PublishCustomMic

Custom Microphone Publishing

This example demonstrates passing custom video data into the R5Stream.

Example Code

• BaseTest.swift
• PublishCustomMicTest.swift

Setup

To view this example, you simply need to open the example and subscribe to your stream from a second device. All video will be recorded, and the microphone audio will have its volume modified before being sent out.

Attach a Custom Audio Source

Instead of using an R5Microphone, this example uses a custom video source, the GainWobbleMic. This increases and decreases the gain between double volume to muted and back. It does this by extending the R5Microphone class and intercepting the processData method.

This method recieves an NSData object of raw audio samples - each byte in it being a single, mono sample - and a timestamp in milliseconds with the 0 point being the start of the stream. The data object is passed by reference, so it needs to be modified in place - by assigning new values to its internal array, and not assiging a object - which would just overwrite the reference.

var s: Int
var val: UInt8
let data = samples?.mutableBytes
let length: Int = (samples?.length)!
for i in 0...length {
  val = (data?.advanced(by: i).load(as: UInt8.self))!
  s = Int(Float(val) * self.gain)
  val = UInt8(min(s, Int(UInt8.max)))
  data?.advanced(by: i).storeBytes(of: val, as: UInt8.self)
}

PublishCustomMicTest.swift #74

This example amplifies the value of each byte according to the gain value - clamping the value to keep it from wrapping around when being converted back to a byte. This function could also be used as a timing device to provide completely separate audio.