iOS 不同尺寸、比例、方向的视频拼接播放
2018-04-11 本文已影响55人
朱亦鸣
需求是不同尺寸、比例、方向的视频拼接成一个固定尺寸的视频播放不是导出后播放是直接播放(composition）。这个需求也是让我填坑填了几天，下面先说说碰到的问题。
在这之前呢如果你知道AVMutableComposition AVMutableVideoComposition AVMutableVideoCompositionInstruction AVMutableVideoCompositionLayerInstruction 就继续往下看，不然看不懂不要怪我。
问题
- 不同视频拼接到一个视频轨道(
videoTrack)上面播放，默认会使用第一个视频的尺寸后面的视频就会去填满这个尺寸就会出现各种问题。比如说第一个视频尺寸特别小。 - 如果自定义了尺寸(
videoComposition.renderSize)那视频就不会去填满 - 解决以上的问题后填满视频后发现在同一个轨道里如果有大的视频尺寸也会出现错乱的情况
- 出现了第二个解决方案在拼接之前，先把每一个视频生成一个理想的尺寸(这也许是最笨的办法了)，但是这个办法在拼接后添加过渡动画的时候也会出现错乱的情况
于是研究了其它视频编辑类的APP也有些没有处理不同比例的情况，但是有完美处理的就是说肯定是有办法的，于是又看了一遍官方的demo发现了官方是用两个视频轨道来交替添加视频上去的，这个就解决了我们的第三个问题了，我们要做的就是处理视频的方向、比例等问题就行了。下面就上代码吧
var comVideoTracks = [AVMutableCompositionTrack]()
for _ in 0...1 {
comVideoTracks.append(muComposition.addMutableTrack(withMediaType: .video, preferredTrackID: kCMPersistentTrackID_Invalid)!)
}
var passThroughTimeRanges: [CMTimeRange] = [CMTimeRange]()
var transitionTimeRanges: [CMTimeRange] = [CMTimeRange]()
var startTime = kCMTimeZero
for (index,asset) in clips.enumerated() {
let oriVideoTrack = (asset.tracks(withMediaType: .video).first)
if oriVideoTrack == nil{
continue
}
let comVideoTrack = comVideoTracks[index % 2]
let clipRange = clipRanges[index]
try! comVideoTrack.insertTimeRange(clipRange, of: oriVideoTrack!, at: startTime)
passThroughTimeRanges.append(CMTimeRangeMake(startTime, clipRange.duration))
if index > 0 {
passThroughTimeRanges[index].start = CMTimeAdd(passThroughTimeRanges[index].start, trasitionTime)
passThroughTimeRanges[index].duration = CMTimeSubtract(passThroughTimeRanges[index].duration, trasitionTime);
}
if (index+1 < clips.count) {
passThroughTimeRanges[index].duration = CMTimeSubtract(passThroughTimeRanges[index].duration, trasitionTime);
}
startTime = CMTimeAdd(startTime, clipRange.duration)
startTime = CMTimeSubtract(startTime, trasitionTime)
if index + 1 < clips.count{
transitionTimeRanges.append(CMTimeRangeMake(startTime, trasitionTime))
}
}
我们把所有的视频交替添加到composition的两个轨道上面，passThroughTimeRanges transitionTimeRanges这两个数组里放的就是计算出来的视频过渡的时间，视频如果要加过渡动画就必须是要有重合，所以可以看到我们计算的时间是有一段重合的。我们对视频方向，比例的处理都是在AVMutableVideoCompositionLayerInstruction进行处理的
var instructions = [Any]()
for (index,asset) in clips.enumerated() {
let comVideoTrack = comVideoTracks[index % 2]
let passThroughInstruction = AVMutableVideoCompositionInstruction()
passThroughInstruction.timeRange = passThroughTimeRanges[index]
let passThroughLayer = AVMutableVideoCompositionLayerInstruction(assetTrack: comVideoTrack)
changeVideoSize(asset: asset,passThroughLayer: passThroughLayer)
passThroughInstruction.layerInstructions = [passThroughLayer]
instructions.append(passThroughInstruction)
if index + 1 < clips.count{
let transitionInstruction = AVMutableVideoCompositionInstruction()
transitionInstruction.timeRange = transitionTimeRanges[index]
let fromLayer =
AVMutableVideoCompositionLayerInstruction(assetTrack: comVideoTrack)
let toLayer =
AVMutableVideoCompositionLayerInstruction(assetTrack:comVideoTracks[1 - index % 2])
changeVideoSize(asset: asset,passThroughLayer: fromLayer)
changeVideoSize(asset: clips[index + 1],passThroughLayer: toLayer)
videoTransition(fromLayer: fromLayer,toLayer: toLayer,asset: asset, timeRange: transitionTimeRanges[index])
transitionInstruction.layerInstructions = [fromLayer, toLayer]
instructions.append(transitionInstruction)
}
}
muVideoComposition.instructions = instructions as! [AVVideoCompositionInstructionProtocol]
上面代码我们调用了changeVideoSize和videoTransition它们分别处理了视频比例方向和过渡动画
func videoTransition(fromLayer:AVMutableVideoCompositionLayerInstruction,toLayer:AVMutableVideoCompositionLayerInstruction,asset:AVAsset,timeRange:CMTimeRange) {
let oriVideoTrack = asset.tracks(withMediaType: .video).first
let natureSize = (oriVideoTrack?.naturalSize)!
