<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 TRANSITIONAL//EN"> <HTML> <HEAD> <META HTTP-EQUIV="Content-Type" CONTENT="text/html; CHARSET=UTF-8"> <META NAME="GENERATOR" CONTENT="GtkHTML/4.2.2"> </HEAD> <BODY> Le jeudi 17 novembre 2011 à 22:42 -0800, chandu a écrit : <BLOCKQUOTE TYPE=CITE> <PRE> 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. </PRE> </BLOCKQUOTE> 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).<BR> <BR> cheers,<BR> Nicolas </BODY> </HTML>