please use playbin2, playbin is deprecated in 0.10.
It seems your sink has ANY caps in its template, this is likely not
true. You should specify the formats that it supports to make sure that
converters can act if needed.
Also, it seems that you have posted some very incomplete element code.
Either you didn't implement or you omitted too much it is hard to help
From the code I can see, you are pushing the h264 buffers on your
decoder as you receive, meaning that you aren't really decoding them and
also they are carrying on the same caps of the input. This means that
your h264 decoder takes h264 on input and produces h264 on its output
where downstream elements are likely expecting some sort of raw video.
Re: video decoder and video sink plugins not negotiating using playbin
Thanks a lot Thiago for the reply. You pointed it out correctly that, I did not change the output buffer caps. Actually, I have to use a hardware h264 decoder core to decode the input stream. I would be reading the output 'raw' data to a new gst buffer and push it to the src pad. Attached code was the initial gstreamer wrapper for the same before implementing the hardware stuff.