Files
KMix_Pro/KJamsClone/Player.swift
T
2026-11-06 08:32:48 +00:00

526 lines
32 KiB
Swift

import SwiftUI
import AVFoundation
import CryptoKit
import CoreImage
import AudioToolbox
import CoreAudio
/// CDG follows consumed source frames, so tempo adjustment preserves graphics timing.
@MainActor final class Player: ObservableObject {
@Published var image: CGImage?
var onWillStartPlayback: (() -> Double)?
var onPlaybackReady: (() -> Void)?
private var pendingPlayback: Task<Void,Never>?
@Published private(set) var waitingForBackground = false
var audioPlaybackStarted: Bool { node.isPlaying }
var onGlobalMixChanged: ((GlobalMix) -> Void)?
var jogSecondsPerTurn: Double = 2
var nudgeStep: Double = 0.05
@Published private(set) var cuePosition: Double = 0
@Published private(set) var hotCues: [Double?] = [nil,nil,nil,nil]
@Published private(set) var loopIn: Double?
@Published private(set) var loopOut: Double?
@Published var loopEnabled = false
var isShowScreen: Bool { slideImage != nil }
var canJog: Bool { currentSongID != nil && duration > 0 }
/// Read the audio clock for display frames without publishing the entire player at 60 Hz.
var displayTime: Double {
guard playing,node.isPlaying,let file,let render = node.lastRenderTime,
let current = node.playerTime(forNodeTime:render) else { return time }
let now = mach_absolute_time()
let elapsed = render.isHostTimeValid && now >= render.hostTime ? min(0.1,AVAudioTime.seconds(forHostTime:now-render.hostTime)) : 0
let position = anchor+Double(current.sampleTime)/file.processingFormat.sampleRate+elapsed*tempo
return min(duration,max(0,position))
}
func stopDeck() {
guard canJog else { return }
pauseDeck();loopEnabled = false;seek(0)
}
func setCue(at seconds: Double? = nil) {
guard canJog else { return }
if let seconds { guard seconds.isFinite else { return };cuePosition = min(duration,max(0,seconds)) }
else { tick();cuePosition = time }
}
func returnToCue() { guard canJog else { return };pauseDeck();seek(cuePosition) }
private func pauseDeck() {
cancelPendingPlayback()
if slideImage != nil,playing { time = min(duration,slideAnchor+ProcessInfo.processInfo.systemUptime-slideStart);slideAnchor = time }
else if let file,playing,let render = node.lastRenderTime,let current = node.playerTime(forNodeTime:render) { time = min(duration,max(0,anchor+Double(current.sampleTime)/file.processingFormat.sampleRate)) }
node.pause();playing = false;timer?.invalidate();timer = nil
}
func hotCue(_ index: Int,clear: Bool = false) {
guard hotCues.indices.contains(index),canJog else { return }
if clear { hotCues[index] = nil }
else if let value = hotCues[index] { seek(value) }
else { hotCues[index] = time }
}
func markLoopIn() { guard canJog else { return };loopIn = time;loopOut = nil;loopEnabled = false }
func markLoopOut() {
guard let loopIn,time-loopIn >= 0.1 else { return };loopOut = time;loopEnabled = true
}
func defineLoop(start: Double,end: Double) {
guard canJog,start.isFinite,end.isFinite,start >= 0,end <= duration,end-start >= 0.1-1e-9 else { return }
loopIn = start;loopOut = end;loopEnabled = true
}
func clearLoop() { loopEnabled = false;loopIn = nil;loopOut = nil }
func jog(_ seconds: Double) { guard seconds.isFinite,canJog else { return };seek(time+seconds) }
private var graphicsGeneration = UUID()
private var graphicsTask: Task<Void,Never>?
private var checkpointTask: Task<Void,Never>?
private var checkpoints = [Int:CDGDecoder]()
private var lastGraphicsPacket = -1
@Published private(set) var outputOpacity: Double = 1
@Published private(set) var fading = false
var fadeSeconds: Double = 3
var autoFade = true
private var fadeTask: Task<Void,Never>?
