Replace AtomicParsley with lofty-rs

[miraclx]

Related: #82

In certain cases, AtomicParsley falls short. Like embedding long rDNSatom keys. wez/atomicparsley#44

In the spirit of #305, we could replace it with a wasm bundled version of https://github.com/Serial-ATA/lofty-rs

Which should allow us to support more formats beyond AAC and even export the original audio with only metadata embedded. #168

And be free of native dependencies.

[orsett0]

Couldn't we just use ffmpeg? This way i think we could even embed the metadata during the encoding process

[miraclx]

Even ffmpeg uses AtomicParsley to embed metadata.

Looks like I misread, I thought you had said youtube-dl.

ffmpeg doesn't support metadata embedding into AAC containers which the mp4 format (.m4a) uses, so this doesn't work.

[orsett0]

That's not entirely true. It supports all the tags currently used by freyr-js, for the exception of apID, purd, ©enc, rDNSatom and rtng, unless you specify a flag in ffmpeg which however messes with the other metadata. (*)

Also, metadata written with ffmpeg can't be read by AtomicParsley, and this makes me think that they are not readable by iTunes too. They can however be read by other players.

I don't know if you consider these metadata to be important, but if they aren't, I could make a PR in a few days implementing the use of ffmpeg to embed metadata. Otherwise I can't offer a solution, as I'm not experienced in rust nor wasm.

(*) the flag is -movflags use_metadata_tags. I don't know exactly how it works, given that I can't find proper documentation, but it renders metadata such as the track number not readable by vlc and others.

[miraclx]

Also, metadata written with ffmpeg can't be read by AtomicParsley, and this makes me think that they are not readable by iTunes too.

That is a point of concern for this project.

I don't have much time these days, but this is worth investigating. I will if I ever find the time. Or if you do, and can submit a PR, I'd be happy to test and review it. Reusing the embedded ffmpeg wasm binary for this would save on third-party requirements and make freyr a "download only" solution.

The help would be very much appreciated.

Otherwise, I'm pretty happy with the state of things as it is.

[orsett0]

Hi, I was working on using ffmpeg to add metadata, but then I noticed that some tags were not recognized correctly by other music players, so I abandoned the idea.

I wanted to develop a WASM version of lofty-rs, but due to university I didn't have much time. I think I can start working on it in a couple of days and I'll be happy to submit a PR once I get things to work.

[miraclx]

That would be amazing, feel free to reach out if you need any help. Thank you!