[Gstreamer-openmax] AV Sync with Gst-OpenMax pluggin

[Felipe Contreras]

Hi Nitin,

On Mon, Feb 8, 2010 at 11:25 AM, Nitin PAI <nitinmpai at gmail.com> wrote:
> I am working on adding gstreamer support for our proprietary openmax
> multimedia stack.  So the best choice is to use gst-openmax pluggin.
> I am facing problems with Audio Video Synchronization.
>
> Basically,
> 1) How is startup AV sync handled in gst-openmax pluggin?  There is a deep
> pipeline in our audio stack. Just EmptyBufferDone call from audio sink
> doesnt imply that the audio is played. This is handled via FirstAudioFrame
> played event from the openmax core.
> 2) How is AV sync done. I mean basically the decision to do video frame
> drops or video frame hold?
>
> I will really appreciate some writeup on this.

Well, first of all, tunneling is not implemented yet in gst-openmax,
there are some proposed patches but apparently some big changes are
needed since GStreamer's base classes don't seem to consider these
cases.

Then there's the problem of A/V sync. This has been discussed in the
past and the consensus is that the best way to implement this would be
to map OpenMAX IL clock to GStreamer's clock.

I don't have plans to implement this, so somebody else would need to do that.

-- 
Felipe Contreras