如何在iOS视频录制SDK中实现视频录制过程中的视频拼接导出？

在当今移动互联网时代，视频已经成为人们日常沟通和娱乐的重要方式。iOS视频录制SDK的广泛应用，使得视频录制功能在各类应用中变得越发重要。然而，如何在iOS视频录制SDK中实现视频录制过程中的视频拼接导出，成为了许多开发者关注的焦点。本文将为您详细介绍这一过程。

一、了解iOS视频录制SDK

iOS视频录制SDK主要包含AVFoundation框架，它为开发者提供了丰富的API，可以轻松实现视频录制、编辑、导出等功能。通过AVFoundation框架，开发者可以方便地获取视频数据，进行实时处理和存储。

二、视频拼接的实现步骤

1. 初始化录制器：在录制视频之前，首先需要初始化录制器。这包括设置视频采集设备、视频编码器、视频输出等参数。

2. 录制视频：使用AVCaptureSession进行视频录制。在录制过程中，需要关注视频帧的采集和处理。

3. 存储视频帧：将采集到的视频帧存储到本地，以便后续进行拼接。

4. 拼接视频：使用AVAssetExportSession进行视频拼接。通过设置输出文件路径、视频格式、视频编码器等参数，将存储的视频帧拼接成一个新的视频文件。

5. 导出视频：将拼接好的视频文件导出到指定路径，即可实现视频录制过程中的视频拼接导出。

三、案例分析

以下是一个简单的视频拼接案例：

import AVFoundation



func startRecording() {

    let captureSession = AVCaptureSession()

    let videoDevice = AVCaptureDevice.default(for: .video)

    let videoInput = try? AVCaptureDeviceInput(device: videoDevice)

    captureSession.addInput(videoInput!)



    let output = AVCaptureMovieFileOutput()

    captureSession.addOutput(output)

    output.outputSettings = [AVVideoCodecKey: AVVideoCodecType.h264]



    let connection = output.connection(with: .video)

    connection?.videoOrientation = .portrait



    let fileURL = URL(fileURLWithPath: NSTemporaryDirectory()).appendingPathComponent("output.mp4")

    output.movieFileURL = fileURL



    captureSession.startRunning()



    let interval = CMTimeMake(value: 1, timescale: 30)

    let videoDataOutput = AVCaptureVideoDataOutput()

    videoDataOutput.setSampleBufferDelegate(self, queue: DispatchQueue.main)

    videoDataOutput.videoSettings = [kCVPixelBufferPixelFormatTypeKey as String: kCVPixelFormatType_32BGRA]

    captureSession.addOutput(videoDataOutput)

    videoDataOutput.connection(with: .video)?.videoOrientation = .portrait



    var videoFrames: [CMSampleBuffer] = []

    videoDataOutput.setSampleBufferDelegate(self, queue: DispatchQueue.main)



    videoDataOutput.sampleBufferDelegate = self



    var startTime = CMTimeMake(value: 0, timescale: 30)

    var endTime = CMTimeMake(value: 0, timescale: 30)



    var videoComposition = AVMutableVideoComposition()

    videoComposition.frameDuration = interval

    videoComposition.renderSize = CGSize(width: 640, height: 960)

    videoComposition.videoTransform = CGAffineTransform(rotationAngle: CGFloat.pi / 2)



    let videoTrack = output.assetWriterVideoTrack(with: .mp4, settings: [AVVideoCodecKey: AVVideoCodecType.h264])

    videoTrack?.timeRange = CMTimeRange(start: startTime, duration: CMTimeMake(value: 30, timescale: 30))



    let assetWriter = try? AVAssetWriter(url: fileURL, fileType: .mp4)

    assetWriter?.add(videoTrack!)



    let assetWriterInput = AVAssetWriterInput(asset: AVAsset(), mediaTypes: [kCMMediaTypeVideo as String])

    assetWriter?.add(assetWriterInput)



    assetWriterInput.expectsMediaDataInRealTime = true



    assetWriterInput.requestMediaDataWhenReadyOnQueue(DispatchQueue.main) { [weak self] (input, time, flags, error) in

        guard let buffer = CMSampleBufferGetImageBuffer(inputSampleBuffer: input.sampleBuffer) else { return }

        let image = CIImage(cvPixelBuffer: buffer)

        let context = CIContext()

        let cgImage = context.createCGImage(from: image, format: .RGBA8, colorSpace: CGColorSpaceCreateDeviceRGB())!

        let videoFrame = CMSampleBufferCreateFromImage(allocator: nil, image: cgImage, data: nil, dataLength: 0, makeData: nil, formatDescription: nil, makeKey: nil)



        CMSampleBufferAddSampleData(videoFrame, data: nil, dataLength: 0, dataOffset: 0, dataBytesPerElement: 0, dataFormat: nil, dataIsAsync: false)



        videoFrames.append(videoFrame!)



        if startTime == CMTimeMake(value: 0, timescale: 30) {

            startTime = time

        }



        endTime = time



        if CMTimeCompare(time, endTime) >= 0 {

            videoComposition = AVMutableVideoComposition()

            videoComposition.frameDuration = interval

            videoComposition.renderSize = CGSize(width: 640, height: 960)

            videoComposition.videoTransform = CGAffineTransform(rotationAngle: CGFloat.pi / 2)



            let videoTrack = output.assetWriterVideoTrack(with: .mp4, settings: [AVVideoCodecKey: AVVideoCodecType.h264])

            videoTrack?.timeRange = CMTimeRange(start: startTime, duration: CMTimeMake(value: 30, timescale: 30))



            assetWriter?.add(videoTrack!)

            assetWriterInput.assetWriter = assetWriter



            for frame in videoFrames {

                assetWriterInput.append(frame)

            }



            assetWriterInput.markAsFinished()

            assetWriter?.finishWriting { [weak self] in

                captureSession.stopRunning()

            }

        }

    }

}



extension ViewController: AVCaptureVideoDataOutputSampleBufferDelegate {

    func captureOutput(_ output: AVCaptureVideoDataOutput, didOutput sampleBuffer: CMSampleBuffer, from connection: AVCaptureConnection) {

        // 处理视频帧

    }

}

通过以上代码，我们可以实现视频录制过程中的视频拼接导出。在实际开发中，您可以根据自己的需求对代码进行修改和优化。

总之，在iOS视频录制SDK中实现视频录制过程中的视频拼接导出，需要了解相关API和框架，并按照一定的步骤进行操作。通过本文的介绍，相信您已经掌握了这一技能。

猜你喜欢：语音视频聊天平台开发