feat(windows, linux) : Added setBalance method

[novikov-studio]

Description

Added method:

/// -1 - The left channel is at full volume; the right channel is silent.
///  1 - The right channel is at full volume; the left channel is silent.
///  0 - Both channels are at the same volume.
AudioPlayer.setBalance(double value)

Platforms

Windows - yes
Linux - yes

Related Issues

closes #58

[Gustl22]

Nice 👍 I'd prefer to add the integration tests first in #1238 and then can add this feature to the example / tests, too.

[Gustl22]

@novikov-studio Would you mind adding buttons to the example and adding tests, now that #1238 is merged. Need to rebase or merge main branch first.
I thought of adding 5 Buttons to Controls Tab with values: [-1, -0.5, 0, 0.5, 1] like done here.

[novikov-studio]

@Gustl22, done.

[Gustl22]

Thanks for your work.

You also have to overwrite setBalance in web implementation, otherwise the test will fail.

It would also be good to overwrite it in the other implementations (darwin, android) and throw an explicit unimplemented error or add a logger error, although it's not mandatory, but would give a better error message, what is not implemented yet.

Best regards

[novikov-studio]

@Gustl22, I make setBalance to work for web (inspired by this).
But it only works if I set player.crossOrigin = "anonymous" and that makes me doubt,
Need some help with that.

[Gustl22]

Hi @novikov-studio,
this wasn't my intention, that you need to implement the balance for web platform, you could have just thrown an UnimplementedError. But nice that you tried it.

It also works for me, but dart:web_audio isn't exposed to pub. So even if it works, we shouldn't use it as it's not officially supported. Also the flutter linter would not allow this. See flutter/flutter#49849
I saw @luanpotter already had a discussion on that: dart-lang/pub-dev#3277

You should try to work via JS interface: https://pub.dev/packages/js , but I never used it, so I cannot give you a promise that it will work.
But if it's too much effort right now, we can do this in a separate MR.

Regarding the crossOrigin flag, I also have no clue. It may solves itself when using JS interface 🤷

[Gustl22]

@novikov-studio somehow, the linux implementation works on my Ubuntu machine. But on my WSL2 via windows it give the error, which is also in the CI workflow:

Error: 1; message=Internal data stream error.
flutter: Unexpected platform error: Error: 1; message=Internal data stream error.

Are we missing a package? I wonder if ALSA plays a role here.

[novikov-studio]

setBalance uses GStreamer's audiopanorama plugin, which is in "GStreamer Good Plug-ins" package.
So, maybe gstreamer1-plugins-good is missing.

[Gustl22]

sorry, that's not the problem. It's also installed via the workflow. I'll try to figure it out tomorrow, if you can't reproduce it right now :)

[Gustl22]

FYI: @novikov-studio I also reworked the web implementation in this branch, but the cors flag is still needed.

[novikov-studio]

Sorry, I never used WSL2, so I can't reproduce.

[Gustl22]

I now used autoaudiosink following this tutorial: https://gstreamer.freedesktop.org/documentation/tutorials/playback/custom-playbin-sinks.html?gi-language=c
I think ALSA is not available on WSL2 or Ubuntu-Servers on GH-Actions