_set_time_serial (GST_ELEMENT (sink), time,
>             gst_event_discont_get_serial (event));
>       }
>     }

Actually, you need to add this code to the default dispatcher, that's
where the clocking code is called, too. No need for implementing this in
each element specifically.

Ronald