L'octidi 28 brumaire, an CCXXVI, Michael Roitzsch a écrit :
> Hi FFmpeg team,
> I was using af_pan to subtract one audio file from another. I first used an 
> amerge filter and then configured the pan filter with a channel formula like 
> c0=c0-c2|c1=c1-c3.
> However, this does not work as expected. In debug output, I can see that 
> channel 0 correctly uses gain coefficients 1 and -1 for c0 and c2. But 
> channel 1 incorrectly uses -1 and -1 for c1 and c3.
> I looked into the code and found that the sign handling is currently wrong. 
> When the last contribution of a formula is subtracted, the sign variable will 
> be correctly set to -1 in line 191. But when then leaving the gains loop in 
> line 189, because we reached the end of the formula for an output channel, 
> sign is not reset. We therefore re-enter the gains loop for the next output 
> channel with sign still -1. The first gain in this new formula will therefore 
> be negated.
> The attached patch fixes the problem for me.

Thanks, applied.


  Nicolas George

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