[FFmpeg-devel] [PATCH v7 1/8] libavcodec/qsv: enabling d3d11va support, added mfxhdlpair

[Max Dmitrichenko]

On Thu, Jul 15, 2021 at 5:49 AM Soft Works <softworkz at hotmail.com> wrote:

>
>
> > -----Original Message-----
> > From: ffmpeg-devel <ffmpeg-devel-bounces at ffmpeg.org> On Behalf Of
> > James Almer
> > Sent: Thursday, 15 July 2021 05:21
> > To: ffmpeg-devel at ffmpeg.org
> > Subject: Re: [FFmpeg-devel] [PATCH v7 1/8] libavcodec/qsv: enabling
> > d3d11va support, added mfxhdlpair
> >
> > On 7/15/2021 12:10 AM, Soft Works wrote:
> > >
> > >
> > >> -----Original Message-----
> > >> From: ffmpeg-devel <ffmpeg-devel-bounces at ffmpeg.org> On Behalf Of
> > >> Xiang, Haihao
> > >> Sent: Thursday, 15 July 2021 04:35
> > >> To: ffmpeg-devel at ffmpeg.org
> > >> Subject: Re: [FFmpeg-devel] [PATCH v7 1/8] libavcodec/qsv: enabling
> > >> d3d11va support, added mfxhdlpair
> > >>
> > >> On Tue, 2021-07-13 at 11:53 -0300, James Almer wrote:
> > >>> On 11/14/2020 1:49 PM, Max Dmitrichenko wrote:
> > >>>> On Tue, Nov 3, 2020 at 7:47 PM Artem Galin <artem.galin at gmail.com>
> > >> wrote:
> > >>>>
> > >>>>> Adding DX11 relevant device type checks and adjusting callbacks
> > >>>>> with proper MediaSDK pair type support.
> > >>>>>
> > >>>>> Extending structure for proper MediaSDK pair type support.
> > >>>>>
> > >>>>> Signed-off-by: Artem Galin <artem.galin at intel.com> .....
> > >>>>
> > >>>>
> > >>>> Patchset obviously closes the gap of DirectX 11 support and already
> > >>>> checked with several apps that use FFMPEG.
> > >>>>
> > >>>> Any particular review comments should be yet expected?
> > >>>>
> > >>>> Changes seem to be straight forward and incorporate prev. comments.
> > >>>>
> > >>>> thank in advance
> > >>>>
> > >>>> regards
> > >>>> Max
> > >>>
> > >>> There are some issues pointed out by Soft Works related to switching
> > >>> the default to DX11 breaking existing command lines with DX9, plus
> > >>> an OpenCL<->QSV interop regression this would introduce that
> > >>> according to him should be easy to fix.
> > >>>
> > >>> If those are addressed, the set should be good.
> > >>
> > >> If we may apply http://ffmpeg.org/pipermail/ffmpeg-devel/2021-
> > >> June/281778.html
> > >> (qsvdec: add support for HW_DEVICE_CTX method) first, we should be
> > >> able to use the common device stuff to initialize d3d11va device for
> > >> QSV and needn't use child_device_type to specify child device.
> > >
> > > There's no doubt that the new method will be better, but the point is
> not
> > to break existing command lines. From my experience, ffmpeg usually
> avoids
> > to break established command line patterns, which is a good thing imo.
> > >
> > > Anything more official than my perception? Please feel free to chime
> > > in... ;-)
> >
> > That patch appears to attempt to maintain support for existing command
> > lines for a deprecation period, something we've done before with other
> > hwaccels like cuvid, so if it's really better, it's fine and acceptable.
> ^
>
> Hi James,
>
> "That patch" that preserves compatibility doesn't exist yet. We need to
> make sure that command lines using the '--child_device' parameter will
> continue to work, while Haihao's patch will be the "future way":
>
> > -init_hw_device d3d11va=d3d11va:xxx -init_hw_device qsv at d3d11va
>
> The new behaviour that is introduced by this patch is that an initialized
> hw device can now be applied to qsv decoders (currently only to filter
> graphs and qsv encoders).
>
> Additionally, the default should remain to be D3D9 (if none of the above
> is specified) as laid out earlier - again for maintaining compatibility but
> also for better robustness and performance.
>
>
Upon introduction of DX11/D3D11VA support, it makes sense to make it
default as well,
this would help for upcoming implementations and general usages in the long
run,
including new usages, as headless platforms support,
which is an obvious D3D9 gap, as an example.

Compatibility is still preserved and available with D3D9 path, there is no
functional change.
If D3D9 is critical for further usage - it has to be requested explicitly.

regards
Max