class MediaPlayerNode
播放层UI(AVSampleBufferDisplayLayer)封装
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public var videoInHierarchy: Bool = false
public var updateVideoInHierarchy: ((Bool) -> Void)?
private var videoNode: MediaPlayerNodeDisplayNode
private var videoLayer: AVSampleBufferDisplayLayer?
private let videoQueue: Queue
public var snapshotNode: ASDisplayNode? {
didSet {
if let snapshotNode = oldValue {
snapshotNode.removeFromSupernode()
}
if let snapshotNode = self.snapshotNode {
snapshotNode.frame = self.bounds
self.insertSubnode(snapshotNode, at: 0)
}
}
}
var takeFrameAndQueue: (Queue, () -> MediaTrackFrameResult)?
var timer: SwiftSignalKit.Timer?
var polling = false
var currentRotationAngle = 0.0
var currentAspect = 1.0
public var state: (timebase: CMTimebase, requestFrames: Bool, rotationAngle: Double, aspect: Double)? {
didSet {
self.updateState()
}
}
private func updateState() {
if let (timebase, requestFrames, rotationAngle, aspect) = self.state {
if let videoLayer = self.videoLayer {
videoQueue.async {
if videoLayer.controlTimebase !== timebase || videoLayer.status == .failed {
videoLayer.flush()
videoLayer.controlTimebase = timebase
}
}
if !self.currentRotationAngle.isEqual(to: rotationAngle) || !self.currentAspect.isEqual(to: aspect) {
self.currentRotationAngle = rotationAngle
self.currentAspect = aspect
var transform = CGAffineTransform(rotationAngle: CGFloat(rotationAngle))
if !rotationAngle.isZero {
transform = transform.scaledBy(x: CGFloat(aspect), y: CGFloat(1.0 / aspect))
}
videoLayer.setAffineTransform(transform)
}
if self.videoInHierarchy {
if requestFrames {
self.startPolling()
}
}
}
}
}
private func startPolling() {
if !self.polling {
self.polling = true
self.poll(completion: { [weak self] status in
self?.polling = false
if let strongSelf = self, let (_, requestFrames, _, _) = strongSelf.state, requestFrames {
strongSelf.timer?.invalidate()
switch status {
case let .delay(delay):
strongSelf.timer = SwiftSignalKit.Timer(timeout: delay, repeat: true, completion: {
if let strongSelf = self, let videoLayer = strongSelf.videoLayer, let (_, requestFrames, _, _) = strongSelf.state, requestFrames, strongSelf.videoInHierarchy {
if videoLayer.isReadyForMoreMediaData {
strongSelf.timer?.invalidate()
strongSelf.timer = nil
strongSelf.startPolling()
}
}
}, queue: Queue.mainQueue())
strongSelf.timer?.start()
case .finished:
break
}
}
})
}
}
private func poll(completion: @escaping (PollStatus) -> Void) {
if let (takeFrameQueue, takeFrame) = self.takeFrameAndQueue, let videoLayer = self.videoLayer, let (timebase, _, _, _) = self.state {
let layerRef = Unmanaged.passRetained(videoLayer)
takeFrameQueue.async {
let status: PollStatus
do {
var numFrames = 0
let layer = layerRef.takeUnretainedValue()
let layerTime = CMTimeGetSeconds(CMTimebaseGetTime(timebase))
let rate = CMTimebaseGetRate(timebase)
var maxTakenTime = layerTime + 0.1
var finised = false
loop: while true {
let isReady = layer.isReadyForMoreMediaData
#if DEBUG
if let error = layer.error {
print("MediaPlayerNode error: \(error)")
}
#endif
if isReady {
switch takeFrame() {
case let .restoreState(frames, atTime):
layer.flush()
for i in 0 ..< frames.count {
let frame = frames[i]
let frameTime = CMTimeGetSeconds(frame.position)
maxTakenTime = frameTime
let attachments = CMSampleBufferGetSampleAttachmentsArray(frame.sampleBuffer, createIfNecessary: true)! as NSArray
let dict = attachments[0] as! NSMutableDictionary
if i == 0 {
CMSetAttachment(frame.sampleBuffer, key: kCMSampleBufferAttachmentKey_ResetDecoderBeforeDecoding as NSString, value: kCFBooleanTrue as AnyObject, attachmentMode: kCMAttachmentMode_ShouldPropagate)
CMSetAttachment(frame.sampleBuffer, key: kCMSampleBufferAttachmentKey_EndsPreviousSampleDuration as NSString, value: kCFBooleanTrue as AnyObject, attachmentMode: kCMAttachmentMode_ShouldPropagate)
}
if CMTimeCompare(frame.position, atTime) < 0 {
dict.setValue(kCFBooleanTrue as AnyObject, forKey: kCMSampleAttachmentKey_DoNotDisplay as NSString as String)
} else if CMTimeCompare(frame.position, atTime) == 0 {
dict.setValue(kCFBooleanTrue as AnyObject, forKey: kCMSampleAttachmentKey_DisplayImmediately as NSString as String)
dict.setValue(kCFBooleanTrue as AnyObject, forKey: kCMSampleBufferAttachmentKey_EndsPreviousSampleDuration as NSString as String)
//print("restore state to \(frame.position) -> \(frameTime) at \(layerTime) (\(i + 1) of \(frames.count))")
}
layer.enqueue(frame.sampleBuffer)
}
case let .frame(frame):
numFrames += 1
let frameTime = CMTimeGetSeconds(frame.position)
if rate.isZero {
//print("enqueue \(frameTime) at \(layerTime)")
}
if frame.resetDecoder {
layer.flush()
}
if frame.decoded && frameTime < layerTime {
//print("drop frame at \(frameTime) current \(layerTime)")
continue loop
}
//print("took frame at \(frameTime) current \(layerTime)")
maxTakenTime = frameTime
layer.enqueue(frame.sampleBuffer)
case .skipFrame:
break
case .noFrames:
finised = true
break loop
case .finished:
finised = true
break loop
}
} else {
break loop
}
}
if finised {
status = .finished
} else {
status = .delay(max(1.0 / 30.0, maxTakenTime - layerTime))
}
//print("took \(numFrames) frames, status \(status)")
}
DispatchQueue.main.async {
layerRef.release()
completion(status)
}
}
}
}