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

[Li, Zhong]

> > Is it a possible way to show "not supported" info and set the option
> > to default off instead of  just hiding the option?
> >
> > Like:
> > #if QSV_HAVE_VDENC
> >     { "low_power", "enable low power mode (experimental, many
> > limitations by mfx version, HW platform, BRC modes, etc.)",
> > OFFSET(qsv.low_power), AV_OPT_TYPE_BOOL, { .i64 =  0 }, 0, 1, VE}, #
> > else
> >     { "low_power", "not supported", OFFSET(qsv.low_power),
> > AV_OPT_TYPE_BOOL, { .i64 =  0 }, 0, 0, VE}, #endif
> 
> This is also an option but I wonder if a failure message wouldn't help users
> even more.

It give a remind to user to prevent to set an useless option, instead of setting it and expect it will take effect.
Do you have any other suggestion? How about giving an error message after user set it? 
Just like:
#if QSV_HAVE_VDENC
    q->param.mfx.LowPower           = q->low_power ? MFX_CODINGOPTION_ON : MFX_CODINGOPTION_OFF;
#endif
    av_log(avctx, AV_LOG_ERROR, "low_power mode is not support");
#endif 

(IMHO, I prefer to Linjie's solution instead of this one).