I am running Audacity 3.74 under Windows 10, trying to synchronize 1 1/2 hour continuously recorded digital audio with 1 1/2 hour video continuously recorded on a different device. I provide an exact selection length or number of samples and the speed and tempo effect returns a slightly different length. The comments below are from January 2017. The same or a similar problem still exists or has returned. Response was by Steve the Fiddle.
Steve the Fiddle wrote:
As I wrote in December 2015, I fixed the Change Speed effect, but as
anticipated, the fix was too late for Audacity 2.1.2, so it will be in
Audacity 2.1.3 which is due for release soon.
Steve
On 3 January 2017 at 12:52, John Allen <…> wrote:
An additional thought:
I don’t think that it is a coincidence that my clip is 276.6 million samples
long and that the speed change is in an increment of 520 + 2245 = 2765 (give
or take) samples.Calculation of the ratio of new length to original length is apparently
rounded to one part in 10^5 before conversion from decimal to binary. My
hunch is that the calculation is being passed through the program module
which displays percent change. In any case, this is a serious design flaw.Calculation in 32-bit integer math would be much, much better (15 steps per
sample in my 276 million sample recording); 64-bit, perfect for nearly all
practical purposes.The resampler achieves 64-bit, maybe floating-point
precision in locating samples. There must be a way…