caps negotiation

Nicolas Dufresne nicolas.dufresne at
Fri Nov 18 11:01:34 PST 2011

Le jeudi 17 novembre 2011 à 22:42 -0800, chandu a écrit :

> Hi,
> I just started reading about gstreamer. i understood the concept of caps
> negotiation. But could not find the difference between upstream and down
> stream caps negotiation. both looks same for me, negotiating the source pad
> capabilities. Can any one tell me the difference.

Downstream caps negotiation is the normal way. An exemple is a decoder.
While decoding it figures out what format it will output and informs
downstream of that format (using pads). Upstream negotiation is a rare
case, the one I know about is the video sink. They know the window size,
and try upstream negotiation to optimize the size of the buffer received
(using buffer allocation in .10, this is removed in .11).

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <>

More information about the gstreamer-devel mailing list