在iOS上以编程方式将flv转换为mp4

import AVFoundation

let flvURL = Bundle.main.url(forResource: "example", withExtension: "flv")!
let flvAsset = AVAsset(url: flvURL)

let mp4URL = URL(fileURLWithPath: NSTemporaryDirectory()).appendingPathComponent("example.mp4")
let exportSession = AVAssetExportSession(asset: flvAsset, presetName: AVAssetExportPresetPassthrough)
exportSession?.outputURL = mp4URL
exportSession?.outputFileType = .mp4

exportSession?.exportAsynchronously(completionHandler: {
    switch exportSession?.status {
    case .completed:
        // 转换成功
        print("FLV转换为MP4成功")
    case .failed:
        // 转换失败
        print("FLV转换为MP4失败")
    case .cancelled:
        // 转换取消
        print("FLV转换为MP4取消")
    default:
        break
    }
})