private var slideImage: CGImage?
private var slideStart = ProcessInfo.processInfo.systemUptime
private var slideAnchor: Double = 0
func showScreen(_ image: CGImage,seconds: Double,title: String,songID: Int64) {
stop();slideImage = image;self.image = image;duration = max(3,seconds);self.title = title;currentSongID = songID
slideAnchor = 0;slideStart = ProcessInfo.processInfo.systemUptime;playing = true;startTimer()
}
func fadeOutAndStop() {
guard duration > 0,!fading else { return };fading = true
let token = generation,start = ProcessInfo.processInfo.systemUptime,seconds = max(0.05,fadeSeconds),initial = outputOpacity
fadeTask = Task { [weak self] in
while !Task.isCancelled {
guard let self,self.generation == token else { return }
let fraction = min(1,(ProcessInfo.processInfo.systemUptime-start)/seconds)
self.setFade(initial*(1-fraction))
if fraction >= 1 { self.stop();return }
try? await Task.sleep(nanoseconds:16_666_667)
}
}
}
private func setFade(_ value: Double) { let next = min(1,max(0,value));if abs(outputOpacity-next) > 0.00001 { outputOpacity = next;node.volume = Float(next) } }
private var videoPlayer: AVPlayer?
private var videoOutput: AVPlayerItemVideoOutput?
private let videoContext = CIContext()
private var mixURL: URL { waveformCacheDirectory.deletingLastPathComponent().appendingPathComponent("GlobalMixer.json") }
private var restoringMix = true
private var persistsMix = true
func routeOutput(_ device: AudioDeviceID,firstChannel: Int = 0) throws {
guard let unit = engine.outputNode.audioUnit else { throw LibraryError.message("Audio output unavailable") }
var map = try DJAudioRouting.channelMap(channels:DJAudioDevice.channelCount(device),first:firstChannel)
var previousDevice = AudioDeviceID(0),bytes = UInt32(MemoryLayout<AudioDeviceID>.size)
_ = AudioUnitGetProperty(unit,kAudioOutputUnitProperty_CurrentDevice,kAudioUnitScope_Global,0,&previousDevice,&bytes)
func setMap(_ values: inout [Int32]) -> OSStatus {
values.withUnsafeMutableBytes { AudioUnitSetProperty(unit,kAudioOutputUnitProperty_ChannelMap,kAudioUnitScope_Input,0,$0.baseAddress!,UInt32($0.count)) }
}
// Channel-only changes can be applied by HAL without interrupting the player.
if previousDevice == device,setMap(&map) == noErr { return }
tick()
let running = engine.isRunning,resume = playing,position = time,wasWaiting = waitingForBackground
var previousMap = outputChannelMap()
cancelPendingPlayback();generation = UUID();node.stop();engine.stop()
do {
var value = device
let result = AudioUnitSetProperty(unit,kAudioOutputUnitProperty_CurrentDevice,kAudioUnitScope_Global,0,&value,UInt32(MemoryLayout.size(ofValue:value)))
guard result == noErr else { throw LibraryError.message("Audio routing failed (\(result))") }
let mapResult = setMap(&map)
guard mapResult == noErr else { throw LibraryError.message("Audio channel routing failed (\(mapResult))") }
if running || resume { try engine.start() }
if file != nil { schedule(at:position,play:resume,notifyPlayback:wasWaiting) }
} catch {
if previousDevice != 0 {
_ = AudioUnitSetProperty(unit,kAudioOutputUnitProperty_CurrentDevice,kAudioUnitScope_Global,0,&previousDevice,UInt32(MemoryLayout<AudioDeviceID>.size))
if !previousMap.isEmpty { _ = setMap(&previousMap) }
}
if running || resume { try? engine.start() }
