yumoqing
1832672081
- MTAudioProcessingTap captures audio samples from AVPlayer's audio track - Audio samples written to AVAssetWriter alongside video frames - First frame PTS used as session start (fixes duration stretch) - Cleaned up unused properties
306 lines
13 KiB
Swift
306 lines
13 KiB
Swift
#if os(iOS)
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import Foundation
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import AVFoundation
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import UIKit
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import MediaToolbox
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/// iOS 录制器 — 从 AVPlayer 播放输出捕获视频帧 + 音频，写入 MP4
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@MainActor
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final class HLSRecorder: ObservableObject {
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@Published var isRecording = false
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@Published var durationText = "00:00"
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var onRecordingSaved: ((URL) -> Void)?
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var onError: ((String) -> Void)?
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private var assetWriter: AVAssetWriter?
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private var videoInput: AVAssetWriterInput?
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private var audioInput: AVAssetWriterInput?
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private var videoOutput: AVPlayerItemVideoOutput?
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private var displayLink: CADisplayLink?
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private var startTime: Date?
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private var timer: Timer?
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private var outputURL: URL?
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private var firstPTS: CMTime?
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private var audioTapID: MTAudioProcessingTapID?
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func startRecording(url: URL, player: AVPlayer) {
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guard !isRecording, let item = player.currentItem else { return }
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isRecording = true
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startTime = Date()
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firstPTS = nil
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timer = Timer.scheduledTimer(withTimeInterval: 1, repeats: true) { [weak self] _ in
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Task { @MainActor in
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guard let self, let start = self.startTime else { return }
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let elapsed = Int(Date().timeIntervalSince(start))
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self.durationText = String(format: "%02d:%02d:%02d", elapsed / 3600, (elapsed % 3600) / 60, elapsed % 60)
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}
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}
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let docs = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)[0]
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outputURL = docs.appendingPathComponent("MiniPlayer_Recording_\(Int(Date().timeIntervalSince1970)).mp4")
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Task { await startCapture(item: item, player: player) }
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}
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func stopRecording() {
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guard isRecording else { return }
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isRecording = false
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timer?.invalidate()
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displayLink?.invalidate()
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videoOutput = nil
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videoInput?.markAsFinished()
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audioInput?.markAsFinished()
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assetWriter?.finishWriting { [weak self] in
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DispatchQueue.main.async {
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guard let self, let url = self.outputURL else { return }
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let status = self.assetWriter?.status ?? .unknown
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NSLog("[MiniPlayer] AVAssetWriter finished: %d", status.rawValue)
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if status == .completed {
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let attrs = try? FileManager.default.attributesOfItem(atPath: url.path)
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let size = (attrs?[.size] as? Int64) ?? 0
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NSLog("[MiniPlayer] Recorded: %lld bytes", size)
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self.onRecordingSaved?(url)
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} else {
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let err = self.assetWriter?.error?.localizedDescription ?? "unknown"
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self.onError?("Export: \(err)")
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try? FileManager.default.removeItem(at: url)
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}
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}
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}
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}
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// MARK: - Capture setup
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private func startCapture(item: AVPlayerItem, player: AVPlayer) async {
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guard let outputURL else { return }
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do {
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let writer = try AVAssetWriter(url: outputURL, fileType: .mp4)
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// Natural size from asset
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var size = CGSize(width: 1280, height: 720)
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if let tracks = try? await item.asset.load(.tracks),
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let videoTrack = tracks.first(where: { $0.mediaType == .video }) {
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let ns = try? await videoTrack.load(.naturalSize)
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if let ns, ns.width > 0 { size = ns }
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}
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// Video input
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let videoSettings: [String: Any] = [
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AVVideoCodecKey: AVVideoCodecType.h264,
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AVVideoWidthKey: size.width,
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AVVideoHeightKey: size.height,
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AVVideoCompressionPropertiesKey: [
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AVVideoAverageBitRateKey: 2_000_000,
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AVVideoProfileLevelKey: AVVideoProfileLevelH264HighAutoLevel
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]
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]
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let vidInput = AVAssetWriterInput(mediaType: .video, outputSettings: videoSettings)
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vidInput.expectsMediaDataInRealTime = true
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guard writer.canAdd(vidInput) else {
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throw NSError(domain: "Rec", code: 1, userInfo: [NSLocalizedDescriptionKey: "Cannot add video input"])
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}
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writer.add(vidInput)
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self.videoInput = vidInput
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// Audio input
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let audioSettings: [String: Any] = [
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AVFormatIDKey: kAudioFormatMPEG4AAC,
