[FFmpeg-devel] [PATCH] lavfi/volume: add dynamic expression evaluation

[Stefano Sabatini]

On date Tuesday 2013-03-05 16:08:54 +0100, Nicolas George encoded:
> Le quartidi 14 ventôse, an CCXXI, Stefano Sabatini a écrit :
> > That's a solution (or add a filter variant). The other solution would
> > be to make the filter behaves in a different way if the expression is
> > constant (CONST OP CONST is detected as constant), which would need
> > some hack to the eval code (of course this can't detect things like
> > EXPR-EXPR).
> 
> Detecting what variables / functions are used in the expression is not
> impossible at all, and it would allow to know whether the expression is
> constant or not even in complex cases.
> 
> > Please tell what you prefer (and feel free to pick the patch and
> > improve it yourself if you're in hurry).
> 
> Could you make a quick benchmark, using a small frame size (asetnsamples=16
> for example): that would greatly help knowing whether it is worth optimizing
> that or not.

I'm trying to implement av_expr_is_const() (and trying to clean up
eval code a bit at the same time).
-- 
FFmpeg = Frightening Formidable Meaningless Power Erudite Gymnast