This week as well I didn’t write too much code, but did some investigation nonetheless. Monday was a bank holiday, that was pretty cool.
I landed a few things that are not interesting, and then got pinged by Steven Yi on the amazing Web Audio API slack, that said that Firefox doesn’t decode AAC properly. It doesn’t trim the encoder delay (often 1024 or 2112 sample-frames), and also doesn’t trim the padding (whatever number of frame is needed to align the last packet to 1024 frames), so I’m fixing that. I fixed the same bug, but for mp3 not too long ago, although I still need to do a follow-up because I found a couple files where my approach falls apart (in a weird edge case where you have the padding spanning two packets — that makes no sense to me).
I’m really rusty when it comes to the playback code of Firefox, but it’s getting better.
I had been using the venerable
tool, but I just got pointed to
https://gpac.github.io/mp4box.js/test/filereader.html, which is essentially the
same, but on the Web, so I can run it on my Linux box. That said,
runs very well using Wine and the Windows-version of the .Net runtime (an
installer), when you install it in the Wine environment.
That’s where most of the time in the week went, mostly reviewing the image decoder proposal for Web Codecs, and a bunch of other PRs on audio/video. We are continuing to chat with people that are the target users for this API, and finding new stuff.
Nothing on the Web Audio API, as expected. We’re working on V2 issues though.
I did a comparison study on all the different ways to resample and chop a classic break (of course I started with the amen) in Ableton Live. There is quite a few ways to do it, but only a small numbers of those technique allow getting it to sound like it would on, say, an Akai S950. I have a MUM M8 in my modular system, that is based on the S950 filter, so I should be able to get pretty convincing result at the end, with a workflow a bit more modern than working on one of those hardware samplers.
I then proceeded to do a ridiculous demo tune where lots of clichés of UK hardcore/happy hardcore are represented:
- an intentionally bad piano. I don’t have a Korg M1 or an emulation, which is the nec-plus-ultra for the genre, I took something random in Ableton Live
- an (hopefully) well chopped amen
- an Apache break
- a 909 overdriven with a (fake) Mackie desk
- a 808 sub bass sample processed through a low quality sampler also hitting a (fake) Mackie desk
- an emulated 303 into a fake tube screamer
- a landlord stab
- a sample of Neneh Cherry saying profanities
- beautiful reverbs provided by Valhalla DSP of course, their VintageVerb and the new free one, SuperMassive