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AVSampleRateKey: 44100,
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AVNumberOfChannelsKey: 2,
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AVEncoderBitRateKey: 128_000
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]
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let audInput = AVAssetWriterInput(mediaType: .audio, outputSettings: audioSettings)
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audInput.expectsMediaDataInRealTime = true
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guard writer.canAdd(audInput) else {
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throw NSError(domain: "Rec", code: 2, userInfo: [NSLocalizedDescriptionKey: "Cannot add audio input"])
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}
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writer.add(audInput)
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self.audioInput = audInput
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// MTAudioProcessingTap on the player item's audio track
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installAudioTap(on: item)
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// Video output from player
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let pixAttrs: [String: Any] = [
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kCVPixelBufferPixelFormatTypeKey as String: kCVPixelFormatType_32BGRA,
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kCVPixelBufferWidthKey as String: size.width,
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kCVPixelBufferHeightKey as String: size.height
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]
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let vo = AVPlayerItemVideoOutput(pixelBufferAttributes: pixAttrs)
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vo.suppressesPlayerRendering = false
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item.add(vo)
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self.videoOutput = vo
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writer.startWriting()
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// session start will be set on first frame
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self.assetWriter = writer
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displayLink = CADisplayLink(target: self, selector: #selector(captureFrame))
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displayLink?.preferredFrameRateRange = CAFrameRateRange(minimum: 15, maximum: 30, preferred: 30)
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displayLink?.add(to: .main, forMode: .common)
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NSLog("[MiniPlayer] Capture started: %@", outputURL.path)
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} catch {
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await MainActor.run {
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self.isRecording = false
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self.timer?.invalidate()
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self.onError?(error.localizedDescription)
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}
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}
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}
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// MARK: - Audio tap
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private func installAudioTap(on item: AVPlayerItem) {
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guard let audioTrack = item.asset.tracks(withMediaType: .audio).first else {
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NSLog("[MiniPlayer] No audio track found")
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return
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}
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var callbacks = MTAudioProcessingTapCallbacks(
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version: kMTAudioProcessingTapCallbacksVersion_0,
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clientInfo: Unmanaged.passUnretained(self).toOpaque(),
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init: { tap, clientInfo, tapStorageOut in
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tapStorageOut?.pointee = clientInfo
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},
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finalize: { _ in },
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prepare: { _, _, _ in },
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unprepare: { _, _, _ in },
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process: { tap, numberFrames, flags, bufferListInOut, numberFramesOut, flagsOut in
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guard let clientInfo = MTAudioProcessingTapGetStorage(tap) else {
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numberFramesOut.pointee = 0
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return
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}
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let recorder = Unmanaged<HLSRecorder>.fromOpaque(clientInfo).takeUnretainedValue()
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recorder.processAudio(tap: tap, numberFrames: numberFrames, flags: flags,
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bufferListInOut: bufferListInOut,
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numberFramesOut: numberFramesOut, flagsOut: flagsOut)
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}
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)
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var tap: Unmanaged<MTAudioProcessingTap>?
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let status = MTAudioProcessingTapCreate(kCFAllocatorDefault, &callbacks,
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kMTAudioProcessingTapCreationFlag_PreEffects, &tap)
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guard status == noErr, let audioTap = tap?.takeRetainedValue() else {
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NSLog("[MiniPlayer] MTAudioProcessingTapCreate failed: %d", status)
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return
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}
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let inputParams = AVMutableAudioMixInputParameters(track: audioTrack)
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inputParams.audioTapProcessor = audioTap
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let audioMix = AVMutableAudioMix()
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audioMix.inputParameters = [inputParams]
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item.audioMix = audioMix
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NSLog("[MiniPlayer] Audio tap installed")
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}
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private func processAudio(tap: MTAudioProcessingTap, numberFrames: CMItemCount, flags: MTAudioProcessingTapFlags,
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bufferListInOut: UnsafeMutablePointer<AudioBufferList>,
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numberFramesOut: UnsafeMutablePointer<CMItemCount>,
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flagsOut: UnsafeMutablePointer<MTAudioProcessingTapFlags>) {
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// Get source audio
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var sourceFlags = flags
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var timeRange = CMTimeRange()
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let status = MTAudioProcessingTapGetSourceAudio(tap, numberFrames, bufferListInOut,
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flagsOut, &timeRange, numberFramesOut)
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guard status == noErr, let input = audioInput, input.isReadyForMoreMediaData else {
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flagsOut.pointee = flags
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return
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}
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// Create CMSampleBuffer from the audio buffer list
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let pts = timeRange.start
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var asbd = AudioStreamBasicDescription()
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MTAudioProcessingTapGetStreamDescription(tap, &asbd)
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var formatDesc: CMAudioFormatDescription?
