caps negotiation

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caps negotiation

chandu
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.

Thanks in advance.
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Re: caps negotiation

Nicolas Dufresne
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).

cheers,
Nicolas
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