[FFmpeg-devel] Questions about Video Memory in qsv decoders

[Michael Niedermayer]

On Sat, Jul 23, 2016 at 11:19:59PM +0300, Ivan Uskov wrote:
> Hello 张玉晓,
> 
> Friday, July 22, 2016, 4:10:36 AM, you wrote:
> 
> 张> I have a question when learning ffmpeg qsv decoder and Intel media sdk.
> 
> 张> The intel media sdk suggest to use Video Memory while doing Hardware
> 张> decoding, use System Memory while doing Software decoding.
> 
> 张> FFmpeg only used System Memory to decode with qsv (Intel msdk) in file
> 张> libavcodec/qsvdec.c. Is there any problem when use Video Memory? 
> 
> As qsv modules maintainer I can confirm, yes, there are problems.
> 
> First (objective) problem that in common case there are 3 qsv components
> should be linked by a pipeline through GPU memory: 
> *qsv video decoder
> *qsv vpp filter
> *qsv video encoder
> But current ffmpeg architecture have restrictions to share one common qsv
> session between libavcodec and libavfilter.
> 
> Second  (subjective) problem that nobody in ffmpeg community is interested to
> advance  QSV  codecs. Most of  patches at this year provided by me or by my
> colleagues (including tries to solve issue with GPU memory) were rejected or
> ignored silently. Moreover, if you will try to clone a latest ffmpeg you found qsv
> decoder broken, it crashes at any try of use. The patch to fix it was posted
> by me at April 25 but was ignored.

btw, this patch lacks a review too:
"0618  6:33 zeranoe at gmail.c (2.8K)   └─>[FFmpeg-devel] [PATCH] avcodec/qsv: remove MFX_EXTBUFF_CODING_OPTION3"

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

I have often repented speaking, but never of holding my tongue.
-- Xenocrates
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