[FFmpeg-devel] [PATCH 2/2] lavfi: reimplement MPlayer's af_pan filter for libavfilter.

[Nicolas George]

Le primidi 21 brumaire, an CCXX, Stefano Sabatini a écrit :
> hard on my eyes, maybe easier:
> pan=stereo:c0=0.4:0:0:0.4:0.2:0, c1=0:0.2:0.3:0.3:0.1:0.1
> 
> or even:
> pan=stereo:FL=0.4:0:0:0.4:0.2:0,FR=0:0.2:0.3:0.3:0.1:0.1
> 
> anyway I think the spec for each channel specification should go
> separated from the others.

This is not the same syntax as MPlayer's pan filter. But since FFmpeg and
MPlayer are two distinct tools, I do not think we should feel obligated to
keep the syntax.

If we go that way, then we can be more ambitious, for example:

pan=stereo:FL=0.6*FL+0.4*RL:FR=0.6*FR+0.4*RR

or even, with automatic removal of inexistent channels and normalization:

pan=stereo:FL=FL+0.6*RL/:FR=FR+0.6*RR/

(equivalent to FL=0.625*FL+0.375*RL or to just FL=FL, depending on whether
RL exists or not; I could not come up with a better syntax than the trailing
'/', but if someone has a better idea, I would like to see it)

This above is quite easy to write. We could go for even more ambitious, with
Turing-complete decision features, but I fear we would not finish anytime
soon.

Regards,

-- 
  Nicolas George
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 198 bytes
Desc: Digital signature
URL: <http://ffmpeg.org/pipermail/ffmpeg-devel/attachments/20111111/056b247a/attachment.asc>