[FFmpeg-devel] [PATCH] avdevice/xcbgrab: Improve non-shm performance

[Kusanagi Kouichi]

On 2019-12-04 22:32:52 +0100, Marton Balint wrote:
> 
> 
> On Wed, 4 Dec 2019, Kusanagi Kouichi wrote:
> 
> > On 2019-12-03 21:25:37 +0100, Marton Balint wrote:
> > > 
> > > 
> > > On Tue, 3 Dec 2019, Kusanagi Kouichi wrote:
> > > 
> > > > On 2019-11-19 22:59:56 +0900, Kusanagi Kouichi wrote:
> > > > > Use AVBufferPool.
> > > 
> > > You don't need a buffer pool for the non-shm case, you should wrap the XCB
> > > data in a buffer ref instead. I will reply with a patch that shows how it is
> > > done, please check if it works correctly, as I am not 100% sure how xcb data
> > > structures should be allocated/freed.
> > > 
> > 
> > Is it safe to omit AV_INPUT_BUFFER_PADDING_SIZE bytes padding? My first
> > version is identical to yours. Valgrind reported no error. But I'm not sure.
> 
> Strictly speaking it is against the API, but the performance gains IMHO are
> too big to respect the API requirement blindly. Also I see little chance
> that it will cause issues, because typically avcodec/rawdec.c will simply
> reassign the buffer ref to an AVFrame and keep the data untouched. And
> AVFrame data does not have this requirement. If something breaks, we can
> always reconsider this or find another solution.
> 
> Regards,
> Marton

OK, Then can you commit your patch?