audio hiccup when hovering mouse above youtube video thumbnail in Chrome on MacOS

---
devices:
  samplerate: 44100
  chunksize: 1024
  enable_rate_adjust: true
  capture:
    type: CoreAudio
    device: "BlackHole 2ch"
    channels: 2
    format: F32
  playback:
    type: CoreAudio
    channels: 2
    device: "MacBook Pro Speakers"
    format: F32
    exclusive: true

2026-03-03 01:16:57.965739 DEBUG [camillalib::coreaudiodevice] <src/coreaudiodevice.rs:1021> Rate watcher, measured sample rate is 44104.6 Hz.
2026-03-03 01:16:58.987274 DEBUG [camillalib::coreaudiodevice] <src/coreaudiodevice.rs:998> Measured sample rate is 44100.1 Hz.
2026-03-03 01:16:58.987342 DEBUG [camillalib::coreaudiodevice] <src/coreaudiodevice.rs:1021> Rate watcher, measured sample rate is 44103.3 Hz.
2026-03-03 01:17:00.009002 DEBUG [camillalib::coreaudiodevice] <src/coreaudiodevice.rs:998> Measured sample rate is 44098.1 Hz.

import Foundation
import CoreAudio

// --- Configuration ---
let inputDeviceName = "BlackHole 2ch"
let outputDeviceName = "MacBook Pro Speakers"
let bufferSize: UInt32 = 1024 * 128 // 128KB buffer

class AudioCircle {
    var data = UnsafeMutableRawPointer.allocate(byteCount: Int(bufferSize), alignment: MemoryLayout<Float>.alignment)
    var writeOffset: Int = 0
    var readOffset: Int = 0
}
let sharedBuffer = AudioCircle()

// --- Helper: Find Device ID ---
func findDeviceID(named name: String) -> AudioDeviceID? {
    var propertyAddress = AudioObjectPropertyAddress(
        mSelector: kAudioHardwarePropertyDevices,
        mScope: kAudioObjectPropertyScopeGlobal,
        mElement: kAudioObjectPropertyElementMain
    )
    var dataSize: UInt32 = 0
    AudioObjectGetPropertyDataSize(AudioObjectID(kAudioObjectSystemObject), &propertyAddress, 0, nil, &dataSize)
    let deviceCount = Int(dataSize) / MemoryLayout<AudioDeviceID>.size
    var deviceIDs = [AudioDeviceID](repeating: 0, count: deviceCount)
    AudioObjectGetPropertyData(AudioObjectID(kAudioObjectSystemObject), &propertyAddress, 0, nil, &dataSize, &deviceIDs)
    
    for id in deviceIDs {
        var nameSize = UInt32(MemoryLayout<CFString?>.size)
        var deviceName: CFString?
        var nameAddress = AudioObjectPropertyAddress(
            mSelector: kAudioDevicePropertyDeviceNameCFString,
            mScope: kAudioObjectPropertyScopeGlobal,
            mElement: kAudioObjectPropertyElementMain
        )
        AudioObjectGetPropertyData(id, &nameAddress, 0, nil, &nameSize, &deviceName)
        if let nameStr = deviceName as String?, nameStr == name { return id }
    }
    return nil
}

// 1. Get Device IDs
guard let inputID = findDeviceID(named: inputDeviceName),
      let outputID = findDeviceID(named: outputDeviceName) else {
    print("Devices not found."); exit(1)
}

// 2. Input Callback (Device A -> Buffer)
let inputProc: AudioDeviceIOProc = { (inDevice, inNow, inInputData, inInputTime, outOutputData, inOutputTime, inClientData) -> OSStatus in
    let ring = Unmanaged<AudioCircle>.fromOpaque(inClientData!).takeUnretainedValue()
    
    // Access the first buffer in the list
    let inputBuf = inInputData.pointee.mBuffers
    if let src = inputBuf.mData {
        let size = Int(inputBuf.mDataByteSize)
        
        // Simple wrap-around logic
        if ring.writeOffset + size <= Int(bufferSize) {
            memcpy(ring.data + ring.writeOffset, src, size)
        }
        ring.writeOffset = (ring.writeOffset + size) % Int(bufferSize)
    }
    
    return noErr
}

// 3. Output Callback (Buffer -> Device B)
let outputProc: AudioDeviceIOProc = { (inDevice, inNow, inInputData, inInputTime, outOutputData, inOutputTime, inClientData) -> OSStatus in
    let ring = Unmanaged<AudioCircle>.fromOpaque(inClientData!).takeUnretainedValue()
    
    // Corrected access: Get the pointer to the AudioBuffer within the AudioBufferList
    let outBufferList = outOutputData.pointee
    let size = Int(outBufferList.mBuffers.mDataByteSize)
    
    if let dest = outBufferList.mBuffers.mData {
        if ring.readOffset + size <= Int(bufferSize) {
            memcpy(dest, ring.data + ring.readOffset, size)
        }
        ring.readOffset = (ring.readOffset + size) % Int(bufferSize)
    }
    
    return noErr
}

// 4. Register and Start
var inputProcID: AudioDeviceIOProcID?
var outputProcID: AudioDeviceIOProcID?
let context = Unmanaged.passUnretained(sharedBuffer).toOpaque()

// Create IO Procs
AudioDeviceCreateIOProcID(inputID, inputProc, context, &inputProcID)
AudioDeviceCreateIOProcID(outputID, outputProc, context, &outputProcID)

// Start Hardware
AudioDeviceStart(inputID, inputProcID)
AudioDeviceStart(outputID, outputProcID)

print(" CoreAudio Router Active: \(inputDeviceName) -> \(outputDeviceName)")
print("Check Audio MIDI Setup to ensure both are at the same Sample Rate.")
CFRunLoopRun()