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- //
- // SVNPlayer.swift
- // WYNDR
- //
- // Created by Aaron Dean Bikis on 5/24/17.
- // Copyright © 2017 7apps. All rights reserved.
- //
- import Foundation
- import AudioToolbox
- class SVNPlayer: SVNPlayback {
- var queue: AudioQueueRef?
- var audioFormat: AudioStreamBasicDescription!
- var playbackFile: AudioFileID?
- var packetDesc: AudioStreamPacketDescription!
- var isDone = false
- var packetPosition: Int64 = 0
- var numPacketsToRead = UInt32()
- private let callback: AudioQueueOutputCallback = { aqData, inAQ, inBuffer in
- guard let userData = aqData else { return }
- let audioPlayer = Unmanaged<SVNPlayer>.fromOpaque(userData).takeUnretainedValue()
- var buffer = inBuffer.pointee
- if audioPlayer.isDone { return }
- var numBytes: UInt32 = 0
- var nPackets = audioPlayer.numPacketsToRead
- var code = AudioFileReadPacketData(audioPlayer.playbackFile!, false, &numBytes, &audioPlayer.packetDesc!, audioPlayer.packetPosition, &nPackets, buffer.mAudioData)
- // code = AudioFileReadPackets(audioPlayer.playbackFile!, false, &numBytes, nil, audioPlayer.packetPosition!, &nPackets, buffer.mAudioData)
- print(code)
- if nPackets > 0 {
- buffer.mAudioDataByteSize = numBytes
- AudioQueueEnqueueBuffer(inAQ, &buffer, nPackets, &audioPlayer.packetDesc!)
- audioPlayer.packetPosition += Int64(nPackets)
- } else {
- AudioQueueStop(inAQ, false)
- audioPlayer.isDone = true
- }
- }
- func prepareToPlayback(with fileURL: URL) throws {
- let pointer = UnsafeMutableRawPointer(Unmanaged.passUnretained(self).toOpaque()) // get an unmananged reference to self
- var format = AudioStreamBasicDescription()
- var formatSize = UInt32(MemoryLayout<AudioStreamBasicDescription>.stride)
- var audioFileID: AudioFileID? // open the recorded file
- try osStatus { AudioFileOpenURL(fileURL as CFURL, AudioFilePermissions.readPermission, 0, &audioFileID) }
- playbackFile = audioFileID // get the full audio data format from the file
- try osStatus { AudioFileGetProperty(playbackFile!, kAudioFilePropertyDataFormat, &formatSize, &format) }
- try osStatus { AudioQueueNewOutput(&format, callback, pointer, nil, nil, 0, &queue) }
- var bufferByteSize = UInt32()
- var numPacketsToRead = UInt32()
- try deriveBufferByteSize(with: playbackFile!,
- format: format,
- duration: 0.5,
- outBufferByteSize: &bufferByteSize,
- outNumPackets: &numPacketsToRead)
- let isFormatVBR = format.mBytesPerPacket == 0 || format.mFramesPerPacket == 0
- if isFormatVBR {
- packetDesc = AudioStreamPacketDescription(mStartOffset: 0, mVariableFramesInPacket: numPacketsToRead, mDataByteSize: UInt32(MemoryLayout<AudioStreamPacketDescription>.stride)) // this may fail i dunno
- } // we don't provide packet descriptions for constant bit rate formats (like linear PCM)
- packetDesc = AudioStreamPacketDescription()
- try copyEncoderCookieToQueue(with: playbackFile!, queue: &queue!)
- var bufferRef: AudioQueueBufferRef?
- isDone = false
- packetPosition = 0
- for _ in 0..<3 {
- try osStatus { AudioQueueAllocateBuffer(queue!, bufferByteSize, &bufferRef) }
- guard let buffer = bufferRef else { print("couldn't get buffer"); return }
- callback(pointer, queue!, buffer)
- if isDone {
- break
- }
- }
- }
- func start() throws {
- try osStatus { AudioQueueStart(queue!, nil) }
- repeat {
- CFRunLoopRunInMode(CFRunLoopMode.defaultMode, 0.25, false)
- } while !isDone
- CFRunLoopRunInMode(CFRunLoopMode.defaultMode, 2, false)
- isDone = true
- AudioQueueStop(queue!, true)
- //clean up
- AudioQueueDispose(queue!, true)
- AudioFileClose(playbackFile!)
- }
- // we only use time here as a guideline
- // we're really trying to get somewhere between 16K and 64K buffers, but not allocate too much if we don't need it
- func deriveBufferByteSize(with file: AudioFileID, format: AudioStreamBasicDescription, duration: Double, outBufferByteSize: inout UInt32, outNumPackets: inout UInt32) throws {
- // we need to calculate how many packets we read at a time, and how big a buffer we need.
- // we base this on the size of the packets in the file and an approximate duration for each buffer.
- //
- // first check to see what the max size of a packet is, if it is bigger than our default
- // allocation size, that needs to become larger
- var maxPacketSize: UInt32 = 0
- var propertySize = UInt32(MemoryLayout<UInt32>.size(ofValue: maxPacketSize))
- try osStatus { AudioFileGetProperty(file, kAudioFilePropertyPacketSizeUpperBound, &propertySize, &maxPacketSize) }
- let maxBufferSize: Int = 0x10000
- let minBufferSize: Int = 0x4000
- let uMaxBufferSize = UInt32(maxBufferSize)
- let uMinBufferSize = UInt32(minBufferSize)
- if format.mFramesPerPacket == 0 {
- let numPacketesForTime = format.mSampleRate / Double(format.mFramesPerPacket) * duration
- outBufferByteSize = UInt32(numPacketesForTime) * maxPacketSize
- } else {
- // if frames per packet is zero, then the codec has no predictable packet == time
- // so we can't tailor this (we don't know how many Packets represent a time period
- // we'll just return a default buffer size
- outBufferByteSize = uMaxBufferSize > maxPacketSize ? uMaxBufferSize : maxPacketSize
- }
- // limit the size to our default
- if outBufferByteSize > uMaxBufferSize && outBufferByteSize > maxPacketSize {
- outBufferByteSize = uMaxBufferSize
- }
- // make sure it doesnt get too small - we dont want to save small chunks to disk
- else if outBufferByteSize < uMinBufferSize {
- outBufferByteSize = uMinBufferSize
- }
- outNumPackets = outBufferByteSize / maxPacketSize
- }
- func copyEncoderCookieToQueue(with file: AudioFileID, queue: inout AudioQueueRef) throws {
- var propertySize = UInt32()
- try osStatus { AudioFileGetPropertyInfo(file, kAudioFilePropertyMagicCookieData, &propertySize, nil) }
- if propertySize > 0 {
- var magicCookie = UInt8(MemoryLayout<UInt8>.size(ofValue: UInt8(propertySize)))
- try osStatus { AudioFileGetProperty(file, kAudioFilePropertyMagicCookieData, &propertySize, &magicCookie) }
- try osStatus { AudioQueueSetProperty(queue, kAudioQueueProperty_MagicCookie, &magicCookie, propertySize) }
- }
- }
- }
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