Audio Measure Audio Latency

Hello. I currently work on a project to make an instrument app and build it in different platform of devices (mobile and desktop). I want to do a research and get some data of audio latency from the devices that my app installed by triggering a button in my app. So what method in Unity that I should use to measure the audio latency? Thank you.

 

You can compute length of time of OnAudioFilterRead's data buffer based on its size, channels and current output sample rate
That should give you rough estimate of time needed to process smallest chunk of audio of common AudioSource - at least that's what unity exposes to user

 

using dspTimeSettings?

 

even easier - similarly as here: https://github.com/keijiro/VJ02/blo...e/Assets/Reaktion/Utility/NativeAudioInput.cs
(you dont have to set dsp buffer sizes if you don't want to, just get their sizes with AudioSettings.GetDSPBufferSize)

 

How do I implemented AudioSettings.GetDSPBufferSize? Do the estimated latency unit is in miliseconds?

 

you implement AudioSettings.GetDSPBufferSize by calling it :

Code (CSharp):

1.             int bufferLength, numBuffers;
2.             AudioSettings.GetDSPBufferSize(out bufferLength, out numBuffers);

the computed latency is in seconds - you're dividing buffer size (number of samples) by sample rate (samples per 1 second)

 

Is buffer size amount different in different devices?

 

It might differ, yes
In general you should determine its value by calling GetDSPBufferSize

 

Okay I've tried it. BufferLength is value of buffer size from DSP Buffer Size settings. For example if you set DSP Buffer Size to "best latency" you will get 256 from every devices where the application installed. Otherwise, sample rate value is different for different devices.

 

Right, I should have been more precise:
you should be always determining the sizes by calling the function since the user can change the settings.

 

More information :

- Each device has its own "native buffer size" which if the buffer size used in Unity matches, it is better. On Android there is an API to ask for this. Some of the collected data https://superpowered.com/latency
- The website mentioned also has open source the way they calculate the latency on-device. (not just the native buffer size) You can learn from their code and integrate it into your game. They use auto-calibration which play a sound and record back multiple times, or use a loop back cable. IMO asking information from Unity is far from accurate of what the device can really achieve.
- Unity's Best Latency is still really bad on some device. Look at this video using Best Latency compared with manually creating the track to match the device's native sampling rate and buffer size. That's why I said in the last point what you hear from Unity is not the true potential of the device.

 

on some models, when I set the DSP Buffer size to Best latency, the music turns to electric current

 

someone can tell Why is that

 

Perhaps you should clarify a bit more what you mean with "turns to electric current"