我正在使用ffmpeg将var polyLineShapeLayer:CAShapeLayer?
var layerAdded = false
var path = GMSPath()
var polyLine:GMSPolyline!
// Add regular polyline to the map
func addPolyLineWithEncodedStringInMap(_ encodedString:String) {
self.polyLine = GMSPolyline(path: self.path)
polyLine.strokeWidth = 3.8
self.polyLine.strokeColor = .black
polyLine.map = googleMapView
DispatchQueue.main.asyncAfter(deadline: DispatchTime.now() + 2) {
self.addPolyLineShapeLayerToMapView()
self.layerAdded = true
}
}
// Add CAshapeLayer to map
func layer(from path: GMSPath) -> CAShapeLayer {
let breizerPath = UIBezierPath()
let firstCoordinate: CLLocationCoordinate2D = path.coordinate(at: 0)
breizerPath.move(to: self.googleMapView.projection.point(for: firstCoordinate))
for i in 1 ..< Int((path.count())){
print(path.coordinate(at: UInt(i)))
let coordinate: CLLocationCoordinate2D = path.coordinate(at: UInt(i))
breizerPath.addLine(to: self.googleMapView.projection.point(for: coordinate))
}
let shapeLayer = CAShapeLayer()
shapeLayer.path = breizerPath.cgPath
shapeLayer.strokeColor = UIColor.lightGray.withAlphaComponent(0.8).cgColor
shapeLayer.lineWidth = 4.0
shapeLayer.fillColor = UIColor.clear.cgColor
shapeLayer.lineJoin = kCALineJoinRound
shapeLayer.lineCap = kCALineCapRound
shapeLayer.cornerRadius = 5
return shapeLayer
}
func animatePath(_ layer: CAShapeLayer) {
let pathAnimation = CABasicAnimation(keyPath: "strokeEnd")
pathAnimation.duration = 2
pathAnimation.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseInEaseOut)
pathAnimation.fromValue = Int(0.0)
pathAnimation.toValue = Int(1.0)
pathAnimation.repeatCount = 200
layer.add(pathAnimation, forKey: "strokeEnd")
}
func addPolyLineShapeLayerToMapView(){
polyLineShapeLayer = self.layer(from: self.path)
if let polyLineShapeLayer = polyLineShapeLayer{
self.animatePath(polyLineShapeLayer)
self.googleMapView.layer.addSublayer(polyLineShapeLayer)
polyLineShapeLayer.zPosition = 0
}
}
// Delegate methods to control the polyline
// whenever map is about to move, if layer is already added, remove the layer from superLayer
func mapView(_ mapView: GMSMapView, willMove gesture: Bool) {
if layerAdded{
DispatchQueue.main.async {
self.polyLineShapeLayer?.removeFromSuperlayer()
self.polyLineShapeLayer = nil
}
}
}
// when map is idle again(var layerAdded:bool ensures that additional layer is not added initially when the delegate method is fired) add new instance of polylineShapeLayer to the map with current projected coordinates.
func mapView(_ mapView: GMSMapView, idleAt position: GMSCameraPosition) {
if self.layerAdded{
self.addPolyLineShapeLayerToMapView()
}
}
电影转换为mkv，就像这样：
mp4这样做，音频流将从原始DTS转换为
$ ffmpeg -i source.mkv -c:v copy -c:a aac destination.mp4
致AAC：
Stream #0:1: Audio: dts (DTS), 48000 Hz, 5.1(side), fltp, 1536 kb/s (default)
通过MacBook的内置扬声器或我的笔记本电脑收听时，口头音频（我假设将以5.1配置发送到中央声道）的声音明显向右偏移，结果文件播放得很好立体声耳机。请注意，音乐和其他声音效果似乎不会受到影响，并且保持适当的平衡。另外请注意，我已经能够使用各种源文件来重现此行为。
这是ffmpeg的横幅：
Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, 5.1, fltp, 394 kb/s (default)
答案 0 :(得分：1)
2017年11月，FFmpeg提交aacenc: support extended channel layouts using PCEs添加了对比AAC的MPEG标准所指定的更多通道布局的支持。不幸的是，它似乎已经破坏了以前可以正常使用的布局的编码。
3.4版本系列是上述提交之前的最后一个版本，如果您在使用最新版本时遇到错误，则应将其用于多通道AAC编码。
在https://trac.ffmpeg.org/ticket/7273上有一个打开的错误报告。您可以在此处发表评论以展示您的示例。