[FFmpeg-devel] [FFmpeg-cvslog] lavc/qsvenc: add VDENC support for H264

[Li, Zhong]

> From: ffmpeg-devel [mailto:ffmpeg-devel-bounces at ffmpeg.org] On Behalf
> Of Carl Eugen Hoyos
> Sent: Friday, January 11, 2019 1:06 AM
> To: ffmpeg-devel at ffmpeg.org
> Subject: Re: [FFmpeg-devel] [FFmpeg-cvslog] lavc/qsvenc: add VDENC
> support for H264
> 
> 2019-01-10 14:51 GMT+01:00, Linjie Fu <git at videolan.org>:
> 
> > +#if QSV_HAVE_VDENC
> > +    { "low_power", "enable low power mode(experimental: many
> > +limitations by
> > mfx version, BRC modes, etc.)", OFFSET(qsv.low_power),
> > AV_OPT_TYPE_BOOL, {
> > .i64 =  0 }, 0, 1, VE},
> > +#endif
> 
> This seems wrong to me: The visibility of an option should probably not
> depend on configuration details (the effect can of course depend on many
> details).
> 
> Carl Eugen

That's is just a remind that this feature has some limitations. The configures are just to make driver to support this feature.
In ffmpeg level, the only thing we should do IMHO is to query MSDK/Driver capability and report an error message if not supported.
And it was done: https://github.com/FFmpeg/FFmpeg/blob/395e8a53fa0266f26581f3e9752b0dbc93998a90/libavcodec/qsvenc.c#L376