[FFmpeg-devel] [PATCHv6 4/4] libavcodec: v4l2: add support for v4l2 mem2mem codecs

Jorge Ramirez jorge.ramirez-ortiz at linaro.org
Mon Aug 28 15:16:28 EEST 2017

On 08/28/2017 12:47 PM, wm4 wrote:
>> I guess that instead of polling for the AVBufferRef to be unreferenced,
>> I can associate a sync (ie a sempahore) to each buffer, take it on
>> release and post the semaphore on the AVBufferRefs being unreferenced.
>> that is actually pretty clean in terms of cpu usage.
> That would just freeze an API user calling avcodec_close(), when it
> keeps around decoded AVFrames for later use.

yes I understand, but it does avoid using the CPU to poll for the buffer 
release (an incremental improvement)

but yes I think that the message is that even though this proposal might 
suffice for simple video players (my tests) is not good enough for other 
users requiring the decoded frame for post processing.

is this a blocker to upstream or could I continue working with it 
flagging the encoder/decoder as EXPERIMENTAL? the current situation at 
least keeps video players happy.

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