NewContext can be called only once

[AkselsLedins]

Hello FYI,

It's may be related to 3459272

And maybe it belongs to : https://github.com/faiface/beep

I don't know I'm not sure

Thanks

[hajimehoshi]

I think this is an implementation issue in beep

@faiface ?

[hajimehoshi]

Looks like beep calls NewPlayer only once in Init.

What kind of code are you trying to execute?

[AkselsLedins]

https://github.com/HowlSlack/app/blob/master/howl/audio.go#L20

It's a pretty simple app that reads incoming messages from a slack channel and then reads them out loud.
But I use beep that internally use your awesome lib.

I should propose to make a go.mod file for faiface/beep to avoid breaking changes.

@faiface

[hajimehoshi]

My guess is that beep's speaker.Init must be called only once, thought this is not documented. Actually Oto doesn't make this (whether oto.NewPlayer is called multiple times or not) explicit, so beep is not to blame. It depends on @faiface how to solve this problem: allow to call speaker.Init multiple times by fixing implementation, or do not allow explicitly.

[AkselsLedins]

Thank you @hajimehoshi for your time.
I really appreciate your work.

[hajimehoshi]

Oh have you solved this?

Thank you for compliments!

[AkselsLedins]

HowlSlack/app@cfc24b3

I did what you suggested. The issue is that this way the speaker has a fixed sample rate. Imagine you receive audio from multiple sources with different sample rates: that could not work.

I did a workaround to resample the audio streams:

HowlSlack/app@74253c7

Only thing that is mysterious to me is that I ask an audio stream with 22050 sample rate to AWS Polly I need to set the speaker's sample rate to 12000 in order to play the sound correctly. And if I ask an audio stream with a 16000 sample rate I need to set the speaker sample rate to 8000 in order to play it properly.

IMHO, But all of this is more a problem in my code, or aws polly, or beep package issue than oto

[faiface]

@AkselsLedins Yeah, resampling is what you're supposed to do when you have different sample rates.

Btw, @hajimehoshi, in Beep, you're supposed to call Init once at the beginning, but you're also allowed to call it later to reset the speaker and change configuration, such as sample rate, etc. How would that be achieved now?

[hajimehoshi]

you're also allowed to call it later to reset the speaker and change configuration, such as sample rate, etc. How would that be achieved now?

Oto doesn't allow it? Now unfortunately it is impossible to reset the sample rate so far.

[faiface]

So, Oto does or does not allow it? It did allow it before, and Beep was using that.

[hajimehoshi]

No, Oto doesn't allow it. Even if you could do it, you were just lucky...

Of course we can change the specification and fix the implementation (perhaps we wouldn't need any change but at least we need to double-check). However, IMHO, I don't think changing sample-rate is an important feature...

[cswank]

Changing sample rate is important for my app (GitHub.com/cswank/mcli). I have a collection of flac files that I bought from Bandcamp and so far there are 3 different sample rates in the collection. Calling beep’s speaker.Close() and then speaker.Init() with a new sample rate works fine on a Linux machine but hangs somewhere in the oto code on MacOS. I’ll be digging in to find out more, but I thought I’d just mention the fact for now.

[hajimehoshi]

Please see #149 for the discussion to implement this.

[cswank]

Thank you for the reply, that's good to know.