if file != nil { schedule(at:position,play:resume && engine.isRunning,notifyPlayback:wasWaiting) }
throw error
}
}
func outputChannelMap() -> [Int32] {
guard let unit = engine.outputNode.audioUnit else { return [] }
var size: UInt32 = 0
guard AudioUnitGetPropertyInfo(unit,kAudioOutputUnitProperty_ChannelMap,kAudioUnitScope_Input,0,&size,nil) == noErr,size > 0 else { return [] }
var values = [Int32](repeating:-1,count:Int(size)/4)
let result = values.withUnsafeMutableBytes { AudioUnitGetProperty(unit,kAudioOutputUnitProperty_ChannelMap,kAudioUnitScope_Input,0,$0.baseAddress!,&size) }
return result == noErr ? values : []
}
struct GlobalMix: Codable, Equatable {
var volume: Double; var low: Double; var mid: Double; var high: Double; var filter: Double; var enabled: Bool
}
var globalMix: GlobalMix { .init(volume:volume,low:lowGain,mid:midGain,high:highGain,filter:filter,enabled:toneEnabled) }
private func saveMix() {
guard persistsMix,!restoringMix, let data = try? JSONEncoder().encode(globalMix) else { return }
try? FileManager.default.createDirectory(at:mixURL.deletingLastPathComponent(),withIntermediateDirectories:true)
try? data.write(to:mixURL,options:.atomic)
onGlobalMixChanged?(globalMix)
}
@Published private(set) var waveform = [Float]() { didSet { waveformRevision = UUID() } }
private(set) var waveformRevision = UUID()
@Published private(set) var waveformBands = [WaveformBands]()
@Published var inputGain: Double = 0 { didSet { tone.globalGain = Float(min(12,max(-12,inputGain))) } }
@Published var lowGain: Double = 0 { didSet { updateTone() } }
@Published var midGain: Double = 0 { didSet { updateTone() } }
@Published var highGain: Double = 0 { didSet { updateTone() } }
@Published var filter: Double = 0 { didSet { updateTone() } }
@Published var toneEnabled = true { didSet { updateTone() } }
@Published private(set) var leftLevel: Float = 0
@Published private(set) var rightLevel: Float = 0
private let tone = AVAudioUnitEQ(numberOfBands:4)
private let meter = AudioLevelMeter()
private var metering = false
@Published private(set) var waveformLoading = false
@Published private(set) var waveformUnavailable = false
@Published private(set) var waveformFromCache = false
@Published private(set) var waveformSaved = false
private let waveformCacheDirectory: URL
private var audioURL: URL?
var sourceAudioURL: URL? { audioURL }
private var waveformTask: Task<Void, Never>?
private var waveformGeneration = UUID()
@Published var playing = false
@Published var time: Double = 0
@Published var duration: Double = 0
@Published var title = "Select a song"
@Published var volume: Double = 0.8 { didSet { engine.mainMixerNode.outputVolume = Float(volume); saveMix() } }
@Published var repeating = false
@Published var pitch: Double = 0 { didSet { effect.pitch = Float(pitch * 100) } }
@Published var tempo: Double = 1 { didSet { effect.rate = Float(tempo) } }
@Published var graphicsOffset: Double = 0 { didSet { if graphicsOffset != oldValue { invalidateGraphics();render() } } }
private(set) var currentSongID: Int64?
var onFinished: (() -> Void)?
private let engine = AVAudioEngine()
private let node = AVAudioPlayerNode()
private let effect = AVAudioUnitTimePitch()
private var file: AVAudioFile?
private var anchor: Double = 0
private var generation = UUID()
private var cdg = Data()
private var decoder = CDGDecoder()
private var timer: Timer?
