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• FFMPEG aspect parameter cannot actually set aspect ratio [on hold]

  8 août 2014, par yasi

  I want to generate an h264 (avc) file by a jpg file. I generated it by command :

  • ffmpeg -f image2 -i img%d.jpg -vcodec libx264 sample.h264
  • mv avatar.h264 sample-320.avc

  the img%d.jpg is 0.jpg, 1.jpg, 2.jpg ... 24.jpg, all of which is the same, resolution is 320x180

  When sample.avc is generated, I checked information of it by ESEyE, it’s like below.
  

  As you can see, the resolution is correct, but aspect ratio is weird since original jpg sequence is 320x180, whose aspect ratio is 16:9. So, I tried to keep 16:9 by the command below

  • ffmpeg -r 25 -f image2 -i img%d.jpg -vcodec libx264 -profile:v baseline -level:v 1.1 -aspect "16:9" sample.h264

  However, it doesn’t work, the generated avc aspect ratio is still 5x3.

  How can I keep aspect ratio of 16:9 ?

  P.S.
  I guess h264 miminal block is 16x16, and avc width could be padded as 192 (16 * 12), so aspect ratio is 320:192 = 5:3.

• Can't execute FFMPEG command in C#

  15 août 2017, par JasonJerry

  I am trying to automate a HLS to mp4 FFMPEG encoding process in c# using this code :

  public static void startFFMPEG()
  
      {
  
          string url = hlsStream.getHLS();
  
  
  
          using (Process p = new Process())
  
          {
  
              p.StartInfo.UseShellExecute = false;
  
              p.StartInfo.CreateNoWindow = false;
  
              p.StartInfo.RedirectStandardOutput = true;
  
              p.StartInfo.FileName = "ffmpeg.exe";
  
              p.StartInfo.Arguments = $"-i {url} -c copy output.mp4";
  
              p.Start();
  
              p.WaitForExit();
  
          }
  
  
  
      }

  The code is doing what it should be but FFMPEG replies with the error

  Server returned 400 Bad Request

  The is weird because executing the command with the exact same arguments manually through a command prompt works fine.

  I also tried to use

          p.StartInfo.FileName = "cmd.exe";
  
          p.StartInfo.Arguments = $"ffmpeg -i {url} -c copy output.mp4";

  which resulted in a other FFMPEG error

  At least one output file must be specified

• VLC libx264 streaming muxed as FLV

  24 mars 2012, par Jan Novák

  I have a question on streaming output of libx264. My scenario is that Iam capturing video from webcam, encoding with x264 and then streaming data to flash, muxed as FLV. For muxing, Im using output/flv_bitstream.h, included in libx264 budle. The only modification of muxer, that I made, is that instead of fwrite() im usig send() to transfer data via socket... Encoding library is working fine. If I save output (even muxed), vlc player is able to play it. But, when it goes to data transfer via socket, vlc and flash are not cooperating. The weird thig is, that if Im sending data to vlc player thru socket, it waits till transmission end and then plays video from buffer. But what I need is to play live stream.

  I also tryed to read flv file and send it to vlc of flash tag by tag and it is working fine.

  Any suggestions ?