使用ios将视频录制到文件

Question

我正在尝试找一个工作样本用ios录制视频（使用xamarin），但总有一些东西丢失或者不适合我。我最好尝试使用几个论坛帖子和样本如下：

using System;

using CoreGraphics;
using Foundation;
using UIKit;
using AVFoundation;
using CoreVideo;
using CoreMedia;
using CoreFoundation;
using System.IO;
using AssetsLibrary;

namespace avcaptureframes {
    public partial class AppDelegate : UIApplicationDelegate {
        public static UIImageView ImageView;
        UIViewController vc;
        AVCaptureSession session;


        OutputRecorder outputRecorder;
        DispatchQueue queue;

        public override bool FinishedLaunching (UIApplication application, NSDictionary launchOptions)
        {
            ImageView = new UIImageView (new CGRect (10f, 10f, 200f, 200f));
            ImageView.ContentMode = UIViewContentMode.Top;

            vc = new UIViewController {
                View = ImageView
            };

            window.RootViewController = vc;

            window.MakeKeyAndVisible ();
            window.BackgroundColor = UIColor.Black;

            if (!SetupCaptureSession ())
                window.AddSubview (new UILabel (new CGRect (20f, 20f, 200f, 60f)) {
                    Text = "No input device"
                });

            return true;
        }

        bool SetupCaptureSession ()
        {
            // configure the capture session for low resolution, change this if your code
            // can cope with more data or volume
            session = new AVCaptureSession {
                SessionPreset = AVCaptureSession.PresetMedium
            };



            // create a device input and attach it to the session
            var captureDevice = AVCaptureDevice.DefaultDeviceWithMediaType (AVMediaType.Video);
            if (captureDevice == null) {
                Console.WriteLine ("No captureDevice - this won't work on the simulator, try a physical device");
                return false;
            }
            //Configure for 15 FPS. Note use of LockForConigfuration()/UnlockForConfiguration()
            NSError error = null;
            captureDevice.LockForConfiguration (out error);
            if (error != null) {
                Console.WriteLine (error);
                captureDevice.UnlockForConfiguration ();
                return false;
            }

            if (UIDevice.CurrentDevice.CheckSystemVersion (7, 0))
                captureDevice.ActiveVideoMinFrameDuration = new CMTime (1, 15);
            captureDevice.UnlockForConfiguration ();

            var input = AVCaptureDeviceInput.FromDevice (captureDevice);
            if (input == null) {
                Console.WriteLine ("No input - this won't work on the simulator, try a physical device");
                return false;
            }

            session.AddInput (input);


            // create a VideoDataOutput and add it to the sesion
            var settings = new CVPixelBufferAttributes {
                PixelFormatType = CVPixelFormatType.CV32BGRA
            };
            using (var output = new AVCaptureVideoDataOutput { WeakVideoSettings = settings.Dictionary }) {
                queue = new DispatchQueue ("myQueue");
                outputRecorder = new OutputRecorder ();
                output.SetSampleBufferDelegate (outputRecorder, queue);
                session.AddOutput (output);
            }

            session.StartRunning ();
            return true;
        }

        public override void OnActivated (UIApplication application)
        {
        }

        public class OutputRecorder : AVCaptureVideoDataOutputSampleBufferDelegate
        {
            AVAssetWriter writer=null;
            AVAssetWriterInput writerinput= null;
            CMTime lastSampleTime;
            int frame=0;
            NSUrl url;

            public OutputRecorder()
            {
                string tempFile = Path.Combine(Path.GetTempPath(), "NewVideo.mp4");
                if (File.Exists(tempFile)) File.Delete(tempFile);
                url = NSUrl.FromFilename(tempFile);
                NSError assetWriterError;
                writer = new AVAssetWriter(url, AVFileType.Mpeg4, out assetWriterError);
                var outputSettings = new AVVideoSettingsCompressed()
                {
                    Height = 300,
                    Width = 300,
                    Codec = AVVideoCodec.H264,
                    CodecSettings = new AVVideoCodecSettings
                    {
                        AverageBitRate = 1000000
                    }
                };
                writerinput = new AVAssetWriterInput(mediaType: AVMediaType.Video, outputSettings: outputSettings);
                writerinput.ExpectsMediaDataInRealTime = false;
                writer.AddInput(writerinput);
            }

            public override void DidOutputSampleBuffer (AVCaptureOutput captureOutput, CMSampleBuffer sampleBuffer, AVCaptureConnection connection)
            {
                try
                {
                    lastSampleTime = sampleBuffer.PresentationTimeStamp;

                    var image = ImageFromSampleBuffer(sampleBuffer);

                    if (frame == 0)
                    {
                        writer.StartWriting();
                        writer.StartSessionAtSourceTime(lastSampleTime);
                        frame = 1;
                    }
                    String infoString = "";
                    if (writerinput.ReadyForMoreMediaData)
                    {
                        if (!writerinput.AppendSampleBuffer(sampleBuffer))
                        {
                            infoString = "Failed to append sample buffer";
                        }
                        else
                        {
                            infoString = String.Format("{0} frames captured", frame++);
                        }
                    }
                    else
                    {
                        infoString = "Writer not ready";
                    }
                    Console.WriteLine(infoString);

                    ImageView.BeginInvokeOnMainThread(() => ImageView.Image = image);

                }
                catch (Exception e)
                {
                    Console.WriteLine(e);
                }
                finally
                {
                    sampleBuffer.Dispose();
                }
            }

            UIImage ImageFromSampleBuffer (CMSampleBuffer sampleBuffer)
            {
                // Get the CoreVideo image
                using (var pixelBuffer = sampleBuffer.GetImageBuffer () as CVPixelBuffer)
                {
                    // Lock the base address
                    pixelBuffer.Lock (CVOptionFlags.None);
                    // Get the number of bytes per row for the pixel buffer
                    var baseAddress = pixelBuffer.BaseAddress;
                    var bytesPerRow = (int)pixelBuffer.BytesPerRow;
                    var width = (int)pixelBuffer.Width;
                    var height = (int)pixelBuffer.Height;
                    var flags = CGBitmapFlags.PremultipliedFirst | CGBitmapFlags.ByteOrder32Little;
                    // Create a CGImage on the RGB colorspace from the configured parameter above
                    using (var cs = CGColorSpace.CreateDeviceRGB ())
                    {
                        using (var context = new CGBitmapContext (baseAddress, width, height, 8, bytesPerRow, cs, (CGImageAlphaInfo)flags))
                        {
                            using (CGImage cgImage = context.ToImage ())
                            {
                                pixelBuffer.Unlock (CVOptionFlags.None);
                                return UIImage.FromImage (cgImage);
                            }
                        }
                    }
                }
            }

            void TryDispose (IDisposable obj)
            {
                if (obj != null)
                    obj.Dispose ();
            }
        }
    }
}

这可以显示实时摄像头图像，我在控制台中收到“帧捕获”消息，但我找不到如何记录到文件。

我读过有关添加VideoCapture的地方，但我不知道如何链接我的代码。欢迎任何帮助。