init(waveformCacheDirectory: URL? = nil, persistsMix: Bool = true) {
self.persistsMix = persistsMix
self.waveformCacheDirectory = waveformCacheDirectory ?? FileManager.default.urls(for:.applicationSupportDirectory,in:.userDomainMask)[0].appendingPathComponent("KJamsClone/Waveforms")
engine.attach(node);engine.attach(effect);engine.attach(tone)
if persistsMix,let data = try? Data(contentsOf:mixURL),let mix = try? JSONDecoder().decode(GlobalMix.self,from:data) {
volume = min(1,max(0,mix.volume));lowGain = min(12,max(-12,mix.low));midGain = min(12,max(-12,mix.mid));highGain = min(12,max(-12,mix.high));filter = min(1,max(-1,mix.filter));toneEnabled = mix.enabled
}
restoringMix = false;updateTone()
}
func refreshCachedWaveform() { if let audioURL { analyseWaveform(audioURL) } }
func reanalyseWaveform() { if let audioURL { analyseWaveform(audioURL,force:true) } }
func resetTone() { lowGain = 0; midGain = 0; highGain = 0; filter = 0; toneEnabled = true }
private func updateTone() {
AudioTone.configure(tone,sampleRate:file?.processingFormat.sampleRate ?? 44100,low:lowGain,mid:midGain,high:highGain,filter:filter,enabled:toneEnabled)
saveMix()
}
func load(_ song: Song, preference: SongPreference = .init(), startPlaying: Bool = true) throws {
stop()
do {
guard MediaByteCopy.nonempty(URL(fileURLWithPath:song.audio)) else { throw LibraryError.message("Audio file is empty or unavailable: \(song.title). Reimport the original media to repair the library copy.") }
let loaded = try AVAudioFile(forReading:URL(fileURLWithPath:song.audio))
let graphics = try song.cdg.map { try Data(contentsOf:URL(fileURLWithPath:$0)) } ?? Data()
guard loaded.length > 0 else { throw LibraryError.message("Audio file is empty") }
engine.connect(node,to:effect,format:loaded.processingFormat)
engine.connect(effect,to:tone,format:loaded.processingFormat)
engine.connect(tone,to:engine.mainMixerNode,format:loaded.processingFormat)
file = loaded; cdg = graphics; decoder = CDGDecoder();prepareGraphicsCheckpoints()
duration = Double(loaded.length)/loaded.processingFormat.sampleRate
title = song.title; currentSongID = song.id
pitch = preference.pitch; tempo = preference.tempo
updateTone()
let meter = self.meter
engine.mainMixerNode.installTap(onBus:0,bufferSize:1024,format:nil) { buffer, _ in meter.consume(buffer) }
metering = true
engine.mainMixerNode.outputVolume = Float(volume)
engine.prepare(); try engine.start()
schedule(at:0,play:startPlaying); startTimer(); tick()
if ["mp4","m4v","mov"].contains(URL(fileURLWithPath:song.audio).pathExtension.lowercased()) {
let item = AVPlayerItem(url:URL(fileURLWithPath:song.audio))
let output = AVPlayerItemVideoOutput(pixelBufferAttributes:[kCVPixelBufferPixelFormatTypeKey as String:kCVPixelFormatType_32BGRA])
item.add(output);videoOutput = output;videoPlayer = AVPlayer(playerItem:item);videoPlayer?.isMuted = true
}
audioURL = URL(fileURLWithPath:song.audio)
analyseWaveform(audioURL!)
