How to better implement start and stop video recording Web Services using Axis Media Parser API?

Question

I have a C# Web Service which records data from an IP camera. This service works fine when I record data during a specified amount of time, for example 10 seconds. But my objective is to achieve data recording for an unspecified amount of time and let the user press to stop recording. So I modified my code creating a new Web Service (stopRecording) to change the value of a global variable that acts as a mutex. Obviously this is wrong because I test it but I don´t know how to proceed. Can anybody help me? I would really appreciate it.

Down here I leave the relevant code.

    [WebMethod]
    public string startRecording(string ipAddress)
    {

        // Connection preset for H.264 (HTTP API 3.0)
        string Url = "axrtsp:://" + ipAddress + "/axis-media/media.amp?videocodec=h264";            
        string UserName = "username";
        string Password = "pass";

        string Path = "C:/directory/subdirectory/";
        string Filename = "myRecordedFile.bin";

        string FilePath = Path + Filename;
        // Open binary output file to write parsed video frames into
        using (FileStream outFileStream = new FileStream(FilePath, FileMode.Create))            

        using (outFile = new BinaryWriter(outFileStream))
        {

            try
            {

                // Register for events like OnVideoSample, OnAudioSample, OnTriggerData and OnError
                ...

                // Set connection and media properties
                ...

                // Get absolute time from Axis device
                ...

                // Connect to the device                   
                int cookieID;
                int numberOfStreams;
                object buffer;
                parser.Connect(out cookieID, out numberOfStreams, out buffer);

                // Write media type information to out file (buffer is an array of bytes)
                byte[] mediaTypeBuffer = (byte[])buffer;
                outFile.Write(mediaTypeBuffer.Length);
                outFile.Write(mediaTypeBuffer, 0, mediaTypeBuffer.Length);

                // Start the media stream and registered event handlers will be called
                parser.Start();
                Debug.WriteLine("Will start recording...");  
                do {

                    Debug.WriteLine("recording...");         //want to record during an unspecified time               

                } while (record); //my mutex variable that doesn´t make the thing even when I call the stopRecording Web Service. The program remains overlooping

                System.Diagnostics.Debug.Write("Finish recording... never reached!!!!! ");  
                // Stop the stream
                parser.Stop();

                // Unregister event handlers
                ...
            }
            catch (COMException e)
            {
                Console.WriteLine("Exception for {0}, {1}", parser.MediaURL, e.Message);
            }
            // Inform the GC that COM object no longer will be used
            Marshal.FinalReleaseComObject(parser);
            parser = null;
            Console.WriteLine("Stream stopped");
        }

        return "Recording from camera " + Url;
    }

    [WebMethod]
    public string stopRecording()
    {
        System.Diagnostics.Debug.Write("I want to stop recording..."); 
        record = false;

        return "Stop";
    }

Answer 1

Your record variable is not a Mutex object, but a simple flag... Which is besides the point.

Trouble here is that you code in startRecording() never gives the hand back to the parent class and might be holding the processing thread forever.

If I might suggest, why not create a thread to do your recording ? You have a number of possibilities here ( new Thread(), Action.BeginInvoke(), .. )

This way, you give a chance to your stopRecording to be received and set this record flag to false and leave the recording thread.