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• Recording with python librtmp RTMP shrinks

  31 décembre 2022, par Yojuan

  The code for capturing a video stream using python librtmp is this :

  


  import librtmp

conn = librtmp.RTMP('rtmp://some_program', live=True)
conn.connect()
stream = conn.create_stream(update_buffer=True)
        
f = open("my_program.flv", 'wb')
while True:
    try:
        data=stream.read(1024)
        if data:
            f.write(data)
            f.flush()
    except:
        print("Error during stream")


  


  The duration of the program is of 1 hour, but when i play the video, the duration becomes in 59 min and 52 secs or 59 min and 56 secs.... but in the most cases the duration is 1 hour exactly.

  


  I noticed that the first record always is perfect but in some cases the second shrinks (when I use the function for second time or more)

  


  First I thought the problem was on ffmpeg because I use it to encode the video but it isn't because the video without encoding (the raw capture) shrinks anyway and i have other program that capture the same video with duration of 1 hour every time.

  


  What happens here ? I suppose that there is a buffer that is not being emptied correctly or something like that.

  


• ffmpeg.exe freezes

  31 octobre 2017, par Ayhan Dorman

  I’m using Asp.Net C# Framework 4 and currently developing a video conversion application. I’m also using ffmpeg to convert from all uploaded formats to flv. I’m first converting uploaded file to mpg and after to flv due to problems I encountered while trying conversion directly to flv from mp4 sometimes. But ffmpeg freezes as soon as it’s done with conversion process to mpg file. When I run task manager and check the processes list, it just stands there using no CPU resource. When I end the ffmpeg process directly from task manager, other process take place which converts from mpg to flv and preview file (jpg) and works smoothly. Due to freezing of first process, the second process cannot start when I try to upload from my web page’s file upload form. I appreciate any response from now. Here is my code :

          string duration = "00:00:00";
  
  
  
          //converting video
  
          Process ffmpeg;
  
          ffmpeg = new Process();
  
  
  
          // convert to mpg 1st
  
          ffmpeg.StartInfo.Arguments = " -i \"" + Server.MapPath("static/user/vid/") + videolink + "\" -f mpeg -b 300k -ac 2 -ab 128k -ar 44K \"" + Server.MapPath("static/user/vid/") + mpglink + "\"";
  
          ffmpeg.StartInfo.FileName = Page.MapPath("bin/ffmpeg.exe");
  
          ffmpeg.StartInfo.CreateNoWindow = true;
  
          ffmpeg.StartInfo.UseShellExecute = false;
  
          ffmpeg.StartInfo.RedirectStandardOutput = true;
  
          ffmpeg.StartInfo.RedirectStandardError = true;
  
          ffmpeg.Start();
  
  
  
          ffmpeg.WaitForExit();
  
          ffmpeg.Close();
  
  
  
  
  
          // mpg 2 flv
  
          ffmpeg = new Process();
  
          ffmpeg.StartInfo.Arguments = " -i \"" + Server.MapPath("static/user/vid/") + mpglink + "\" -f flv -s 624x352 \"" + Server.MapPath("static/user/vid/") + flvlink + "\"";
  
          ffmpeg.StartInfo.FileName = Page.MapPath("bin/ffmpeg.exe");
  
          ffmpeg.StartInfo.CreateNoWindow = true;
  
          ffmpeg.StartInfo.UseShellExecute = false;
  
          ffmpeg.StartInfo.RedirectStandardOutput = true;
  
          ffmpeg.StartInfo.RedirectStandardError = true;
  
          ffmpeg.Start();
  
  
  
          ffmpeg.BeginOutputReadLine();
  
          string error = ffmpeg.StandardError.ReadToEnd();
  
          ffmpeg.WaitForExit();
  
  
  
          try
  
          {
  
              duration = error.Substring(error.IndexOf("Duration: ") + 10, 8);
  
          }
  
          catch
  
          {
  
          }
  
  
  
          if (ffmpeg.ExitCode != 0)
  
          {
  
              ltrUpload.Text = "<div class="\&quot;resultbox-negative\&quot;">Problem occured during upload process. Error code: " + error + "<br />" + "</div>";
  
              return;
  
          }
  
          ffmpeg.Close();
  
  
  
  
  
          // generate preview image
  
          ffmpeg.StartInfo.Arguments = " -i \"" + Server.MapPath("static/user/vid/") + flvlink + "\" -s 624x352 -ss 00:00:03 -an -vframes 1 -f image2 -vcodec mjpeg \"" + Server.MapPath("static/user/vid/") + flvlink.Replace(".flv", ".jpg") + "\"";
  
          ffmpeg.StartInfo.FileName = Page.MapPath("bin/ffmpeg.exe");
  
          ffmpeg.StartInfo.CreateNoWindow = true;
  
          ffmpeg.StartInfo.UseShellExecute = false;
  
          ffmpeg.StartInfo.RedirectStandardOutput = true;
  
          ffmpeg.StartInfo.RedirectStandardError = true;
  
          ffmpeg.Start();
  
          ffmpeg.WaitForExit();
  
          ffmpeg.Close();
  
  
  
          // deleting original file and mpg
  
          FileInfo fi = new FileInfo(Server.MapPath("static/user/vid/") + videolink);
  
          if (fi.Exists) fi.Delete();
  
          fi = new FileInfo(Server.MapPath("static/user/vid/") + mpglink);
  
          if (fi.Exists) fi.Delete();

• svq1 : do not modify the input packet

  3 août 2014, par Anton Khirnov

  svq1 : do not modify the input packet
  The input data must remain constant, make a copy instead. This is in
  
  theory a performance hit, but since I failed to find any samples
  
  using this feature, this should not matter in practice.
  Also, check the size of the header, avoiding invalid reads on truncated
  
  data.
  CC:libav-stable@libav.org
  

  • [DBH] libavcodec/svq1dec.c