} catch { stop(); throw error }
}
private func analyseWaveform(_ url: URL, force: Bool = false) {
waveformTask?.cancel()
let token = UUID();waveformGeneration = token;waveformLoading = true;waveformUnavailable = false
let directory = waveformCacheDirectory
waveformTask = Task.detached(priority:.utility) { [weak self] in
let result: Result<AudioWaveform.Analysis,Error>
var cached = false,saved = false
do {
if !force,let analysis = try? WaveformCache.load(audio:url,directory:directory) {
result = .success(analysis);cached = true;saved = true
} else {
let analysis = try AudioWaveform.analyse(url:url,cancelled:{ Task.isCancelled })
if !Task.isCancelled { saved = (try? WaveformCache.save(analysis,audio:url,directory:directory)) != nil }
result = .success(analysis)
}
} catch { result = .failure(error) }
guard !Task.isCancelled else { return }
let loadedFromCache = cached,analysisSaved = saved
await MainActor.run { [weak self] in
guard let self,self.waveformGeneration == token else { return }
self.waveformLoading = false;self.waveformFromCache = loadedFromCache;self.waveformSaved = analysisSaved
switch result {
case .success(let analysis):self.waveform = analysis.levels;self.waveformBands = analysis.bands
case .failure:self.waveformUnavailable = true
}
}
}
}
private func cancelPendingPlayback() { pendingPlayback?.cancel();pendingPlayback = nil;waitingForBackground = false }
private func startNodePlayback() {
cancelPendingPlayback()
let delay = onWillStartPlayback?() ?? 0
guard delay.isFinite,delay > 0 else { onPlaybackReady?();node.play();return }
waitingForBackground = true;let token = generation
pendingPlayback = Task { @MainActor [weak self] in
do { try await Task.sleep(nanoseconds:UInt64(min(15,delay)*1_000_000_000)+20_000_000) } catch { return }
guard let self,self.generation == token,self.playing else { return }
self.waitingForBackground = false;self.pendingPlayback = nil
self.onPlaybackReady?();self.node.play()
}
}
private func schedule(at seconds: Double, play: Bool,notifyPlayback: Bool = true) {
guard let file else { return }
cancelPendingPlayback();generation = UUID(); let token = generation
node.stop();if !fading { setFade(1) }
let rate = file.processingFormat.sampleRate
let start = min(file.length,max(0,AVAudioFramePosition(seconds*rate)))
anchor = Double(start)/rate; time = anchor
guard start < file.length else { playing = false; render(); return }
node.scheduleSegment(file,startingFrame:start,frameCount:AVAudioFrameCount(min(file.length-start,Int64(UInt32.max))),at:nil,completionCallbackType:.dataPlayedBack) { [weak self] _ in
Task { @MainActor in
guard let self, self.generation == token else { return }
if self.fading { return }
if self.loopEnabled,let start = self.loopIn { self.schedule(at:start,play:true) }
else if self.repeating { self.schedule(at:0,play:true) }
else {
self.playing = false; self.time = self.duration; self.render()
self.timer?.invalidate(); self.timer = nil; self.onFinished?()
}
}
}
if play { if notifyPlayback { startNodePlayback() } else { node.play() } }; playing = play; render()
}
private func startTimer() {
timer?.invalidate()
timer = Timer(timeInterval:1.0/30,repeats:true) { [weak self] _ in Task { @MainActor in self?.tick() } }
if let timer { RunLoop.main.add(timer,forMode:.common) }
}
func toggle() {
if slideImage != nil {
if playing { tick();slideAnchor = time;playing = false } else { if time >= duration { time = 0;slideAnchor = 0 };slideStart = ProcessInfo.processInfo.systemUptime;playing = true;startTimer() };return
}
guard file != nil else { return }
if playing { cancelPendingPlayback();tick(); node.pause(); playing = false }
else if time >= duration { schedule(at:0,play:true); startTimer() }
else { startNodePlayback(); playing = true; startTimer() }
}
func stop() {
cancelPendingPlayback()
graphicsGeneration = UUID();graphicsTask?.cancel();graphicsTask = nil;checkpointTask?.cancel();checkpointTask = nil;checkpoints = [:];lastGraphicsPacket = -1
cuePosition = 0;hotCues = [nil,nil,nil,nil];clearLoop()
fadeTask?.cancel();fadeTask = nil;fading = false;setFade(1);slideImage = nil
videoPlayer?.pause();videoPlayer = nil;videoOutput = nil
waveformTask?.cancel(); waveformTask = nil; waveformGeneration = UUID()
waveform = [];waveformBands = [];waveformLoading = false;waveformUnavailable = false;waveformFromCache = false;waveformSaved = false;audioURL = nil
generation = UUID(); timer?.invalidate(); timer = nil; node.stop(); engine.stop()
if metering { engine.mainMixerNode.removeTap(onBus:0); metering = false }
