[FFmpeg-devel] [PATCH] vp9: add hwaccel hooks

Hendrik Leppkes h.leppkes at gmail.com
Thu Dec 3 17:29:12 CET 2015

On Thu, Dec 3, 2015 at 5:21 PM, Ronald S. Bultje <rsbultje at gmail.com> wrote:
> Hi,
> On Thu, Dec 3, 2015 at 4:55 AM, Hendrik Leppkes <h.leppkes at gmail.com> wrote:
>> +    if (s->pix_fmt == AV_PIX_FMT_YUV420P) {
>> +        *fmtp++ = AV_PIX_FMT_DXVA2_VLD;
>> +#endif
>> +        *fmtp++ = AV_PIX_FMT_D3D11VA_VLD;
>> +#endif
>> +    }
> So ... this suggests that hwaccels will ever only support 420, 8bpp. That
> may currently be true, but is that likely to hold forever? What happens if
> we just do this regardless of pixfmt and let the hwaccel figure out if the
> hw supports 420 or something else?

At the very least the DXVA2 hwaccel spec is limited to profile 0, so
maybe it should even check the profile on top of this.
In general, there is some disagreement if other chroma formats should
use other hwaccel pixfmts, as the calling code can otherwise get
confused, as it may need special handling to handle other chroma
formats. However, since no hwaccel supports anything else yet (except
hevc, which can do 420 10-bit, but I didn't push that to ffmpeg yet),
it was not a real problem yet.

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