尝试将一些视频合并在一起并将它们作为单个文件导出,从查看教程/示例看,一切似乎都是正确的但是我的AVAssetExportSession似乎永远不会完整,我的视频文件永远不会被导出,任何有关明显错误的帮助我很遗憾会非常感激.
以下是合并视频的功能
注意循环中的’视频’是一个成员变量var videos = [AVAsset](),它会在调用merge之前填充(我会检查它).
private func merge()
{
// Create AVMutableComposition to contain all AVMutableComposition tracks
var mix_composition = AVMutableComposition()
var total_time_seconds = 0.0
var tracks = [AVCompositionTrack]()
// Loop over videos and create tracks,keep incrementing total duration
for video in videos
{
// Create the composition track for this video
let track = mix_composition.addMutableTrackWithMediaType(AVMediaTypeVideo,preferredTrackID: Int32(kCMPersistentTrackID_Invalid))
// Add video duration to total time
total_time_seconds = total_time_seconds + video.duration.seconds
// Add track to array of tracks
tracks.append(track)
// Add time range to track
do
{
try track.insertTimeRange(CMTimeRangeMake(kCMTimeZero,video.duration),ofTrack: video.tracksWithMediaType(AVMediaTypeVideo)[0],atTime: video.duration)
}
catch _
{
}
}
// Set total time
let preferred_time_scale: Int32 = 600;
let total_time = CMTimeMakeWithSeconds(total_time_seconds,preferred_time_scale)
// Create main instrcution for video composition
let main_instruction = AVMutableVideoCompositionInstruction()
main_instruction.timeRange = CMTimeRangeMake(kCMTimeZero,total_time)
// Create array to hold instructions
var layer_instructions = [AVVideoCompositionLayerInstruction]()
// Ensure we have the same number of tracks as videos
if videos.count == tracks.count
{
// Loop number of videos and tracks
for var index = 0; index < videos.count; ++index
{
// Create compositioninstruction for each track
let instruction = videoCompositionInstructionForTrack(tracks[index],asset: videos[index])
if(index == 0)
{
instruction.setOpacity(0.0,atTime: videos[index].duration)
}
// Add instruction to instructions array
layer_instructions.append(instruction)
}
}
// Set tack instructions to main instruction
main_instruction.layerInstructions = layer_instructions
let main_composition = AVMutableVideoComposition()
main_composition.instructions = [main_instruction]
main_composition.frameDuration = CMTimeMake(1,30)
main_composition.renderSize = CGSize(width: UIScreen.mainScreen().bounds.width,height: UIScreen.mainScreen().bounds.height)
// Get path for Final video in the current project directory
let documents_url = NSFileManager.defaultManager().URLsForDirectory(.DocumentDirectory,inDomains: .UserDomainMask)[0]
let final_url = documents_url.URLByAppendingPathComponent("TEST.mp4")
// Create AV Export Session
let exporter = AVAssetExportSession(asset: mix_composition,presetName: AVAssetExportPresetHighestQuality)
exporter!.outputURL = final_url
exporter!.outputFileType = AVFileTypeMPEG4
exporter!.shouldOptimizeForNetworkUse = true
exporter!.videoComposition = main_composition
// Perform the Export
exporter!.exportAsynchronouslyWithCompletionHandler() {
dispatch_async(dispatch_get_main_queue(),{ () -> Void in
self.exportDidFinish(exporter!)
})
}
}
下面显示了在调用exportAsynchronouslyWithCompletionHandler时调用的exportDidFinished函数.我进入这个功能,但没有发生任何事情,因为会话状态永远不会完成.
func exportDidFinish(session: AVAssetExportSession)
{
if session.status == AVAssetExportSessionStatus.Completed
{
let outputURL = session.outputURL
let library = ALAssetsLibrary()
if library.videoAtPathIsCompatibleWithSavedPhotosAlbum(outputURL)
{
library.writeVideoAtPathToSavedPhotosAlbum(outputURL,completionBlock: { (assetURL:NSURL!,error:NSError!) -> Void in
if error != nil
{
let alert = UIAlertView(title: "Error",message: "Video Not Saved",delegate: nil,cancelButtonTitle: "OK")
alert.show()
}
else
{
let alert = UIAlertView(title: "Success",message: "Video Saved",cancelButtonTitle: "OK")
alert.show()
}
})
}
}
}
打印会话状态显示它是4失败,所以我打印session.error得到了这个,但我不确定它的含义,任何帮助都会很棒
Optional(Error Domain=AVFoundationErrorDomain Code=-11841 "Operation Stopped" UserInfo={NSLocalizedDescription=Operation Stopped,NSLocalizedFailureReason=The video could not be composed.})
解决方法
如果调用了exportDidFinish但没有任何反应,则会话的状态不是AVAssetExportSessionStatus.Completed.它可能是AVAssetExportSessionStatus.Failed或其他一些值.检查这些值,如果确实失败,请检查session.error属性以获取更多信息.
编辑：如果您想要一个又一个视频播放,请只创建一个AVMutableCompositionTrack.请参阅下面的相关更改：
...
var mix_composition = AVMutableComposition()
// Create the composition track for the videos
let track = mix_composition.addMutableTrackWithMediaType(AVMediaTypeVideo,preferredTrackID: Int32(kCMPersistentTrackID_Invalid))
//keep track of total time
var totalTime = kCMTimeZero
for video in videos
{
// Add time range to track
do
{
let videoTrack = video.tracksWithMediaType(AVMediaTypeVideo)[0]
let videoDuration = videoTrack.duration
let timeRange = CMTimeRangeMake(kCMTimeZero,videoDuration)
try track.insertTimeRange(timeRange,ofTrack: videoTrack,atTime: totalTime)
totalTime = CMTimeAdd(totalTime,videoDuration)
}
catch _
{
}
}
// Create main instruction for video composition
let main_instruction = AVMutableVideoCompositionInstruction()
main_instruction.timeRange = CMTimeRangeMake(kCMTimeZero,totalTime)
// Create array to hold instructions
var layer_instructions = [AVVideoCompositionLayerInstruction]()
// Create layer instruction
let layerInstruction = AVMutableVideoCompositionLayerInstruction(assetTrack: track)
// Add it to the array
layer_instructions.append(layerInstruction)
...
您还需要将renderSize调整为适当的值.您的视频大小可能与屏幕大小不同.
