[FFmpeg-user] Intel QSV Transcoding Stops on Resolution Change

[Xiang, Haihao]

On Wo, 2024-09-04 at 17:15 +0200, Oliver Fromme wrote:
> Shane Warren wrote:
>  > The -noautoscale seems to have fixed the stop/crash on resolution
>  > changing. I can now hw decode using vaapi, then deinterlace/scale,
>  > then qsv encode. I have a capture on an input stream that does all
>  > kinds of horrible things (switches resolution and goes interlaced), I
>  > have looped that many times and the output is stable.
>  >
>  > The autoscale/noautoscale option should be in the ffmpeg html
>  > documents online somewhere, that option is very useful for anyone
>  > transcoding live streams that change resolutions.
> 
> The option is already described in the documentation.
> Quote:
> 
>    -autoscale
>       Automatically scale the video according to the resolution of
>       first frame.  Enabled by default, use -noautoscale to disable
>       it.  When autoscale is disabled, all output frames of filter
>       graph might not be in the same resolution and may be inadequate
>       for some encoder/muxer.  Therefore, it is not recommended to
>       disable it unless you really know what you are doing.  Disable
>       autoscale at your own risk.
> 
> Actually I'm surprised that -noautoscale fixes your problem.
> The default (-autoscale) should be the right one for streams that
> change resolution.  Maybe there is a peculiarity with the QSV code
> that requires -noautoscale.

This shouldn't a QSV specific case because the inserted scale filter for
autocale doesn't support hw frame. 

Thanks
Haihao