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CMAudioFormatDescriptionCreate(allocator: kCFAllocatorDefault, asbd: &asbd,
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layoutSize: 0, layout: nil, 0, nil, nil,
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formatDescriptionOut: &formatDesc)
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guard let fd = formatDesc else { return }
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var sampleBuffer: CMSampleBuffer?
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let numSamples = numberFramesOut.pointee
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var timing = CMSampleTimingInfo(duration: CMTime(value: CMTimeValue(numSamples), timescale: CMTimeScale(asbd.mSampleRate)),
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presentationTimeStamp: pts, decodeTimeStamp: .invalid)
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CMSampleBufferCreate(allocator: kCFAllocatorDefault, dataBuffer: nil, dataReady: false,
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makeDataReadyCallback: nil, refcon: nil, formatDescription: fd,
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sampleCount: numSamples, sampleTimingEntryCount: 1,
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sampleTimingArray: &timing, sampleSizeEntryCount: 0,
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sampleSizeArray: nil, sampleBufferOut: &sampleBuffer)
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guard var sb = sampleBuffer else { return }
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// Copy audio data into the sample buffer
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let bufList = bufferListInOut.pointee
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var blockBuffer: CMBlockBuffer?
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CMBlockBufferCreateWithMemoryBlock(
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allocator: kCFAllocatorDefault,
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memoryBlock: nil,
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blockLength: Int(bufList.mBuffers.mDataByteSize),
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blockAllocator: kCFAllocatorDefault,
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customBlockSource: nil,
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offsetToData: 0,
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dataLength: Int(bufList.mBuffers.mDataByteSize),
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flags: 0,
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blockBufferOut: &blockBuffer
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)
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if let bb = blockBuffer {
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CMBlockBufferReplaceDataBytes(with: bufList.mBuffers.mData!, blockBuffer: bb,
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offsetIntoDestination: 0, dataLength: Int(bufList.mBuffers.mDataByteSize))
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CMSampleBufferSetDataBuffer(&sb, newValue: bb)
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input.append(sb)
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}
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}
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// MARK: - Video frame capture
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@objc private func captureFrame() {
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guard let writer = assetWriter, let vo = videoOutput, let vidInput = videoInput else { return }
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let itemTime = vo.itemTime(forHostTime: CACurrentMediaTime())
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guard vo.hasNewPixelBuffer(forItemTime: itemTime),
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let buf = vo.copyPixelBuffer(forItemTime: itemTime, itemTimeForDisplay: nil)
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else { return }
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// Start session on first frame
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if writer.status == .unknown {
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writer.startSession(atSourceTime: itemTime)
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firstPTS = itemTime
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NSLog("[MiniPlayer] Session started at PTS: %.3f", itemTime.seconds)
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}
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guard vidInput.isReadyForMoreMediaData else { return }
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var timing = CMSampleTimingInfo(
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duration: CMTime(value: 1, timescale: 30),
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presentationTimeStamp: itemTime,
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decodeTimeStamp: .invalid
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)
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var formatDesc: CMFormatDescription?
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CMVideoFormatDescriptionCreateForImageBuffer(allocator: kCFAllocatorDefault,
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imageBuffer: buf, formatDescriptionOut: &formatDesc)
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guard let fd = formatDesc else { return }
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var sampleBuffer: CMSampleBuffer?
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CMSampleBufferCreateReadyWithImageBuffer(allocator: kCFAllocatorDefault, imageBuffer: buf,
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formatDescription: fd, sampleTiming: &timing,
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sampleBufferOut: &sampleBuffer)
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if let sb = sampleBuffer {
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vidInput.append(sb)
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}
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}
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}
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#endif
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