[FFmpeg-devel] [RFC] AVFilter Parser

Aurelien Jacobs aurel
Sat Mar 22 03:14:39 CET 2008

Michael Niedermayer wrote:

> On Fri, Mar 21, 2008 at 10:02:35PM +0100, Michael Niedermayer wrote:
> > Hi
> > 
> > Well, after various flames, discussions, some implementation and so
> > on. Heres yet another proposal, this time mostly properly defined,
> > i hope this will avoid flames and misuderstandings.
> > This one is quite similar to the previous proposals, the main
> > difference besides a clear definition of things is the
> > feedback/feedforward syntax. The new syntax avoids the often cited
> > problem with string insertion of predefined filter graphs and name
> > colissions.
> Some examples for filters from a filter lib:
> my_filter0='picInPic;nop , picInPic'
> that filter would place stream 1 and 2 as subpics in stream 0

Indeed, but it took me a long time to understand it.
I know it's clearly defined in your syntax definition. But when
reading this example, I intuitively though that ; has a higher
priority than ,. I'm not sure why I had this impression. Maybe
that's only because that's the way it was used in the original
Anyway, just replacing the ; with a * (with the exact same
definition) would have made it much more intuitive to me,
because * generally has a high priority. (But maybe that's
just me ?)


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