Hi, gstreamer-devel:     Normally, it should be no problem if you just change your gstreamer from 0.10.9 to 0.10.21. "max-size-buffers" should also work.     So, I think you should provide more debug infos and do some tests(E.g: put a probe before your video/audio sinks and see whether there is buffers flow into them; Turn on debug infos on basesink and your sink elements and see what the sinks exactly do during preroll) yourself and figure out why the preroll can't be performed. Eric Zhang <div class="gmail_quote">2008/12/28 Sameer Naik <<a href="mailto:sameer.subscriptions@damagehead.com">sameer.subscriptions@damagehead.com</a>> <blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"> Hi, I have written a  gstreamer plugin that does video decoding on specialized hardware, and also written a videosink plugin that opens the framebuffer device,etc . For optimizing the entire pipeline the videosink plugin has the _pad_alloc functionality, that directly makes available the framebuffer memory to the decoder plugin, so that the output images can directly be written to the video memory. I would also mention, that the videosink can make available 3 such buffers (triple buffering) to the decoder, so effectively the decoder should not request for more than three buffers at the same time, in which case if it does the _pad_alloc function will not return any buffer. Now, if i construct my pipeline as such gst-launch filesrc location=file.mpeg ! demultiplexer name=demux ! videodecoder ! queue ! videosink  demux. ! audiodecoder ! audioconvert ! queue ! audiosink what happens is, due to the queue element (after the videodecoder), the part of the bin goes into its own thread. as a result, the videodecoder ends up making a lot more buffer requests to the videosink, than the videosink can really allocate. Due to this, in gstreamer version 0.10.9 i would add the queue before the videodecoder. like so gst-launch filesrc location=file.mpeg ! demultiplexer name=demux ! queue ! videodecoder ! videosink  demux. ! audiodecoder ! audioconvert ! queue ! audiosink and everything works fine. But the current version 0.10.21 does not allow me to do this, as in the pipeline does not PREROLL. I would like to know, whether it is possible to control how the queue functions so that it does not store more than 3 buffers. i tried specifying max-size-buffers=3 on the queue, but it did not help. I would also be interested in knowing any other ways this can be taken care of. Reagrds ~Sameer ------------------------------------------------------------------------------ _______________________________________________ gstreamer-devel mailing list <a href="mailto:gstreamer-devel@lists.sourceforge.net">gstreamer-devel@lists.sourceforge.net</a> <a href="https://lists.sourceforge.net/lists/listinfo/gstreamer-devel" target="_blank">https://lists.sourceforge.net/lists/listinfo/gstreamer-devel</a> </blockquote></div>