[FFmpeg-devel] [PATCH] mpeg4videodec: silence "Invalid and inefficient vfw-avi packed B frames detected" warning

Reimar Döffinger Reimar.Doeffinger at gmx.de
Thu Aug 29 21:55:17 CEST 2013

On Thu, Aug 29, 2013 at 07:48:32PM +0000, Paul B Mahol wrote:
> On 8/29/13, wm4 <nfxjfg at googlemail.com> wrote:
> > On Thu, 29 Aug 2013 21:31:54 +0200
> > Nicolas George <nicolas.george at normalesup.org> wrote:
> >
> >> Le duodi 12 fructidor, an CCXXI, wm4 a ecrit :
> >> > Seeking (resetting the decoder) causes the warning to be printed again.
> >> > Disabling warnings is not an option, because warnings are supposed to
> >> > signal that something might be wrong.
> >>
> >> So it is printed once after each seek. How is that a problem?
> >>
> >> It informs about a problem that can have practical consequences (try
> >> playing
> >> this kind of files with a limited CPU) and can be fixed (although not with
> >> ffmpeg for now). That is exactly what a warning is made for. Simply
> >> removing
> >> it would be idiotic.
> >
> > The warning is completely meaningless and confusing.
> Perhaps warning can be printed only if error recognition is set to
> some reasonable value?

One of the reasons for the warning is to make people stop using the
tools that create these broken files.
Ideally also to fix them.
However I think it is badly worded for that purpose.
In the link I gave I suggested at least pointing to tools
to fix it.
What would be a reasonable way?
'Video uses a non-standard and wasteful way to store B-frames ("packed
B-frames"). Consider using a tool like VirtualDub or avidemux to fix

Is it really a problem if it's printed always when seeking?
I don't see the big deal with warning messages for files that definitely
are badly done.


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