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• pictureBox image dispose exception

  22 octobre 2016, par Dulcia

  I recently wanted to try out AForge.NET as I found it to be quite simple, so I decided to make some simple video playback using Video.FFMPEG namespace from it, so I could put each frame directly on a pictureBox. That alone works well, but I wanted to dispose every image after not being important because it took about 1.5GB memory for no apparent reason. That’s where my problem started. For some reason, it sometimes will just throw this exception (usually when resizing the window). I’m not really sure what it could be caused by. Maybe it’s really a stupid mistake. My guess is that it could be caused by timer, but I could have done a completely different mistake and just cannot see it. This is the exception I keep getting :

      ************** Exception Text **************
  
  System.ArgumentException: Parameter is not valid.
  
     at System.Drawing.Image.get_Width()
  
     at System.Drawing.Image.get_Size()
  
     at System.Windows.Forms.PictureBox.ImageRectangleFromSizeMode(PictureBoxSizeMode mode)
  
     at System.Windows.Forms.PictureBox.OnPaint(PaintEventArgs pe)
  
     at System.Windows.Forms.Control.PaintWithErrorHandling(PaintEventArgs e, Int16 layer)
  
     at System.Windows.Forms.Control.WmPaint(Message& m)
  
     at System.Windows.Forms.Control.WndProc(Message& m)
  
     at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
  
     at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
  
     at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)

  This is the code (I do realize that public variables are not good, I’m just testing of course) :

  public long i = 0;
  
  public Bitmap img;
  
  public VideoFileReader reader;
  
  public System.Timers.Timer aTimer;
  
  
  
  public void render(object source, ElapsedEventArgs e)
  
  {
  
      if (img != null) img.Dispose();
  
      if (i < reader.FrameCount)
  
      {
  
          img = reader.ReadVideoFrame();
  
          pictureBox1.Image = img;
  
      }
  
      i++;
  
  }
  
  
  
  private void button1_Click(object sender, EventArgs e)
  
  {
  
      reader = new VideoFileReader();
  
      aTimer = new System.Timers.Timer();
  
      reader.Open("d:\\result.avi");
  
      aTimer.Elapsed += new ElapsedEventHandler(render);
  
      aTimer.Interval = reader.FrameRate;
  
      aTimer.Enabled = true;
  
  }

• varying RTP stream result from custom SIP implementation

  1er février, par Nik Hendricks

  I am in the process of creating my own SIP implementation in Node.js. As well as a b2bua as a learning project.

  


  Finding people wise in the ways of SIP has proved to be difficult elsewhere but here I have had good results

  


  this is the GitHub of my library so far node.js-sip

  


  this is the GitHub of my PBX so far FlowPBX

  


  Currently, everything is working as I expect. Although I really have some questions on possible errors in my implementation.

  


  My main issue is with RTP streams. Currently I am utilizing ffmpeg.

  


  my function goes as follows

  


  start_stream(call_id, sdp){
        console.log('Starting Stream')
        let port = sdp.match(/m=audio (\d+) RTP/)[1];
        let ip = sdp.match(/c=IN IP4 (\d+\.\d+\.\d+\.\d+)/)[1];
        let codec_ids = sdp.match(/m=audio \d+ RTP\/AVP (.+)/)[1].split(' ');
        let ffmpeg_codec_map = {
            'opus': 'libopus',
            'PCMU': 'pcm_mulaw',
            'PCMA': 'pcm_alaw',
            'telephone-event': 'pcm_mulaw',
            'speex': 'speex',
            'G722': 'g722',
            'G729': 'g729',
            'GSM': 'gsm',
            'AMR': 'amr',
            'AMR-WB': 'amr_wb',
            'iLBC': 'ilbc',
            'iSAC': 'isac',
        }

        let codecs = [];
        sdp.split('\n').forEach(line => {
            if(line.includes('a=rtpmap')){
                let codec = line.match(/a=rtpmap:(\d+) (.+)/)[2];
                let c_id = line.match(/a=rtpmap:(\d+) (.+)/)[1];
                codecs.push({                    
                    name: codec.split('/')[0],
                    rate: codec.split('/')[1],
                    channels: codec.split('/')[2] !== undefined ? codec.split('/')[2] : 1,
                    id: c_id
                })
            }
        })

        console.log('codecs')
        console.log(codecs)

        let selected_codec = codecs[0]
        if(selected_codec.name == 'telephone-event'){
            selected_codec = codecs[1]
            console.log(selected_codec)
        }

