[FFmpeg-devel] [PATCH] avcodec/dxva2_av1: use correct grain parameters with update_grain = 0

[Guangxin Xu]

On Thu, Nov 26, 2020 at 9:05 PM James Almer <jamrial at gmail.com> wrote:

> On 11/26/2020 2:34 AM, Guangxin Xu wrote:
> > spec did not forbid this.
> > Here is da1vd code:
> > https://code.videolan.org/videolan/dav1d/-/blob/master/src/obu.c#L1057
> > If  update_grain  == 0, it will copy film grain data from the reference
> > frame to the current frame.
> > Maybe we can do the same thing on CBS, Other acceleration like vaapi,
> > will get benefit from this.
>
> Yes, I sent a patchset to properly copy film grain params from reference
> frames yesterday that should cover all possible scenarios.
>
Great!👍

>
> Regarding Vaapi, its film grain implementation is incomplete, on top of
> also being affected by this issue. It doesn't look like it's filling all
> the VAFilmGrainStructAV1 fields it should.
>
The hw and driver are supported. Maybe Fei can give more details about
ffmpeg vaapi implementations
thanks


>
> >
> >
> > On Thu, Nov 26, 2020 at 3:05 AM James Almer <jamrial at gmail.com> wrote:
> >
> >> On 11/24/2020 5:59 AM, Guangxin Xu wrote:
> >>> Hi   Hendrik,
> >>> two related questions:
> >>> 1. Seems it's a generic code. Could we handle this in the av1dec.c?
> >>> 2. For the current code, what's happened if frame A ref to B, B ref to
> C.
> >>> and both A, B has update_grain == 0.
> >>
> >> Is that considered a valid bitstream? If so, then value inferring should
> >> be done in either CBS (like it's done for segmentation and loop filter),
> >> or in av1dec.c. Otherwise all the fields will be zero, same as is the
> >> case right now.
> >>
> >>> thanks
> >>>
> >>>
> >>> On Tue, Nov 24, 2020 at 4:42 AM James Almer <jamrial at gmail.com> wrote:
> >>>
> >>>> On 11/23/2020 8:38 AM, Hendrik Leppkes wrote:
> >>>>> When update_grain is zero, the parameters should be taken from a
> >>>>> reference frame instead.
> >>>>> ---
> >>>>>     libavcodec/dxva2_av1.c | 59
> >> +++++++++++++++++++++---------------------
> >>>>>     1 file changed, 30 insertions(+), 29 deletions(-)
> >>>>
> >>>> LGTM
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