meter.reset(); leftLevel = 0; rightLevel = 0
engine.disconnectNodeOutput(node); engine.disconnectNodeOutput(effect); engine.disconnectNodeOutput(tone)
file = nil; playing = false; time = 0; anchor = 0; duration = 0; image = nil; currentSongID = nil; title = "Select a song"
}
func seek(_ value: Double) {
guard value.isFinite else { return }
invalidateGraphics()
if loopEnabled,let loopIn,let loopOut,(value < loopIn || value > loopOut) { loopEnabled = false }
if fading { fadeTask?.cancel();fadeTask = nil;fading = false;setFade(1) }
if slideImage != nil,value.isFinite { time = min(duration,max(0,value));slideAnchor = time;slideStart = ProcessInfo.processInfo.systemUptime;return }
guard file != nil, value.isFinite else { return }
schedule(at:min(max(value,0),duration),play:playing); startTimer()
}
private func render() {
if let slideImage { image = slideImage;return }
if let videoPlayer, let videoOutput {
let target = max(0,time+graphicsOffset)
if abs(videoPlayer.currentTime().seconds-target) > 0.08 {
videoPlayer.seek(to:CMTime(seconds:target,preferredTimescale:600),toleranceBefore:.zero,toleranceAfter:.zero)
}
if playing { videoPlayer.rate = Float(tempo) } else { videoPlayer.pause() }
if let pixels = videoOutput.copyPixelBuffer(forItemTime:videoPlayer.currentTime(),itemTimeForDisplay:nil) {
let frame = CIImage(cvPixelBuffer:pixels);image = videoContext.createCGImage(frame,from:frame.extent)
}
} else {
guard !cdg.isEmpty else { if image != nil { image = nil };return }
let seconds = max(0,time+graphicsOffset),target = min(cdg.count/24,Int(seconds*300))
guard target != lastGraphicsPacket || image == nil else { return }
guard graphicsTask == nil else { return }
if target < decoder.packetIndex || target-decoder.packetIndex > 900 {
var start = decoder
if target < decoder.packetIndex { start = checkpoints.keys.filter{$0 <= target}.max().flatMap{checkpoints[$0]} ?? CDGDecoder() }
else if let key = checkpoints.keys.filter({$0 <= target && $0 > decoder.packetIndex}).max(),let saved = checkpoints[key] { start = saved }
let initial = start,data = cdg,token = graphicsGeneration
graphicsTask = Task.detached(priority:.userInitiated) { [weak self] in
var decoded = initial;decoded.render(data,at:seconds,cancelled:{Task.isCancelled})
guard !Task.isCancelled else { return };let frame = decoded.image(),finished = decoded
await MainActor.run {
guard let self,self.graphicsGeneration == token else { return }
self.decoder = finished;self.lastGraphicsPacket = target;self.image = frame;self.graphicsTask = nil
}
}
} else { decoder.render(cdg,at:seconds);lastGraphicsPacket = target;image = decoder.image() }
}
}
private func tick() {
if slideImage != nil {
if playing { time = min(duration,slideAnchor+ProcessInfo.processInfo.systemUptime-slideStart) }
if playing,time >= duration,!fading {
if repeating { time = 0;slideAnchor = 0;slideStart = ProcessInfo.processInfo.systemUptime }
else { playing = false;timer?.invalidate();timer = nil;onFinished?() }
};return
}
let levels = meter.snapshot()
let left = playing ? levels.0 : 0,right = playing ? levels.1 : 0
if leftLevel != left { leftLevel = left };if rightLevel != right { rightLevel = right }
if playing, let file, let renderTime = node.lastRenderTime, let playerTime = node.playerTime(forNodeTime:renderTime) {
let next = min(duration,max(0,anchor+Double(playerTime.sampleTime)/file.processingFormat.sampleRate))
if abs(time-next) > 0.0001 { time = next }
if loopEnabled,let loopIn,let loopOut,time >= loopOut { schedule(at:loopIn,play:true);return }
}
if !fading { setFade(autoFade && fadeSeconds > 0 && duration > 0 ? min(1,max(0,(duration-time)/max(0.5,tempo)/fadeSeconds)) : 1) }
render()
}
private func invalidateGraphics() { graphicsGeneration = UUID();graphicsTask?.cancel();graphicsTask = nil;lastGraphicsPacket = -1 }
private func prepareGraphicsCheckpoints() {
guard !cdg.isEmpty else { return }
let data = cdg,interval = max(3000,(cdg.count/24)/180)
checkpointTask = Task.detached(priority:.utility) { [weak self] in
var decoder = CDGDecoder(),saved = [Int:CDGDecoder]()
for packet in stride(from:0,through:data.count/24,by:interval) {
guard !Task.isCancelled else { return };decoder.render(data,at:Double(packet)/300,cancelled:{Task.isCancelled});saved[decoder.packetIndex] = decoder
}
guard !Task.isCancelled else { return };let completed = saved
await MainActor.run { [weak self] in guard let self,self.cdg == data else { return };self.checkpoints = completed }
}
}
}
/// Streams fixed-size PCM chunks into a bounded RMS envelope, independent of playback.
