Merge videos & images in AVMutableComposition using AVMutableCompositionTrack, not AVVideoCompositionCoreAnimationTool?

问题

The code below exports a video using AVMutableComposition. But in the exported video, if you want an image to display for 3 seconds after the source video finishes, is there a way to do that with AVMutableCompositionTrack or do you need to add an image layer and animate its appearance after the video ends?

Eventually, the goal is to merge an arbitrary number of images and videos into one master video.

Unfortunately, during testing it seems like AVVideoCompositionCoreAnimationTool severely slows down the export process (from < 1 second to 10-20 seconds), so the goal is to avoid AVVideoCompositionCoreAnimationTool if possible.

    // Create composition object
    let composition = AVMutableComposition()
    let compositionVideoTrack = composition.addMutableTrackWithMediaType(AVMediaTypeVideo, preferredTrackID: CMPersistentTrackID(kCMPersistentTrackID_Invalid))
    let compositionAudioTrack = composition.addMutableTrackWithMediaType(AVMediaTypeAudio, preferredTrackID: CMPersistentTrackID(kCMPersistentTrackID_Invalid))
    var insertTime = kCMTimeZero

    // Extract tracks from slice video
    let videoURL = NSURL(fileURLWithPath: videoPath)
    let videoAsset = AVURLAsset(URL: videoURL, options: nil)
    let sourceVideoTrack = videoAsset.tracksWithMediaType(AVMediaTypeVideo)[0]
    let sourceAudioTrack = videoAsset.tracksWithMediaType(AVMediaTypeAudio)[0]
    do {
        try compositionVideoTrack.insertTimeRange(CMTimeRangeMake(kCMTimeZero, videoAsset.duration), ofTrack: sourceVideoTrack, atTime: kCMTimeZero)
        try compositionAudioTrack.insertTimeRange(CMTimeRangeMake(kCMTimeZero, videoAsset.duration), ofTrack: sourceAudioTrack, atTime: kCMTimeZero)
    } catch {
        print("Error with insertTimeRange while exporting video: \(error)")
    }

    // Export composition to video
    let outputURL = getFilePath(getUniqueFilename(gMP4File))
    let exporter = AVAssetExportSession(asset: composition, presetName: AVAssetExportPresetHighestQuality)
    exporter!.outputURL = NSURL(fileURLWithPath: outputURL)
    exporter!.outputFileType = AVFileTypeMPEG4
    exporter!.exportAsynchronouslyWithCompletionHandler({
        self.exportDidFinish(exporter!)
    })

回答1:

After consulting others on SO and performing more web research, it seems like this is not possible. Merging an image with a video into a master video that is playable out of an app seems to require AVVideoCompositionCoreAnimationTool.

来源：https://stackoverflow.com/questions/34937862/merge-videos-images-in-avmutablecomposition-using-avmutablecompositiontrack-n