On 9/12/18, Michael Koch <[email protected]> wrote: > Am 12.09.2018 um 09:55 schrieb Paul B Mahol: >> Hi, >> >> On 9/12/18, Michael Koch <[email protected]> wrote: >>> Is it possible to multiply audio samples from two sources? >>> I'd like to downconvert the 15kHz to 25kHz range to the 0 to 10kHz >>> range. First apply a strong 15kHz highpass filter, then multiply the >>> signal with a 15kHz sine wave (which produces sum and difference >>> signals), then apply a 10kHz lowpass filter. >> There is no yet amultiply audio filter, but I could write it. >> >> Am I correct that for it you need two audio streams as input and one >> audio stream as output? > > yes, two inputs and one output. I think it would be best if it works > independant of bit depth. First normalize the input signals to -1...+1 > range, then multiply them so that the result is also in the -1...+1 > range, then normalize back to 16bit or 24bit range.
It will internally work with floating-point numbers only (32bits or 64bits). Normalization is done with other filters. Meanwhile you can use sox multiply effect. Note that sox internally operates with 32bit integers. _______________________________________________ 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".
