Add method to import/export audio track from/to external

[Nemo-G]

Make package work with other sound engine.

1. Add GetData method so that data can be pulled from audio track
2. Add UnsafeSetData method so that we can feed external data into audio track

[unity-cla-assistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.

---

Nemo Guan seems not to be a GitHub user. You need a GitHub account to be able to sign the CLA. If you have already a GitHub account, please add the email address used for this commit to your account.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}

[Nemo-G]

Hi @karasusan , please refer to this issue for details.

[karasusan]

Thanks for your contribution!

I have a question, AudioStreamTrack already has SetData API, why do you want to add UnsafeSetData?

[Nemo-G]

Thanks for your contribution!

I have a question, AudioStreamTrack already has SetData API, why do you want to add UnsafeSetData?

This is because that inside SetData, NativeArray is used. And the allocator limit the caller context to be a Unity managed thread. However this API would be called inside Wwise Plugin C++ which using NativeArray(NativeContainer) will give a complier error.

[karasusan]

And the allocator limit the caller context to be a Unity managed thread.

Oh, I misunderstood that NativeArray is thread safe. Do you mean your issue is related this post in Unity Forum? https://forum.unity.com/threads/is-nativearray-thread-safe-for-its-allocation-and-deallocation.822846/

I would like to fix SetData method to make thread-safe instead of creating new method.

[karasusan]

How about Span in .Net? We may can replace Span instead of NativeArray.

[Nemo-G]

@karasusan You mean you want to change NativeArray data structure to Span in the original SetData ? I think that seems better and by that time we don't need add UnsafeSetData.

I think maybe we can merge it and when Span change is ready, we remove this? Or you would like me to update this PR and modify SetData directly?

[karasusan]

@Nemo-G I'm going to fix SetData, and if it works well, we can remove this PR.

[karasusan]

I fixed the issue in this draft PR. https://github.com/Unity-Technologies/com.unity.webrtc/pull/926

[karasusan]

@Nemo-G One question, you added GetData method in the AudioStreamTrack class, but I think we should make a delegate method to fetch audio buffer from an other peer. What do you think about that?

[Nemo-G]

@Nemo-G One question, you added GetData method in the AudioStreamTrack class, but I think we should make a delegate method to fetch audio buffer from an other peer. What do you think about that?

@karasusan

That sounds good. I'm fine with the delegation. In fact GetData in the PR, is not a good function name as it actually feeds the data to track instead of getting data. And this method implicitly assumes that the _streamRenderer is correctly initialized.

But I would like to point out that the delegation should be used only when there is no internally attached audio clip/source to the AudioStreamTrack. One track now only allow one source. Because of this, maybe the delegator could be added into the AudioStreamTrack constructor? Like new AudioStreamTrack( AudioDelegator delegator) as a new type of track?

[karasusan]

@Nemo-G I agree with you. I'm going to try your idea that making the new constructor with a callback argument.

[karasusan]

I made a PR for onReceive delegation. https://github.com/Unity-Technologies/com.unity.webrtc/pull/927

[karasusan]

@Nemo-G I pushed two draft PR but I would like to know your issues are fixed by these changes. Can you review them?

One note, if you want to check on your environment, you need to replace native plugins with this commit. https://github.com/Unity-Technologies/com.unity.webrtc/compare/main...chore/update-plugin

[Nemo-G]

@Nemo-G I pushed two draft PR but I would like to know your issues are fixed by these changes. Can you review them?

One note, if you want to check on your environment, you need to replace native plugins with this commit. main...chore/update-plugin

Hi @karasusan, I'm fine with those changes. It fully meets my demands.

I'll try with your latest libwebrtc later.

[karasusan]

@Nemo-G Thanks for checking. I am opening these draft PRs.

[karasusan]

We merged other PRs to fix this issue. I am closing this.