/// A separate AVAudioFile keeps analysis away from the player's scheduling/read position.
enum AudioWaveform {
struct Analysis: Codable, Sendable { var levels: [Float]; var bands: [WaveformBands] }
static func read(url: URL, bins: Int = 4096, cancelled: () -> Bool = { false }) throws -> [Float] {
try analyse(url:url,bins:bins,cancelled:cancelled).levels
}
static func analyse(url: URL, bins: Int = 4096, cancelled: () -> Bool = { false }) throws -> Analysis {
guard bins > 0 else { return .init(levels:[],bands:[]) }
let file = try AVAudioFile(forReading: url, commonFormat: .pcmFormatFloat32, interleaved: false)
guard file.length > 0, let buffer = AVAudioPCMBuffer(pcmFormat: file.processingFormat, frameCapacity: 16384) else { return .init(levels:[],bands:[]) }
var energy = [Double](repeating: 0, count: bins)
var counts = [Int](repeating: 0, count: bins)
var position: Int64 = 0
let channels = Int(file.processingFormat.channelCount)
let rate = file.processingFormat.sampleRate
let lowAlpha = exp(-2*Double.pi*250/rate), highAlpha = exp(-2*Double.pi*2500/rate)
var lowState = [Double](repeating:0,count:channels), highState = lowState
var lows = [Double](repeating:0,count:bins), mids = lows, highs = lows
while position < file.length {
if cancelled() { throw CancellationError() }
try file.read(into: buffer, frameCount: AVAudioFrameCount(min(16384, file.length-position)))
let frames = Int(buffer.frameLength)
guard frames > 0, let data = buffer.floatChannelData else { break }
for frame in 0..<frames {
let bin = min(bins-1, Int((position+Int64(frame))*Int64(bins)/file.length))
var sum: Double = 0
for channel in 0..<channels {
let sample = Double(data[channel][frame])
if sample.isFinite {
sum += sample * sample
lowState[channel] = lowAlpha*lowState[channel]+(1-lowAlpha)*sample
highState[channel] = highAlpha*highState[channel]+(1-highAlpha)*sample
let low = lowState[channel], mid = highState[channel]-low, high = sample-highState[channel]
lows[bin] += low*low; mids[bin] += mid*mid; highs[bin] += high*high
}
}
energy[bin] += sum / Double(max(channels,1)); counts[bin] += 1
}
position += Int64(frames)
}
let rms = zip(energy, counts).map { $1 > 0 ? sqrt($0/Double($1)) : 0 }
let peak = rms.max() ?? 0
let levels = peak > 0 ? rms.map { Float(pow(min(1,$0/peak),0.7)) } : [Float](repeating:0,count:bins)
let bands = (0..<bins).map { i in WaveformBands(low:Float(sqrt(lows[i])),mid:Float(sqrt(mids[i])),high:Float(sqrt(highs[i]))) }
return .init(levels:levels,bands:bands)
}
}
struct WaveformBands: Codable, Sendable {
var low: Float
var mid: Float
var high: Float
}
/// Four real audio filters; the filter knob is low-pass left, bypass at centre, high-pass right.
