[FFmpeg-devel] [PATCH 1/2] lavu/hwcontext_qsv: add support for AV_PIX_FMT_VUYX
Xiang, Haihao
haihao.xiang at intel.com
Mon Sep 5 09:05:12 EEST 2022
On Sun, 2022-09-04 at 22:04 -0700, Philip Langdale wrote:
> On Mon, 5 Sep 2022 02:47:44 +0000
> "Xiang, Haihao" <haihao.xiang-at-intel.com at ffmpeg.org> wrote:
>
> > On Mon, 2022-08-29 at 14:01 +0000, Xiang, Haihao wrote:
> > > On Mon, 2022-08-29 at 08:17 -0300, James Almer wrote:
> > > > On 8/29/2022 4:27 AM, Xiang, Haihao wrote:
> > > > > From: Haihao Xiang <haihao.xiang at intel.com>
> > > > >
> > > > > AV_PIX_FMT_VUYX is used in FFmpeg for 8bit 4:4:4 content on
> > > > > Intel HW, and MFX_FOURCC_AYUV is used in the SDK
> > > >
> > > > Sounds like you want the VUYA pixfmt instead.
> > >
> > > AV_PIX_FMT_VUYX is used for 4:4:4 content in the VAAPI path,
> > > AV_PIX_FMT_VUYX is
> > > expected when creating vaapi urface. QSV is based on
> > > VAAPI under Linux, so AV_PIX_FMT_VUYX is expected too in the QSV
> > > path when creating vaapi surface.
> > >
> > > >
> > > > > ---
> > > > > libavutil/hwcontext_qsv.c | 8 ++++++++
> > > > > 1 file changed, 8 insertions(+)
> > > > >
> > > > > diff --git a/libavutil/hwcontext_qsv.c
> > > > > b/libavutil/hwcontext_qsv.c index 510f422562..a3350eae0f 100644
> > > > > --- a/libavutil/hwcontext_qsv.c
> > > > > +++ b/libavutil/hwcontext_qsv.c
> > > > > @@ -119,6 +119,8 @@ static const struct {
> > > > > MFX_FOURCC_YUY2 },
> > > > > { AV_PIX_FMT_Y210,
> > > > > MFX_FOURCC_Y210 },
> > > > > + { AV_PIX_FMT_VUYX,
> > > > > + MFX_FOURCC_AYUV },
> > > > > #endif
> > > > > };
> > > > >
> > > > > @@ -1502,6 +1504,12 @@ static int map_frame_to_surface(const
> > > > > AVFrame *frame,
> > > > > mfxFrameSurface1 *surface)
> > > > > surface->Data.U16 = (mfxU16 *)frame->data[0] + 1;
> > > > > surface->Data.V16 = (mfxU16 *)frame->data[0] + 3;
> > > > > break;
> > > > > + case AV_PIX_FMT_VUYX:
> > > > > + surface->Data.V = frame->data[0];
> > > > > + surface->Data.U = frame->data[0] + 1;
> > > > > + surface->Data.Y = frame->data[0] + 2;
> > > > > + surface->Data.A = frame->data[0] + 3;
> > > >
> > > > This will go wrong with VUYX. You need to use AV_PIX_FMT_VUYA.
> > >
> > > frame->data[0] + 3 is valid even if alpha channel is ignored in
> > > VUYX. Intel HW doesn't use the data in alpha channel actually, but
> > > the SDK uses Microsoft pixel
> > > format AYUV which is the alpha version, here set a valid address to
> > > alpha channel when mapping a VUYX AVFrame to a AYUV mfx surface.
> > >
> >
> > Is there more comment about this patch ?
>
> Wouldn't it be more correct to fill the Data.A with 0xFF rather than
> using the undefined value from the frame? I assume that the encoder
> actually drops the value completely so it ultimately doesn't matter,
> but it makes it clear that there is no alpha and if the encoder was to
> start preserving it, it would preserve the desired value.
Yes, you're right that the encoder drops the value. I'll add some comment in the
patch.
Thanks
Haihao
More information about the ffmpeg-devel
mailing list