On Fri, Aug 09, 2024 at 09:43:53AM +0200, Lluís Batlle i Rossell wrote:
> On Fri, Aug 09, 2024 at 11:49:54AM +0800, Zhao Zhili wrote:
> > > vaapi drivers often lack proper image converesions and not all
> > > situations allow vagetimage or vaputimage with the image formats
> > > reported by the api. nv12 seems allowed in all circumstances.
> > > 
> > > with this change now one can use the hwaccel directly without
> > > explicit conversions to nv12 for frame downloading to work.
> > > 
> > > gstreamer adopted a similar approach:
> > > https://bugzilla.gnome.org/show_bug.cgi?id=752958
> > 
> > Isn’t it break all pixel formats with bit depth > 8?
> > I think we already have hwcontext API to select sw_format, this isn’t a bug
> > inside ffmpeg.
> 
> Correct... I didn't think of the need beyond NV12.
> 
> What if I redo the patch so I keep all formats, but I simply move NV12 to
> the first place? That will make ffmpeg pick NV12 as default if NONE
> specified.

I attach a different patch, so NV12 is only picked in case the dst format
is NONE.