[FFmpeg-devel] [PATCH] hwcontext_d3d11va: implement av_hwdevice_get_hwframe_constraints()

wm4 nfxjfg at googlemail.com
Tue Jan 16 19:05:08 EET 2018


On Tue, 16 Jan 2018 17:47:14 +0100
Steve Lhomme <robux4 at ycbcr.xyz> wrote:

> Le 16/01/2018 à 17:42, wm4 a écrit :
> > On Tue, 16 Jan 2018 14:08:37 +0100
> > wm4 <nfxjfg at googlemail.com> wrote:
> >  
> >> D3D11 has rather fine grained per texture format capabilities for
> >> different uses that can be queried at runtime. Since we don't know at
> >> the time av_hwdevice_get_hwframe_constraints() is called what the user
> >> wants to do with this, we simply return all formats that have the most
> >> basic support.
> >> ---
> >>   libavutil/hwcontext_d3d11va.c | 33 +++++++++++++++++++++++++++++++++
> >>   1 file changed, 33 insertions(+)
> >>
> >> diff --git a/libavutil/hwcontext_d3d11va.c b/libavutil/hwcontext_d3d11va.c
> >> index 2f97156a54..960883c9d8 100644
> >> --- a/libavutil/hwcontext_d3d11va.c
> >> +++ b/libavutil/hwcontext_d3d11va.c
> >> @@ -120,6 +120,38 @@ static void d3d11va_frames_uninit(AVHWFramesContext *ctx)
> >>       s->staging_texture = NULL;
> >>   }
> >>   
> >> +static int d3d11va_frames_get_constraints(AVHWDeviceContext *ctx,
> >> +                                          const void *hwconfig,
> >> +                                          AVHWFramesConstraints *constraints)
> >> +{
> >> +    AVD3D11VADeviceContext *device_hwctx = ctx->hwctx;
> >> +    int nb_sw_formats = 0;
> >> +    HRESULT hr;
> >> +    int i;
> >> +
> >> +    constraints->valid_sw_formats = av_malloc_array(FF_ARRAY_ELEMS(supported_formats) + 1,
> >> +                                                    sizeof(*constraints->valid_sw_formats));
> >> +    if (!constraints->valid_sw_formats)
> >> +        return AVERROR(ENOMEM);
> >> +
> >> +    for (i = 0; i < FF_ARRAY_ELEMS(supported_formats); i++) {
> >> +        UINT format_support = 0;
> >> +        hr = ID3D11Device_CheckFormatSupport(device_hwctx->device, supported_formats[i].d3d_format, &format_support);
> >> +        if (SUCCEEDED(hr) && (format_support & D3D11_FORMAT_SUPPORT_TEXTURE2D))  
> 
> If you want to check the format can be used by the decoder, you should 
> at least check for
> D3D11_FORMAT_SUPPORT_DECODER_OUTPUT

Yeah, but it's not necessarily used for decoding. There are other valid
uses of D3D surfaces, e.g. video processor input (and it's realistic
that someone would add support for that to libavfilter).

Mark Thompson suggested on IRC that hwconfig could be used to pass
special requirements (such as whether the surface is to be used for
decoding), so if we ever need this later, it's extensible.


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