On 12/20/16, Adam Puckett <[email protected]> wrote: > On 12/20/16, Muhammad Faiz <[email protected]> wrote: >> On 12/20/16, Adam Puckett <[email protected]> wrote: >>> On 12/19/16, Nicolas George <[email protected]> wrote: >>>> Oh, good catch. I should have remembered this task needed a primitive >>>> function, not just a multiplication. >>>> >>>> Regards, >>>> >>>> -- >>>> Nicolas George >>>> >>> What do I need to do to make the formula right? >> >> Just do the reverse. >> Given freq(t) = 262 * 2^(t/10) >> w(t) = 2*PI * 262 * 2^(t/10) >> ph(t) = integral of w(t) dt >> = 2*PI * 262 * 10/log(2) * 2^(t/10) + arbitrary constant >> >> Thx. >> _______________________________________________ >> ffmpeg-user mailing list >> [email protected] >> http://ffmpeg.org/mailman/listinfo/ffmpeg-user >> >> To unsubscribe, visit link above, or email >> [email protected] with subject "unsubscribe". > Thanks, that worked! But the question is: why? I don't quite > understand why I had to put in the log(2) expression. > > On a related note, I've looked at a formula that does linear > interpolation (one of the example scripts for Praat > (http://praat.org/)), and there is a division by 2 in the script; is > this for a similar reason? (For arbitrary targeted frequencies, I'm > assuming I would have to use a log(highestfreq/lowestfreq) in place of > the log(2)?) > > Thanks
It is calculus 2^(t/10) = exp(t/10 * log(2)) and integral exp(a * t) * dt = 1/a * exp(a * t) + arbitrary constant thx _______________________________________________ ffmpeg-user mailing list [email protected] http://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email [email protected] with subject "unsubscribe".
