C# MJPEG 客户端简单实现 C# MJPEG 客户端简单实现方法

//创建一个HTTP请求,只要请求不结束，MJPEG服务端会一直给请求的响应体中发送实时图片内容
HttpWebRequest hwRequest = (System.Net.HttpWebRequest)WebRequest.Create("请求URL地址");
hwRequest.Method = "GET";
HttpWebResponse hwResponse = (HttpWebResponse)hwRequest.GetResponse();
//读boundary指定的每张图片分隔符,DroidCam为:--dcmjpeg
string contentType = hwResponse.Headers["Content-Type"];
string boundryKey = "boundary=";
string boundary = contentType.Substring(contentType.IndexOf(boundryKey) + boundryKey.Length);
 
//拿到响应体流
Stream stream = hwResponse.GetResponseStream();
string headerName = "Content-Length:";
//临时存储字符串数据
StringBuilder sb = new StringBuilder();
int len = 1024;
while (true)
{
    //读取一行数据
    while (true) {
        char c = (char)stream.ReadByte();
        //Console.Write(c);
        if (c == '\n') {
            break;
        }
        sb.Append(c);
    }
    string line = sb.ToString();
    sb.Remove(0, sb.Length);
    //当前行中是否包含Content-Length:
    int i = line.IndexOf(headerName);
    if (i != -1) {
        //每张图片前有一段图片简单介绍(图片类型、长度),这里只关心长度(Content-Length:)后边的值，用于后续读取图片
        int imageFileLength = Convert.ToInt32(line.Substring(i + headerName.Length).Trim());
        //Content-Length:xxx 完后会有一个/r/n的换行符，换行符后才是真正的图片数据(不知道是DroidCam自己这样还是都这样...)
        //这里跳过/r/n
        stream.Read(new byte[2], 0, 2);
        //开始读取图片数据,imageFileLength就是读到的Content-Length:后的长度
        byte[] imageFileBytes = new byte[imageFileLength];
        stream.Read(imageFileBytes, 0, imageFileBytes.Length);
        //JPEG的文件头是: FF D8 FF ，文件尾是: FF D9，非常重要，调试时最好打印一下，便于区分读入的数据是否正好时图片的所有内容
        //Console.WriteLine("文件头:" + imageFileBytes[0].ToString("X") + " " + imageFileBytes[1].ToString("X") + " " + imageFileBytes[2].ToString("X") + " " + imageFileBytes[3].ToString("X") + " " + imageFileBytes[4].ToString("X"));
        //Console.WriteLine("文件尾:" + imageFileBytes[imageFileLength - 2].ToString("X") + " " + imageFileBytes[imageFileLength - 1].ToString("X"));
        //此处做了一个如果读入文件不全时处理,图片越大,程序循环读取速度越快，越有可能导致读取文件不全情况...，如果有好的办法解决希望前辈们指教,非常感谢!
        //文件尾是否是FF D9
        if (imageFileBytes[imageFileLength - 2].ToString("X") != "FF" && imageFileBytes[imageFileLength - 1].ToString("X") != "D9")
        {
            //读入文件内容不全，跳过次文件,让流位置跳到下次图片开始位置
            //Console.WriteLine("开始矫正...");
            char l = '0';
            while (true)
            {
                char c = (char)stream.ReadByte();
                //这里只判断了--dcmjpeg中的前两个字符--,当读到的流中连续两个字符是--时，表示流已读到下次图片开始位置
                if (l == boundary[0] && c == boundary[1])
                {
                    break;
                }
                l = c;
            }
        }
        else
        {
            //读取图片成功!
            //accessImageHandler是一个Action,用于把图片实时写到PictureBox控件中
            accessImageHandler(imageFileBytes);
        }
        //这里适当睡几十毫秒，会降低点图片读入不全情况,还未找到图片随机读取不全情况原因...
        Thread.Sleep(sleep);
    }
}
stream.Close();
hwResponse.Close();

hwRequest.Headers.Add("Authorization", "Basic " + Convert.ToBase64String(Encoding.UTF8.GetBytes(user + ":" + pass)));