[FFmpeg-devel] [PATCH 02/12] doc: Explain the various logevel settings

Stefano Sabatini stefasab at gmail.com
Sat Mar 30 23:11:17 CET 2013


On date Saturday 2013-03-30 17:31:58 -0400, Derek Buitenhuis encoded:
> On 2013-03-30 5:05 PM, Stefano Sabatini wrote:
> >>  @item panic
> >> +Deprecated. Does nothing.
> > 
> > Tool docs are not the place where to deprecate symbols.
> > 
> > libavutil/log.h
> > /**
> >  * Something went really wrong and we will crash now.
> >  */
> > #define AV_LOG_FATAL
> > 
> > Translated to English this could sound like:
> > 
> > @item panic
> > Only show critical errors leading to the crash of the process.
> 
> Problem is, this isn't even true. It's literally used nowhere in Libav, and ONLY
> in vf_sub, as a proxy for libass's warning levels. This is just a lie.

The fact that we have no such log messages doesn't mean we might not
have them in the future. Also it might be used in wrapped libraries
(PANIC level was borrowed from syslog error levels, and thus it's a
sort of informal standard).

> 
> >>  @item fatal
> >> +Only show fatal errors. These are errors after which the process absolutely
> >> +cannot continue after.
> > 
> > Technically not correct, since this will also show panic errors (and
> > in general log messages with a lower level).
> 
> Panic errors don't actually exist in the codebase.
> 

> > Possibly more correct, but longer:
> > 
> > Only show fatal errors, in addition to the ones shown with
> > @samp{panic}. These are errors after which the process absolutely
> > cannot continue after.
> 
> See above.

Feel free to change this to "Only show fatal errors", and drop the
mention to panic.

> >>  @item error
> >> +Show all errors. These errors will cause problems, but the process can
> >> +recover and continue.
> > 
> > Ditto.
> 
> See above.

Still technically wrong, since this will show also fatal errors, which
are not recoverable.

[...]
-- 
FFmpeg = Fascinating and Foolish Multimedia Portentous Enhanced Gadget


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