maks
commented
11 months ago So I tried looking this up and it seems there is no agreed upon standard for how many samples should be in a single cycle waveform file, but I did find this:
There is a lot of variation in the numbers of samples that are used to represent a single cycle waveform. In Max (and MaxForLive), the ~cycle object originally defaulted to using 512 samples of a single cycle of a cosine wave. But it wasn't fixed - you could replace the default waveform by using any other set of 512 samples, or you could change the number of samples: more recent versions of Max use 16,000 64-bit samples. A lot of the single cycle waveforms that you find on the InterWeb are 337 samples long, whilst others have 256, 1024, 2048 or 4096.
So given a 44 byte header for RIFF format, in the case of AKWF he used 600 samples each, so 600 * 2 + 44 = 1244 bytes so I'm not sure where the other 100 bytes comes from but I think we could just have some preset file sizes (for specific number of samples) that we could look for to determine if a file is likely a single cycle waveform?
democloid
It would be nice to be able to audition single cycle files in the Import Dialog. Current behaviour is just to play samples as a single shot, streamed from the sdcard.
Instead what should happen is that single cycle files should be detected and then played back in a loop using existing code.
We need some sort of heuristic to detect single cycle files, looking at the "AKWF" collection I have they are all exactly 1344 bytes so that seems like a good starting point.
For playback, it might be a bit tight ram wise, but since all the AKWFs are only 1344 bytes, we could just load them into a ram buffer and play from there just as the lgpt code did for all samples prior to the changes that load samples now into flash on the pico.