[FFmpeg-devel] [PATCH] libavfilter/vf_overlay_cuda: Pass the main frame to the output if secondary frame is not available. now filter fails if secondary frame is not available due to e.g secondary source delay.

[Alexander Strasser]

On 2020-08-21 20:46 +1000, Alex Pokotilo wrote:
> On Fri, Aug 21, 2020 at 7:54 PM Nicolas George <george at nsup.org> wrote:
> >
> > Alex Pokotilo (12020-08-21):
> > > From b3739e33fa04a9292dc6584bd2f31460aa53d478 Mon Sep 17 00:00:00 2001
> > > From: Alex Pokotilo <support at wmspanel.com>
> > > Date: Fri, 21 Aug 2020 09:14:37 +0000
> > > Subject: [PATCH] libavfilter/vf_overlay_cuda: Pass the main frame to the output if secondary frame is not
> > >  available. now filter fails if secondary frame is not available due to e.g secondary source delay.
> >
> > Your Git commit message is badly formatted. The format is:
> >
> >         context: short summary on one line
> >
> >         After an empty line, details if necessary, on several lines and
> >         wrapped at a reasonable line length.
> >
>
> I'm sorry. I'm a newbie. Am I right I just need to commit in following format:
>
> first line: short description......
> LF
> more details here

Yes, that should do the trick.

Please don't forget to mention the "Why" part in the commit message
body (the "more details here" part), if you re-do the patch.

At the moment it would probably best to first wait for feed back on
your explanation below.


  Alexander

> Should I send a new patch as a separate email or reply to this one ?
> Sorry again.
> > The fix may be correct, but your analysis of the problem does not prove
> > it. Unless there is a serious bug in framesync, it will not call
> > overlay_cuda_blend() without a secondary frame "due to e.g secondary
> > source delay.", it will only do so if the stream has not yet begun or
> > has ended.
> >
> > Please give more details on the exact circumstances you observe the
> > issue.
>
> I create a filter graph with vf_cuda_overlay in my application. I
> start sending frames into a "main" stream link using
> av_buffersrc_write_frame.
> I start sending frames into a "secondary" stream too almost
> immediately. I have one output sink in my filter graph.
> After each write I call av_buffersink_get_frame and get AVERROR_BUG
> from vf_overlay_cuda for some time initially but after several frames
> it starts returning mixed frame.
> I've checked vf_blend and other framesync filters. They do the same as
> I did in the fix.
>
> Maybe the problem In my application I cannot guarantee that both
> streams have the same timeline.
> Could you please point me to the place where framesync checks second
> stream availability before it calls it's filter(overlay_cuda_blend in
> my case).
> This topic is very complex to me now so any help from your side can
> really help me.