Support for multi-channel recording

[Lovinity]

I noticed my stereo (2-channel) mediaStream was only getting its first/left channel saved into the MP3s. I also noticed in the audio process that mp3mediarecorder is only getting data from the first (left) channel.

I would like to know if/suggest mp3mediarecorder support multiple channel recordings in the future, especially since some may use this to record stereo audio (such as radio programming) for archive purposes.

Thank you!

[elsmr]

Hey, thanks for the suggestion.

I did some digging and I think it should be possible to combine all channels in the AudioBuffer before sending it to the encoder. I'll try to implement something soon when I find some time 😄

EDIT: I'm talking about combining the audio from all channels into mono audio, recording as true stereo (or more channels) will require changes in https://github.com/Kagami/vmsg

[EricTetz]

I think it should be possible to combine all channels in the AudioBuffer before sending it to the encoder

That's something the user of the library can trivially do himself at the stream level.

It was heartbreaking to do the work of integrating this into my app today (lots of UI work) only to discover it only records mono. That's worthless for music. You should mention this limitation in the readme. Calling it a ponyfill and mirroring the MediaRecorder API suggests that it has at least the same capabilities, but mono-only is a show-stopping restriction in many contexts.

[EricTetz]

Since I needed it for my project, I wrote an MP3 recorder that works in mono or stereo. It makes no attempt to emulate the MediaRecorder API. It's using lamejs, so it's roughly twice the size of this library. But it's easier to use and supports stereo.