I think it is better to write your own videorate plugin or modify videorate plugin to support DMAI buffer than modify gstbuffer.

2010/3/16 Arnout Vandecappelle <arnout@mind.be>
 Hoi all,

 I'm currently hacking with the DMAI plugins that use the DSP on the TI OMAP
for video encoding and other transformations.  These plugins require
specially allocated DMA buffers to be able to communicate with the DSP.  A
custom GstTIDmaiBufferTranport sub-class of GstBuffer is used for that.
When the encoder element receives a buffer, it checks whether it is a
GstTIDmaiBufferTransport; if not, it memcpy's the data in a DMA buffer.

 Since the memcpy's completely kill performance in my application, I make
sure that GstTIDmaiBufferTransport buffers are allocated in the beginning of
the pipeline.  However, when I insert a videorate element in the pipeline,
it creates subbuffers of these.  These are no longer recognized as
GstTIDmaiBufferTransport objects, and therefore the physical address of the
DMA buffer is not accessible.  Hence, there are memcpy's again.

 To work around this, I've added a function to GstBuffer that checks if it
is a subbuffer and if so returns the parent buffer.  Does this sound like a
good solution?  If so, I'll put it in bugzilla.

 Regards,
 Arnout
--
Arnout Vandecappelle                               arnout at mind be
Senior Embedded Software Architect                 +32-16-286540
Essensium/Mind                                     http://www.mind.be
G.Geenslaan 9, 3001 Leuven, Belgium                BE 872 984 063 RPR Leuven
LinkedIn profile: http://www.linkedin.com/in/arnoutvandecappelle
GPG fingerprint:  31BB CF53 8660 6F88 345D  54CC A836 5879 20D7 CF43

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