Composers Desktop Project Forum

I don't know if this is your problem, but often times when I get that error it's because the output file already exists and CDP won't overwrite it.

I'm trying to use CDP to create single cycle waveforms to use in some of my synths. I've been digging around the docs but haven't had any real luck... here's what I'm trying to do:

1. Extract one or more pseudo-wavecycles from a long audio file
2. Modify it so that it's 600 samples long (or some other arbitrary sample length)

I've found sfedit zcut which lets me extract parts of samples at zero crossings, but they're not pseudo-wavecycles. I can't find a way to restrict the number of zero crossings it finds. Is there a way to do that with CDP?

And then once I have a single cycle waveform, how can I change it so it's a certain number of samples?

Okay thanks. And I wonder about cases where there is no input file, e.g. synth wave? Will there be (in this upcoming update) a way to configure CDP to use 24-bit as the default for those things? Or perhaps convert to 24-bit as part of housekeep respec?

And if you mix a 16-bit file with a 24-bit file, will it produce a 24-bit file?

Thanks for that explanation. I probably should have run some tests in other audio processing software before posting here! 

I don't know much about DSP. And I've heard that 32-bit has "virtually unlimited headroom" and you can test it out by increasing the gain a bunch in a daw, and bringing it back down, and everything sounds fine. I just assumed that meant the operations were "perfect" in increasing and lowering the gain would produce an identical file.

There's definitely no audible difference. And now I have a better understanding of what happens â€" thanks!

Here's something interesting... if I use 32-bit with CDP_NOCLIP_FLOATS=1, I can increase the gain above 0 dBFS and then back down, with no clipping, as expected. BUT the resulting file is no longer identical to the original file! You can see it for yourself in this experiment. If you uncomment lines 57-62 you'll see that the comparison fails. And indeed, running "sndinfo diff" on the original and processed files shows that they differ starting from the very beginning. Finally, if I invert one and mix it with the other, the gain is reduced but they don't null.

So something seems to be off. I'm staying in floating point from start to finish... and while the processed file sounds identical to the original file, they are not bit-for-bit identical.

Any ideas as to what's going on? Is it CDP's fault, or mine?

All of the files that CDP produces are 16-bit. I've seen that there's a -f flag and associated env var somewhere that will make output files be 32-bit floating point... but I don't need that

I'd like CDP to output 24-bit files instead of 16-bit. Is there some setting to make that happen?

I found out about CDP just recently and have been having fun experimenting with it. I'm working on tiny little projects to learn the functionality and develop a method of working with it. I've put my work on GitHub for anyone who may be interested in following along. It's all pretty trivial stuff so far, but if CDP feels overwhelming then trivial might be just the ticket!