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• ffmpeg record timelapse camera v4l2

  21 mars 2019, par Paul G.

  How can I instruct ffmpeg (v. : 3.4.5) to record only one frame per minute from my video camera at /dev/video0 and copy it to a new file with 30 frames per second ? Goal is timelapse video of some months and record only one frame per minute into the out video to save space and processing power instead of just capturing the camera at 30fps and then preprocess the huge video file for speed up...

  The camera delivers a 1920x1080 30fps stream with "mjpeg" selected in commandline. I would like to keep the raw frames and just copy them into the out file. I tried this command to get 1fps input to 30fps output but this seems not to work :

  ffmpeg -framerate 1 -input_format mjpeg -i /dev/video0 -r 30 -c:v copy -an out.mp4
  
  
  
  [video4linux2,v4l2 @ 0x55ece63ac360] The driver changed the time per frame from 1/1 to 1/30
  
  Input #0, video4linux2,v4l2, from '/dev/video0':
  
    Duration: N/A, start: 37064.594605, bitrate: N/A
  
      Stream #0:0: Video: mjpeg, yuvj422p(pc, bt470bg/unknown/unknown), 1920x1080, 30 fps, 30 tbr, 1000k tbn, 1000k tbc

  But this doesnt work.

• Can't record full screen using FFMEG Video File Writer - C#

  2 avril 2019, par nsds

  My app need to record entire screen as video. For that I have installed

  AForge.Video.FFMPEG

  and did like below. Now I can record the screen. But some bottom area and right end area of screen is missing. Can anyone suggest what causes the issue ? I want to record the entire screen.

  SystemInformation.VirtualScreen

  is used to calculate screen size. it is getting as 1536*864

    private ScreenCaptureStream _streamVideo;
  
    private VideoFileWriter _Screenwriter;
  
    private Rectangle _screenArea;
  
    private bool _isScreenRecording;
  
    private int _Screenwidth;
  
    private int _Screenheight;
  
    public RecordVideo()
  
      {
  
          InitializeComponent(); 
  
          this._Screenwriter = new VideoFileWriter();
  
          this._Screenwidth = SystemInformation.VirtualScreen.Width;
  
          this._Screenheight = SystemInformation.VirtualScreen.Height;
  
          this._isScreenRecording = false;
  
          this._screenArea = Rectangle.Empty;
  
        }
  
   private void btn_startRecord_Click(object sender, EventArgs e)
  
      {
  
          try
  
          {        
  
          if (btn_screenRecord.Text == "Record")
  
          {
  
              FolderBrowserDialog fbd = new FolderBrowserDialog();
  
              if (fbd.ShowDialog() == DialogResult.OK)
  
              {
  
                  _isScreenRecording = true;
  
                  this.StartRecScreen(fbd.SelectedPath);
  
              }
  
          }
  
          else
  
          {
  
              _isScreenRecording = false;
  
              btn_screenRecord.Text = "Record";
  
              MessageBox.Show(@"Recorded !");
  
          }
  
          }
  
          catch (Exception EX)
  
          { MessageBox.Show(EX.Message); }
  
      }
  
  
  
  private void StartRecScreen(string path)
  
      {
  
         btn_screenRecord.Text = "Stop";
  
         this.SetScreenArea();
  
        _isRecording = true;
  
         string fullName = string.Format(@"{0}\{1}_{2}.mp4", path, "Record_", DateTime.Now.ToString("d_MMM_yyyy_HH_mm_ssff"));
  
  
  
              // Save File option
  
              _Screenwriter.Open(
  
                  fullName,
  
                  this._Screenwidth,
  
                  this._Screenheight,
  
                  10, VideoCodec.MPEG4, 1000000);
  
              // create screen capture video source
  
              this._streamVideo = new ScreenCaptureStream(this._screenArea);
  
  
  
              // set NewFrame event handler
  
              this._streamVideo.NewFrame += new NewFrameEventHandler(this.video_NewScreenFrame);
  
  
  
              // start the video source
  
              this._streamVideo.Start();
  
  
  
      }
  
      private void video_NewScreenFrame(object sender, NewFrameEventArgs eventArgs)
  
      {
  
          if (this._isScreenRecording)
  
          {              
  
              this._Screenwriter.WriteVideoFrame(eventArgs.Frame);             
  
          }
  
          else
  
          {             
  
              _streamVideo.SignalToStop();             
  
              _Screenwriter.Close();
  
          }
  
      }
  
  
  
      private void SetScreenArea()
  
      {
  
          // get entire desktop area size
  
          foreach (Screen screen in Screen.AllScreens)
  
          {
  
              this._screenArea = Rectangle.Union(_screenArea, screen.Bounds);
  
          }
  
      }

• How to record sound/audio via FFmpeg, Alsa, PulseAudio or Sox without a soundcard (using the commandline)

  13 avril 2019, par Heart Of A Lion

  I’m trying to record audio on an Ubuntu server that has no soundcard or any other audio device. When I use the following Alsa command to list any audio devices, then it can’t find any devices.

  arecord -l

  I’ve tried recording/capturing audio using the following packages, but because there is no soundcard they all fail to record any audio :

  ffmpeg, alsa, pulseaudio, sox

  Now it should be possible to record sound on a server that has no soundcard, as some people have managed to do it. The question is how.

  Can someone give a step by step commandline walk-through of how to do this on an Ubuntu server, so that audio can be recorded on the server using any of the above-mentioned packages ?