[FFmpeg-devel] ffmpeg logging on stderr

Michael Niedermayer michaelni
Thu Mar 10 15:36:14 CET 2011

On Thu, Mar 10, 2011 at 02:59:08PM +0100, Stefano Sabatini wrote:
> On date Thursday 2011-03-10 01:15:40 +0000, M?ns Rullg?rd encoded:
> > Stefano Sabatini <stefano.sabatini-lala at poste.it> writes:
> [...]
> > > We could print it just before the transcode() function (or the ff*
> > > corresponding function) is called, but since the parsing is done
> > > before you could have the app printing an error and exit, in this case
> > > you don't have the version message in the error log (which is annoying
> > > in case you are reading a bug-report).
> > >
> > > Possible solutions:
> > > * implement pre-parsing of the commandline (overkill?)
> > > * remove the version header, and ask the users to always report ff*
> > >   -version when reporting bugs / asking for help (and you can bet that
> > >   they mostly won't)
> > 
> > We should at least make it go away with -v 0 (or maybe -1).  The amount
> > of console spam spewed forth by ffmpeg these days isn't even funny.  All
> > the useless metadata dumps didn't make it better.  In 99% of cases I
> > don't care whatsoever about what muxer some file claims to have been
> > created with etc.  If I need to know that specific bit of information, I
> > know how to find it.
> Yes I agree. I have some ideas, for example:
> always use av_log for logging in ffmpeg / other tools, advantages:
> fancy coloring, the users don't have to care about the distinction
> between application and library logging (why should they?), and we
> could drop -v.

For us this has its appeal but it makes the ff* tools more differnt from
other applications using lav*. Others wont and often cannot switch all their
printing code to av_log()
it makes our tools less suitable as example applications
iam undecided ...

> Currently we're mixing av_log with fprintf(stderr) with
> no criteria.

The critera ia av_log() in the libs, and *printf() in the applications

> Then we could preparse the -loglevel option *or* a -q option (easily
> done with few lines of code, shared between all ff* tools), which
> enables skipping to print the header.

what is the problem with
-q 2>/dev/null

or what problem are you trying to solve?

[... ]
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

it is not once nor twice but times without number that the same ideas make
their appearance in the world. -- Aristotle
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