Add replay gain generation

[filipfigzalski]

Hi,
First of all great project, it works really well for my usecase.

I was searching for a way to make lidarr automatically generate replay gain values for files. I've found this issue on lidarr's repo. Seems that the best way would be to create a plugin. So I was wondering whether this functionality could be implemented in Tubifarry. It already does things like codec conversion so it wouldn't be that far off the project scope (please correct me if I'm wrong). It could potentially be achieved by passing the imported directories to an external command-line tool like rsgain.

I would gladly help with implementing this, however I have no experience with c#, neither lidarr's plugin system.

[TypNull]

I've thought about this, but I've identified two problems I'd appreciate your help with.
First, when Lidarr re tags metadata, does it delete the gain tag? If so, that's a limitation I can't work around.

Second, I need the standalone portable version to work across Windows, Linux (both standard and Alpine), and macOS. Alpine is particularly challenging, which is why the Python branch remains separate. Does rsgain run as a portable application on Alpine?

[filipfigzalski]

From my quick tests it seems that it doesn't delete replay gain tags and this pull request confirms it.

Regarding your second point: I just spun up an alpine container to test the official standalone, but I cannot seem to run the binary. I get not found error. However, rsgain is available on the alpine repository via apk add rsgain.

[TypNull]

This is difficult because without root access I can’t install a package internally, and 80% of users won’t be running as root, nor should they. It’s the same issue I run into with Python execution.

[filipfigzalski]

I see the issue. I think there are two solutions:

1. Make the user responsible for providing rsgain.
2. It is possible to point apk to some custom path, which can be written to without root permissions. Then we could point PATH and LD_LIBRARY_PATH to this custom location.

I was able to install and run rsgain this way.

Here are the steps I've took:

docker run -it --rm -u 1000:1000 alpine:latest sh -c "cd /tmp && sh"
export MY_ROOT=/tmp/packs
mkdir -p $MY_ROOT
apk add rsgain --root $MY_ROOT --initdb --keys-dir /etc/apk/keys --repositories-file /etc/apk/repositories --no-cache --usermode
export PATH=$MY_ROOT/usr/bin:$MY_ROOT/bin:$PATH
export LD_LIBRARY_PATH=$MY_ROOT/usr/lib:$MY_ROOT/lib:$LD_LIBRARY_PATH
rsgain # should work now

[TypNull]

I can give it a try when I have time. If you’d like, you can open a feature request, and I’ll review it when my schedule allows.