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Browsing javaCamViewer/VideoSource/JPEGStream.cs (6.92 KB)
// Motion Detector
//
// Copyright � Andrew Kirillov, 2005
// andrew.kirillov@gmail.com
//
namespace VideoSource
{
using System;
using System.Drawing;
using System.IO;
using System.Threading;
using System.Net;
/// <summary>
/// JPEGSource - JPEG downloader
/// </summary>
public class JPEGStream : IVideoSource
{
private string source;
private string login = null;
private string password = null;
private object userData = null;
private int framesReceived;
private int bytesReceived;
private bool useSeparateConnectionGroup = false;
private bool preventCaching = false;
private int frameInterval = 0; // frame interval in miliseconds
private const int bufSize = 512 * 1024; // buffer size
private const int readSize = 1024; // portion size to read
private Thread thread = null;
private ManualResetEvent stopEvent = null;
// new frame event
public event CameraEventHandler NewFrame;
// SeparateConnectioGroup property
// indicates to open WebRequest in separate connection group
public bool SeparateConnectionGroup
{
get { return useSeparateConnectionGroup; }
set { useSeparateConnectionGroup = value; }
}
// PreventCaching property
// If the property is set to true, we are trying to prevent caching
// appneding fake parameter to URL. It's needed is client is behind
// proxy server.
public bool PreventCaching
{
get { return preventCaching; }
set { preventCaching = value; }
}
// FrameInterval property - interval between frames
// If the property is set 100, than the source will produce 10 frames
// per second if it possible
public int FrameInterval
{
get { return frameInterval; }
set { frameInterval = value; }
}
// VideoSource property
public virtual string VideoSource
{
get { return source; }
set { source = value; }
}
// Login property
public string Login
{
get { return login; }
set { login = value; }
}
// Password property
public string Password
{
get { return password; }
set { password = value; }
}
// FramesReceived property
public int FramesReceived
{
get
{
int frames = framesReceived;
framesReceived = 0;
return frames;
}
}
// BytesReceived property
public int BytesReceived
{
get
{
int bytes = bytesReceived;
bytesReceived = 0;
return bytes;
}
}
// UserData property
public object UserData
{
get { return userData; }
set { userData = value; }
}
// Get state of the video source thread
public bool Running
{
get
{
if (thread != null)
{
if (thread.Join(0) == false)
return true;
// the thread is not running, so free resources
Free();
}
return false;
}
}
// Constructor
public JPEGStream()
{
}
// Start work
public void Start()
{
if (thread == null)
{
framesReceived = 0;
bytesReceived = 0;
// create events
stopEvent = new ManualResetEvent(false);
// create and start new thread
thread = new Thread(new ThreadStart(WorkerThread));
thread.Name = source;
thread.Start();
}
}
// Signal thread to stop work
public void SignalToStop()
{
// stop thread
if (thread != null)
{
// signal to stop
stopEvent.Set();
}
}
// Wait for thread stop
public void WaitForStop()
{
if (thread != null)
{
// wait for thread stop
thread.Join();
Free();
}
}
// Abort thread
public void Stop()
{
if (this.Running)
{
thread.Abort();
WaitForStop();
}
}
// Free resources
private void Free()
{
thread = null;
// release events
stopEvent.Close();
stopEvent = null;
}
// Thread entry point
public void WorkerThread()
{
byte[] buffer = new byte[bufSize]; // buffer to read stream
HttpWebRequest req = null;
WebResponse resp = null;
Stream stream = null;
Random rnd = new Random((int) DateTime.Now.Ticks);
DateTime start;
TimeSpan span;
while (true)
{
int read, total = 0;
try
{
start = DateTime.Now;
// create request
if (!preventCaching)
{
req = (HttpWebRequest) WebRequest.Create(source);
}
else
{
req = (HttpWebRequest) WebRequest.Create(source + ((source.IndexOf('?') == -1) ? '?' : '&') + "fake=" + rnd.Next().ToString());
}
// set login and password
if ((login != null) && (password != null) && (login != ""))
req.Credentials = new NetworkCredential(login, password);
// set connection group name
if (useSeparateConnectionGroup)
req.ConnectionGroupName = GetHashCode().ToString();
// get response
resp = req.GetResponse();
// get response stream
stream = resp.GetResponseStream();
// loop
while (!stopEvent.WaitOne(0, true))
{
// check total read
if (total > bufSize - readSize)
{
System.Diagnostics.Debug.WriteLine("flushing");
total = 0;
}
// read next portion from stream
if ((read = stream.Read(buffer, total, readSize)) == 0)
break;
total += read;
// increment received bytes counter
bytesReceived += read;
}
if (!stopEvent.WaitOne(0, true))
{
// increment frames counter
framesReceived++;
// image at stop
if (NewFrame != null)
{
Bitmap bmp = (Bitmap) Bitmap.FromStream(new MemoryStream(buffer, 0, total));
// notify client
NewFrame(this, new CameraEventArgs(bmp));
// release the image
bmp.Dispose();
bmp = null;
}
}
// wait for a while ?
if (frameInterval > 0)
{
// times span
span = DateTime.Now.Subtract(start);
// miliseconds to sleep
int msec = frameInterval - (int) span.TotalMilliseconds;
while ((msec > 0) && (stopEvent.WaitOne(0, true) == false))
{
// sleeping ...
Thread.Sleep((msec < 100) ? msec : 100);
msec -= 100;
}
}
}
catch (WebException ex)
{
System.Diagnostics.Debug.WriteLine("=============: " + ex.Message);
// wait for a while before the next try
Thread.Sleep(250);
}
catch (Exception ex)
{
System.Diagnostics.Debug.WriteLine("=============: " + ex.Message);
}
finally
{
// abort request
if (req != null)
{
req.Abort();
req = null;
}
// close response stream
if (stream != null)
{
stream.Close();
stream = null;
}
// close response
if (resp != null)
{
resp.Close();
resp = null;
}
}
// need to stop ?
if (stopEvent.WaitOne(0, true))
break;
}
}
}
}
Download javaCamViewer/VideoSource/JPEGStream.cs