Swift将视频NSData写入图库

import AVFoundation

guard let documentsDirectory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first else { return }
let videoOutputURL = documentsDirectory.appendingPathComponent("video.mp4")

guard let assetWriter = try? AVAssetWriter(outputURL: videoOutputURL, fileType: .mp4) else { return }

let videoSettings = [
    AVVideoCodecKey: AVVideoCodecType.h264,
    AVVideoWidthKey: 640,
    AVVideoHeightKey: 480
] as [String : Any]

let videoInput = AVAssetWriterInput(mediaType: .video, outputSettings: videoSettings)
videoInput.expectsMediaDataInRealTime = true

guard assetWriter.canAdd(videoInput) else { return }
assetWriter.add(videoInput)

let videoData: NSData = ... // 视频的NSData数据

videoInput.requestMediaDataWhenReady(on: DispatchQueue.global(qos: .default)) {
    while videoInput.isReadyForMoreMediaData {
        let sampleBuffer = self.createSampleBuffer(from: videoData) // 创建一个包含视频数据的CMSampleBuffer对象
        if videoInput.append(sampleBuffer) == false {
            break
        }
    }
}

videoInput.markAsFinished()
assetWriter.finishWriting {
    if assetWriter.status == .completed {
        // 写入成功，保存到图库
        PHPhotoLibrary.shared().performChanges({
            PHAssetChangeRequest.creationRequestForAssetFromVideo(atFileURL: videoOutputURL)
        }) { success, error in
            if success {
                // 保存成功
            } else {
                // 保存失败
            }
        }
    } else {
        // 写入失败
    }
}