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• Video duration not detected by moviepy

  27 août 2023, par Kyv

  I have downloaded a video online, and wanted to add a background sound to it.
I followed this link :
Combining an audio file with video file in python
But, while reading the file

  


  my_clip = mpe.VideoFileClip('file.mp4')


  


  I get the error [mov,mp4,m4a,3gp,3g2,mj2 @ 00000152769e78c0] moov atom not found : path/to/file.mp4 Invalid data found when processing input from line 320 in the github resource https://github.com/victorcampos7/tensorflow-ffmpeg/blob/master/ffmpeg_reader.py
How to overcome this issue ?
  
The video I am testing on : https://simgool.com/salon/SHY4xAqxVZ

  


• VLC - Transcoding a 4k Picture to a Transport Stream

  20 janvier 2020, par gdogg371

  After a lot of crying, stamping my feet and pulling my hair out, I have now managed to transcode my 4k capture card into an RTP MPEG2 transport stream using VLC, as per the below :

  vlc dshow:// :dshow-vdev="Video (00 Pro Capture HDMI 4K+)" :dshow-adev="Audio (2- 00 Pro Capture HDMI 4K+)" :dshow-threads=8 :dshow-aspect-ratio=16\:9 :dshow-size="2160x1080" :dshow-pixel_format=NV12 :dshow-tune=film :dshow-preset=veryslow :dshow-vcodec=hevc_nvenc :dshow-fps=50 :dshow-crf=0 :dshow-acodec=mp4a :dshow-stereo-mode=5 :dshow-force-surround-sound=0 :dshow-ab=128 :dshow-samplerate=44100 :no-dshow-config :live-caching=100 :sout=#transcode{venc=ffmpeg,vcodec=mp2v,threads=8,aspect=16:9,width=2160,height=1080,fps=50,aenc=ffmpeg,acodec=a52,ab=1500,channels=6,samplerate=48000,soverlay}:rtp{dst=192.168.1.15,port=8554,mux=ts}

  My remaining issue though is, that I cannot get a 4k picture to transcode cleanly. I get horrendous stutter of the picture if I try and 2160x1080 at 50 fps is the best I have been able to achieve.

  The Magewell 4k card I have been using runs natively at 3840x2160 at 50fps, outputting a raw video signal. Is there some kind of built in limitation of MPEG2 where it cannot handle a 4k signal that I am not aware of ?

  Can anyone suggests some amendments to the above, so as to process a 4k signal properly ?

  Thanks

• .NET Process - Redirect stdin and stdout without causing deadlock

  21 juillet 2017, par user1150856

  I’m trying to encode a video file with FFmpeg from frames generated by my program and then redirect the output of FFmpeg back to my program to avoid having an intermediate video file.

  However, I’ve run into what seems to be a rather common problem when redirecting outputs in System.Diagnostic.Process, mentioned in the remarks of the documentation here, which is that it causes a deadlock if run synchronously.

  After tearing my hair out over this for a day, and trying several proposed solutions found online, I still cannot find a way to make it work. I get some data out, but the process always freezes before it finishes.

  ---

  Here is a code snippet that produces said problem :

  static void Main(string[] args)
  
      {
  
  
  
          Process proc = new Process();
  
  
  
          proc.StartInfo.FileName = @"ffmpeg.exe";
  
          proc.StartInfo.Arguments = String.Format("-f rawvideo -vcodec rawvideo -s {0}x{1} -pix_fmt rgb24 -r {2} -i - -an -codec:v libx264 -preset veryfast -f mp4 -movflags frag_keyframe+empty_moov -",
  
              16, 9, 30);
  
          proc.StartInfo.UseShellExecute = false;
  
          proc.StartInfo.RedirectStandardInput = true;
  
          proc.StartInfo.RedirectStandardOutput = true;
  
  
  
          FileStream fs = new FileStream(@"out.mp4", FileMode.Create, FileAccess.Write);
  
  
  
          //read output asynchronously
  
          using (AutoResetEvent outputWaitHandle = new AutoResetEvent(false))
  
          {
  
              proc.OutputDataReceived += (sender, e) =>
  
              {
  
                  if (e.Data == null)
  
                  {
  
                      outputWaitHandle.Set();
  
                  }
  
                  else
  
                  {
  
                      string str = e.Data;
  
                      byte[] bytes = new byte[str.Length * sizeof(char)];
  
                      System.Buffer.BlockCopy(str.ToCharArray(), 0, bytes, 0, bytes.Length);
  
                      fs.Write(bytes, 0, bytes.Length);
  
                  }
  
              };
  
          }
  
  
  
  
  
          proc.Start();
  
          proc.BeginOutputReadLine();
  
  
  
          //Generate frames and write to stdin
  
          for (int i = 0; i < 30*60*60; i++)
  
          {
  
              byte[] myArray = Enumerable.Repeat((byte)Math.Min(i,255), 9*16*3).ToArray();
  
              proc.StandardInput.BaseStream.Write(myArray, 0, myArray.Length);
  
          }
  
  
  
          proc.WaitForExit();
  
          fs.Close();
  
          Console.WriteLine("Done!");
  
          Console.ReadKey();
  
  
  
      }

  Currently i’m trying to write the output to a file anyway for debugging purposes, but this is not how the data will eventually be used.

  If anyone knows a solution it would be very much appreciated.