enum AudioTone {
static func configure(_ eq: AVAudioUnitEQ, sampleRate: Double, low: Double, mid: Double, high: Double, filter: Double, enabled: Bool) {
eq.bypass = !enabled
let frequencies = [160.0,1000.0,6000.0]
let types: [AVAudioUnitEQFilterType] = [.lowShelf,.parametric,.highShelf]
for i in 0..<3 {
let band = eq.bands[i];band.filterType = types[i];band.frequency = Float(min(frequencies[i],sampleRate*0.4))
band.bandwidth = 1;band.gain = Float(min(12,max(-12,[low,mid,high][i])));band.bypass = false
}
let value = min(1,max(-1,filter))
let band = eq.bands[3];band.bypass = abs(value) < 0.01;band.bandwidth = 0.7
band.filterType = value < 0 ? .lowPass : .highPass
let frequency = value < 0 ? 20000*pow(0.004,-value) : 20*pow(400,value)
band.frequency = Float(min(sampleRate*0.45,max(20,frequency)))
}
}
/// The audio callback only updates a tiny locked snapshot; UI reads it on the existing clock.
final class AudioLevelMeter: @unchecked Sendable {
private let lock = NSLock()
private var levels: (Float,Float) = (0,0)
func consume(_ buffer: AVAudioPCMBuffer) {
guard let data = buffer.floatChannelData else { return }
let channels = Int(buffer.format.channelCount), frames = Int(buffer.frameLength)
var left: Float = 0, right: Float = 0
for i in 0..<frames {
left = max(left,abs(data[0][i]));right = max(right,abs(data[min(1,channels-1)][i]))
}
lock.lock();levels = (left,right);lock.unlock()
}
func snapshot() -> (Float,Float) { lock.lock();defer { lock.unlock() };return levels }
func reset() { lock.lock();levels = (0,0);lock.unlock() }
}
/// Persistent analysis cache: file path, size, modification time and analyser version form its key.
/// Invalid or obsolete entries are treated as misses, never as playback errors.
enum WaveformCache {
static func location(audio: URL,directory: URL) throws -> URL {
let values = try FileManager.default.attributesOfItem(atPath:audio.path)
let stamp = (values[.modificationDate] as? Date)?.timeIntervalSince1970 ?? 0
let size = (values[.size] as? NSNumber)?.int64Value ?? 0
let signature = "rgb-rms-v2-4096|\(audio.standardizedFileURL.path)|\(size)|\(stamp)"
let key = SHA256.hash(data:Data(signature.utf8)).map { String(format:"%02x",$0) }.joined()
return directory.appendingPathComponent(key+".waveform")
}
static func load(audio: URL,directory: URL) throws -> AudioWaveform.Analysis {
let url = try location(audio:audio,directory:directory)
let data = try Data(contentsOf:url)
guard data.count < 4_000_000 else { throw LibraryError.message("Invalid waveform cache") }
let analysis = try PropertyListDecoder().decode(AudioWaveform.Analysis.self,from:data)
guard analysis.levels.count == 4096,analysis.bands.count == 4096,
analysis.levels.allSatisfy({ $0.isFinite && $0 >= 0 && $0 <= 1 }),
analysis.bands.allSatisfy({ $0.low.isFinite && $0.mid.isFinite && $0.high.isFinite && $0.low >= 0 && $0.mid >= 0 && $0.high >= 0 }) else { throw LibraryError.message("Invalid waveform cache") }
return analysis
}
static func save(_ analysis: AudioWaveform.Analysis,audio: URL,directory: URL) throws {
try FileManager.default.createDirectory(at:directory,withIntermediateDirectories:true)
let encoder = PropertyListEncoder();encoder.outputFormat = .binary
try encoder.encode(analysis).write(to:location(audio:audio,directory:directory),options:.atomic)
}
}