        //see if opus is available
        codecs.forEach(codec => {
            if(codec.name == 'opus'){
                selected_codec = codec;
            }
        })

        if(selected_codec.name != 'opus'){
            //check if g729 is available
            codecs.forEach(codec => {
                if(codec.name == 'G729'){
                    selected_codec = codec;
                }
            })
        }

        console.log('selected_codec')
        console.log(selected_codec)

        let spawn = require('child_process').spawn;
        let ffmpegArgs = [
            '-re',
            '-i', 'song.mp3',
            '-acodec', ffmpeg_codec_map[selected_codec.name],
            '-ar', selected_codec.rate,
            '-ac', selected_codec.channels,
            '-payload_type', selected_codec.id,
            '-f', 'rtp', `rtp://${ip}:${port}`
        ];

        let ffmpeg = spawn('ffmpeg', ffmpegArgs);

        ffmpeg.stdout.on('data', (data) => {
            console.log(`stdout: ${data}`);
        });
        ffmpeg.stderr.on('data', (data) => {
            console.error(`stderr: ${data}`);
        });




}


  


  When using zoiper to test it works great. I have seen the mobile version negotiate speex
and the desktop version negotiate opus mostly for the codec.

  


  today I tried to register a grandstream phone to my pbx and the rtp stream is blank audio.
opus is available and I have tried to prefer that in my stream but still even when selecting that I cannot get audio to the grandstream phone. This is the same case for a yealink phone. I can only get zoiper to work so far.

  


  what could be causing this behavior ? there is a clear path of communication between everything just like the zoiper client's I have used.

  


  Additionally in my sip implementation,
how important is the concept of a dialog ? currently, I just match messages by Call-ID

  


  and then choose what to send based on the method or response. is there any other underlying dialog functionality that I may need to implement ?

  


  It would just be awesome to get someone who really knows what they are talking about eyes on some of my code to direct this large codebase in the right direction but I realize that a big ask lol.

  


• How can I simply do color interpolation on this image and then save the image ? With RGBA channels as example

  24 août 2020, par karl-police

  So I got this GIF here :

  


  

  


  As you can see, it has Red, Green and Blue in it. And it also has a full transparency in it. This was composed together with FFMPEG out of images that looked exactly like that.

  


   

  


  Then, with FFMPEG I "decomposed" the RGB and Alpha channels using the filter "extractplanes".

  


  The gallery of that, in correct order starting from up to down, can be found here :

  


  https://imgur.com/a/WN0aGuW

  


  I am not sure if this actually helps me or if I'm supposed to decompose them. Because apperantly now, after decomposing them, I'm supposed to modify them, but I'm not really sure how. It's like how do I modify the red channel that only has black and white, so all at the end, will match to the specified HEX color that I want it to be to.

  


   

  


  Now, my question is. How do I exactly make the color changing happen ? Can I do this simply with JavaScript ? Is it possible to do with FFMPEG, if possible without ImageMagicks ? Maybe a programming language where not much installation is needed to do that ?

  


  What I understood is that. These channels basically contain values from 0 to 255 with black and white. I think the "brightness" is that what 0 and 255. So something inbetween, would be like grey.

  


  So basically, like we do (255,0,0) for red. In these channels, if I want red somewhere I need to put one fully white pixel on the red channel and on all the other channels, there has to be a fully black pixel.

  


  That's the concept. Now is the question, how can I do this ?

  


   

  


  At the end I want to make it look like this one as example :

  


  

  


  This is from a game. So basically that's how it looks like in the game. And the game files only use these RGBA template sprites.

  


   

  


  I asked a similar question here : How to change colors of an image using RGBA and more channels independently of their color

  


  But somehow, I might didn't seem to explain it that well.

  


   

  


  I made a thing here to test around with things. I guess that's nearly close, but the lines are kinda weird. jsfiddle.net/qsgazubk