使用C#/ASP.NET MVC逐帧传输MJPEG流

Frame-by-frame MJPEG streaming with C#/ASP.NET MVC(使用C#/ASP.NET MVC逐帧传输MJPEG流)
本文介绍了使用C#/ASP.NET MVC逐帧传输MJPEG流的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!

问题描述

我一直在尝试在ASP.NET中设置MJPEG流。我想从URL检索MJEPG流,并将得到的每一帧发送到每个连接的客户端。我能够找到的示例只能从集合文件读取,而不是从URL继续流,并通过MultiStreamContent发送整个文件。因为我逐帧检索,所以不能这样做。 我想知道是否可以用ASP.NETMVC来做我想做的事情。我目前正在使用AForge video从链接检索MJPEG流。 我的控制器类代码:
using System.Net.Http;
using System.Web.Http;
using AForge.Video;

namespace VideoPrototypeMVC.Controllers
{
    public class CameraController : ApiController
    {
        int framecounter = 0;
        MJPEGStream stream = new MJPEGStream();

        [HttpGet]
        public void GetVideoContent()
        {   
            stream.Source = @"http://127.0.0.1:5002/stream";
            stream.NewFrame += new NewFrameEventHandler(showFrame);
            stream.Start();
            MultipartContent content = new MultipartContent();
            while (stream.IsRunning)
            {
            //Continues streaming should be here?
            }
        }

        //Can be used to display of a frame is available
        private void showFrame(object sender, NewFrameEventArgs eventArgs)
        {
            framecounter++;
            System.Diagnostics.Debug.WriteLine("New frame event: " + framecounter);

        }

        //Should be called at the end of the stream
        private void stopStream(object sender, ReasonToFinishPlaying reason)
        {
            System.Diagnostics.Debug.WriteLine("Stop stream");
            stream.Stop();
            framecounter = 0;
        }
    }
}

这段代码不是最终的,但我只需要让Continues流下去。我已经找到了使用Socket servers的示例,但是我还是想使用mvc,因为它可以让我更容易地设置服务器的睡觉。

推荐答案

以确保其他人也会处理此问题。我设法将@EVK(再次感谢您)说的话与我在这里找到的信息结合在一起:creating my own MJPEG stream。

注意:下面的代码只是原型/概念验证!当我运行此命令时,由于StartStream中无休止的WHILE循环,我的处理器达到了100%。我将致力于使此事件更加基于事件,但我认为下面的代码更容易解释。

using System;
using System.IO;
using System.Net;
using System.Web;
using System.Net.Http;
using System.Web.Http;
using AForge.Video;
using System.Drawing;
using System.Text;
using System.Drawing.Imaging;
using System.Threading;

namespace VideoPrototypeMVC.Controllers
{
    public class CameraController : ApiController
    {
        private MJPEGStream mjpegStream = new MJPEGStream();
        private bool frameAvailable = false;
        private Bitmap frame = null;
        private string BOUNDARY = "frame";

        /// <summary>
        /// Initializer for the MJPEGstream
        /// </summary>
        CameraController()
        {
            mjpegStream.Source = @"{{INSERT STREAM URL}}";
            mjpegStream.NewFrame += new NewFrameEventHandler(showFrameEvent);
        }

        [HttpGet]
        public HttpResponseMessage GetVideoContent()
        {   
            mjpegStream.Start();
            var response = Request.CreateResponse();
            response.Content = new PushStreamContent((Action<Stream, HttpContent, TransportContext>)StartStream);
            response.Content.Headers.ContentType = System.Net.Http.Headers.MediaTypeHeaderValue.Parse("multipart/x-mixed-replace; boundary=" + BOUNDARY);
            return response;
        }

        /// <summary>
        /// Craete an appropriate header.
        /// </summary>
        /// <param name="length"></param>
        /// <returns></returns>
        private byte[] CreateHeader(int length)
        {
            string header =
                "--" + BOUNDARY + "
" +
                "Content-Type:image/jpeg
" +
                "Content-Length:" + length + "

";

            return Encoding.ASCII.GetBytes(header);
        }

        public byte[] CreateFooter()
        {
            return Encoding.ASCII.GetBytes("
");
        }

        /// <summary>
        /// Write the given frame to the stream
        /// </summary>
        /// <param name="stream">Stream</param>
        /// <param name="frame">Bitmap format frame</param>
        private void WriteFrame(Stream stream, Bitmap frame)
        {
            // prepare image data
            byte[] imageData = null;

            // this is to make sure memory stream is disposed after using
            using (MemoryStream ms = new MemoryStream())
            {
                frame.Save(ms, ImageFormat.Jpeg);
                imageData = ms.ToArray();
            }

            // prepare header
            byte[] header = CreateHeader(imageData.Length);
            // prepare footer
            byte[] footer = CreateFooter();

            // Start writing data
            stream.Write(header, 0, header.Length);
            stream.Write(imageData, 0, imageData.Length);
            stream.Write(footer, 0, footer.Length);
        }

        /// <summary>
        /// While the MJPEGStream is running and clients are connected,
        /// continue sending frames.
        /// </summary>
        /// <param name="stream">Stream to write to.</param>
        /// <param name="httpContent">The content information</param>
        /// <param name="transportContext"></param>
        private void StartStream(Stream stream, HttpContent httpContent, TransportContext transportContext)
        {
            while (mjpegStream.IsRunning && HttpContext.Current.Response.IsClientConnected)
            {
                if (frameAvailable)
                {
                    try
                    {
                        WriteFrame(stream, frame);
                        frameAvailable = false;
                    } catch (Exception e)
                    {
                        System.Diagnostics.Debug.WriteLine(e);
                    }
                }else
                {
                    Thread.Sleep(30);
                }
            }
            stopStream();
        }

        /// <summary>
        /// This event is thrown when a new frame is detected by the MJPEGStream
        /// </summary>
        /// <param name="sender">Object that is sending the event</param>
        /// <param name="eventArgs">Data from the event, including the frame</param>
        private void showFrameEvent(object sender, NewFrameEventArgs eventArgs)
        {
            frame = new Bitmap(eventArgs.Frame);
            frameAvailable = true;
        }

        /// <summary>
        /// Stop the stream.
        /// </summary>
        private void stopStream()
        {
            System.Diagnostics.Debug.WriteLine("Stop stream");
            mjpegStream.Stop();
        }
    }
}

这篇关于使用C#/ASP.NET MVC逐帧传输MJPEG流的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持编程学习网!

本站部分内容来源互联网,如果有图片或者内容侵犯您的权益请联系我们删除!

相关文档推荐

DispatcherQueue null when trying to update Ui property in ViewModel(尝试更新ViewModel中的Ui属性时DispatcherQueue为空)
Drawing over all windows on multiple monitors(在多个监视器上绘制所有窗口)
Programmatically show the desktop(以编程方式显示桌面)
c# Generic Setlt;Tgt; implementation to access objects by type(按类型访问对象的C#泛型集实现)
InvalidOperationException When using Context Injection in ASP.Net Core(在ASP.NET核心中使用上下文注入时发生InvalidOperationException)
LINQ many-to-many relationship, how to write a correct WHERE clause?(LINQ多对多关系,如何写一个正确的WHERE子句?)