[FFmpeg-devel] [PATCH V2 3/3] avfilter/vf_dnn_processing.c: add frame size change support for planar yuv format

[Guo, Yejun]

> -----Original Message-----
> From: ffmpeg-devel [mailto:ffmpeg-devel-bounces at ffmpeg.org] On Behalf Of
> mypopy at gmail.com
> Sent: Friday, March 06, 2020 10:49 AM
> To: FFmpeg development discussions and patches <ffmpeg-devel at ffmpeg.org>
> Subject: Re: [FFmpeg-devel] [PATCH V2 3/3] avfilter/vf_dnn_processing.c: add
> frame size change support for planar yuv format
> 
> On Tue, Feb 25, 2020 at 5:24 PM Guo, Yejun <yejun.guo at intel.com> wrote:
> >
> > The Y channel is handled by dnn, and also resized by dnn. The UV channels
> > are resized with swscale.
> For me, this is a little weird to resize Y with dnn backend but resize
> UV channel with FFmpeg swscale, is it used the same scale algorithm ?
> 

thanks for the review. The Y channel and UV channel use different algorithms,
the algorithm for Y channel is trained with dnn, while UV channel ignored in dnn model.

It would be nice if all channels are handled by the dnn model. But, for the popular
dnn models I know, they just handle the Y channel, that's the reason that we
have to ask swscale's help to handle UV channels. And the same idea is also
used in vf_sr.c, we can first handle this case.

I can add such support once I see there are some popular good models
which handle YUV channels together.

thanks
yejun