AAC + MPEG/AAC decoder

[probablykasper]

I made the crate redlux which decodes AAC, as well as AAC from MPEG-4 containers. It uses fdk-aac bindings to decode AAC and rust-mp4 to read the MPEG-4 containers.

If it's something that could potentially be used by rodio, feel free to. It already implements the Source trait.

It does have some potential caveats though, and to decode MPEG-4 files it needs to get the size of the file.

[est31]

Oh nice that's pretty cool! Generally, why not? I have some concerns with the fdk-aac bindings link. The -sys crate mentions the MIT license while vendoring the fdk-aac library which apparently has a custom (but open source, at least copyright wise) license.

I'm not sure about the patent situation though. It seems you'll need a license to distribute AAC decoders? If it's added to rodio it can't be turned on by default.

[probablykasper]

@est31 Yeah I had only briefly looked at the fdk-aac license.

I'm not really sure when you need a license. Many device manufacturers seem to be licensing AAC already, so does that mean you're good to go for playback on those devices since fdk-aac itself is open source?

via-corp.com's AAC FAQ says this:

Who must sign a license?

An AAC patent license is needed by manufacturers or developers of end-user encoder and/or decoder products.

Apparently the patents for LC-AAC expired over a year ago, but haven't found a good source to verify that.

[Shnatsel]

https://github.com/pdeljanov/Symphonia implements a pure-Rust LC-AAC decoder.

[aschey]

I have a branch with a Symphonia implementation working with basic functionality along with a few other changes such as seek support, although it's quite hacky and has some major caveats. See this comment for more details.