switch transitionType {
case .Opacity:
fromLayer.setOpacityRamp(fromStartOpacity: 1.0, toEndOpacity: 0.0, timeRange: timeRange)
toLayer.setOpacityRamp(fromStartOpacity: 0.0, toEndOpacity: 1.0, timeRange: timeRange)
case .SwipeLeft:
fromLayer.setCropRectangleRamp(fromStartCropRectangle: CGRect.init(origin: .zero, size: videoSize), toEndCropRectangle: CGRect.init(origin: .zero, size: CGSize.init(width: 0, height: videoSize.height)), timeRange: timeRange)
default:
if degressFromVideo(asset: asset) == 90{
fromLayer.setCropRectangleRamp(fromStartCropRectangle: CGRect.init(origin: .zero, size: videoSize), toEndCropRectangle: CGRect.init(origin: .zero, size: CGSize.init(width: 0, height: videoSize.height)), timeRange: timeRange)
}else{
let width = natureSize.width > videoSize.width ? natureSize.width : videoSize.width
fromLayer.setCropRectangleRamp(fromStartCropRectangle: CGRect.init(origin: .zero, size:CGSize.init(width: width, height: videoSize.height)), toEndCropRectangle: CGRect.init(origin: .zero, size: CGSize.init(width: width, height: 0)), timeRange: timeRange)
}
}
}
暂时就做了三个过渡的动画，淡入，左扫，上扫。下面就是视频的比例问题了代码有点多
func changeVideoSize(asset:AVAsset,passThroughLayer:AVMutableVideoCompositionLayerInstruction) {
let oriVideoTrack = asset.tracks(withMediaType: .video).first
var natureSize = (oriVideoTrack?.naturalSize)!
if degressFromVideo(asset: asset) == 90 {
natureSize = CGSize.init(width: natureSize.height, height: natureSize.width)
}
//处理 livePhoto的视频
// if natureSize.width == 1440 && natureSize.height == 1080 {
// if videoRatio == .Ratio9_16{
// natureSize.width = 1308
// }else{
// natureSize.height = 980
// }
// }
//
// if natureSize.width == 1080 && natureSize.height == 1440 {
// if videoRatio == .Ratio9_16 {
// natureSize.width = 980
// }else{
// natureSize.height = 1308
// }
// }
if (Int)(natureSize.width) % 2 != 0 {
natureSize.width += 1.0
}
if videoRatio == .Ratio9_16{
if degressFromVideo(asset: asset) == 90{
let height = videoSize.width * natureSize.height / natureSize.width
let translateToCenter = CGAffineTransform.init(translationX: videoSize.width, y: videoSize.height/2 - natureSize.height/2)
let t = translateToCenter.scaledBy(x:videoSize.width/natureSize.width, y: height/natureSize.height)
let mixedTransform = t.rotated(by: .pi/2)
passThroughLayer.setTransform(mixedTransform, at: kCMTimeZero)
}else{
let height = videoSize.width * natureSize.height / natureSize.width
let translateToCenter = CGAffineTransform.init(translationX: 0, y: videoSize.height/2 - height/2)
let t = translateToCenter.scaledBy(x:videoSize.width/natureSize.width, y: height/natureSize.height)
passThroughLayer.setTransform(t, at: kCMTimeZero)
}
}else{
if degressFromVideo(asset: asset) == 90{
let width = videoSize.height * natureSize.width/natureSize.height
let translateToCenter = CGAffineTransform.init(translationX: videoSize.width/2 + width/2, y: 0)
let t = translateToCenter.scaledBy(x:width/natureSize.width, y: videoSize.height/natureSize.height)
let mixedTransform = t.rotated(by: .pi/2)
passThroughLayer.setTransform(mixedTransform, at: kCMTimeZero)
}else{
let width = videoSize.height * natureSize.width/natureSize.height
let translateToCenter = CGAffineTransform.init(translationX: videoSize.width/2 - width/2, y: 0)
let t = translateToCenter.scaledBy(x:width/natureSize.width, y: videoSize.height/natureSize.height)
passThroughLayer.setTransform(t, at: kCMTimeZero)
}
}
}
我根据了16:9和9:16两种比例来判断，其它比例可按照这种方法来判断。我注释掉的是livephoto里的视频处理，这个也是比较坑的地方，也许只有碰到的人才能体会到了。碰到这种问题的人应该也都是做视频编辑类项目的人。最后就是播放
let playItem = AVPlayerItem.init(asset: editor.compostion)
playItem.videoComposition = editor.videoComposition
player = AVPlayer.init(playerItem: playItem)
就到这了，大家碰到了什么稀奇古怪的问题可以来交流交流。代码地址
