如何与AVMutableVideoComposition并排组合(hstack)多个视频？

import AVFoundation

// 创建AVMutableVideoComposition对象，并设置分辨率和帧速率
let videoComposition = AVMutableVideoComposition()
videoComposition.renderSize = CGSize(width: 1280, height: 720)
videoComposition.frameDuration = CMTimeMake(value: 1, timescale: 30)

// 创建AVMutableComposition对象
let composition = AVMutableComposition()

// 创建第一个AVAsset对象
guard let videoURL1 = Bundle.main.url(forResource: "video1", withExtension: "mov") else {
    return
}
let asset1 = AVAsset(url: videoURL1)
let track1 = composition.addMutableTrack(withMediaType: .video, preferredTrackID: kCMPersistentTrackID_Invalid)
try? track1?.insertTimeRange(CMTimeRangeMake(start: .zero, duration: asset1.duration), of: asset1.tracks(withMediaType: .video)[0], at: .zero)

// 创建第二个AVAsset对象
guard let videoURL2 = Bundle.main.url(forResource: "video2", withExtension: "mov") else {
    return
}
let asset2 = AVAsset(url: videoURL2)
let track2 = composition.addMutableTrack(withMediaType: .video, preferredTrackID: kCMPersistentTrackID_Invalid)
try? track2?.insertTimeRange(CMTimeRangeMake(start: .zero, duration: asset2.duration), of: asset2.tracks(withMediaType: .video)[0], at: .zero)

// 创建AVMutableVideoCompositionLayerInstruction对象，并设置变换属性
let layerInstruction1 = AVMutableVideoCompositionLayerInstruction(assetTrack: track1!)
let transform1 = CGAffineTransform(translationX: 0, y: 0)
layerInstruction1.setTransform(transform1, at: .zero)
layerInstruction1.setOpacity(1.0, at: .zero)

let layerInstruction2 = AVMutableVideoCompositionLayerInstruction(assetTrack: track2!)
let transform2 = CGAffineTransform(translationX: asset1.tracks(withMediaType: .video)[0].naturalSize.width, y: 0)
layerInstruction2.setTransform(transform2, at: .zero)
layerInstruction2.setOpacity(1.0, at: .zero)

// 创建AVMutableVideoCompositionInstruction对象，并添加AVMutableVideoCompositionLayerInstruction对象
let instruction = AVMutableVideoCompositionInstruction()
instruction.timeRange = CMTimeRangeMake(start: .zero, duration: composition.duration)
instruction.layerInstructions = [layerInstruction1, layerInstruction2]

// 将AVMutableVideoCompositionInstruction对象添加到AVMutableVideoComposition对象
videoComposition.instructions = [instruction]

// 创建AVAssetExportSession对象，并设置输出文件路径和格式
let exportSession = AVAssetExportSession(asset: composition, presetName: AVAssetExportPresetHighestQuality)
exportSession?.outputURL = outputFileURL
exportSession?.outputFileType = AVFileType.mp4
exportSession?.videoComposition = videoComposition

// 执行视频合成和导出操作
exportSession?.exportAsynchronously {
    // 处理导出完成后的操作
    if exportSession?.status == .completed {
        print("视频合成和导出成功！")
    } else if exportSession?.status == .failed {
        print("视频合成和导出失败：\(exportSession?.error?.localizedDescription ?? "")")
    } else if exportSession?.status == .cancelled {
        print("视频合成和导出被取消！")
    }
}