We're one step closer to bringing back the Flipnotes from Flipnote Hatena and Flipnote Gallery: World. Right now the hard part is figuring out the sound format. We had a breakthrough today: originally we thought it was VOX ADPCM, nibbles reversed, at 16kHZ, but there was always a lot of loud background noise. As it turns out, it may actually be bitpacked, where the samples are of a variable bitrate to save space. If this is the case, then we should be able to work it how those bitlengths are stored and decode the audio cleanly!
James, id:rakujira, is heading the work to reverse-engineer the format. (as in, he's doing the real work!)
You can find our documentation of the format here:
As well as a parser here (Go follow his GitHub!):