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• FPS shown in ffmpeg does not match with total frames/duration

  14 juin 2020, par Lincolnhuj

  FPS is defined as number of frames per second. But when I try to calculate FPS using total frames / duration, I get slightly different number than the FPS shown in ffmpeg :

  



  For this video http://commondatastorage.googleapis.com/gtv-videos-bucket/sample/ForBiggerFun.mp4
using ffmpeg, we can get its FPS, duration and total frames :

  



  


  ffprobe -select_streams v -show_streams ForBiggerFun.mp4 | grep nb_frames

  


  



  nb_frames=1440

  



  


  ffmpeg -i ForBiggerFun.mp4

  


  



  23.98 fps
Duration : 00:01:00.07

  



  If we calculate duration per frame using nb_frames, we get
fps = nb_frames/Duration = 1440/60.07 = 23.972032628599965, which is different from 23.98

  



  Which value is more reliable ? Does the difference means duration of a frame might be different from others (frames are not evenly distributed) ?

  


• PHP - Upload video convert mp4 and upload to Amazon S3

  31 octobre 2019, par Kadir Geçit

  I’m using amazon s3 as video storage for my website. I’m having problems for some videos. black screen or sound problems etc.

  I want to convert the video to mp4 format after uploading the video to my server and then upload it to amazon. Is it possible with FFMPEG ?

  I’m using this code for uploading files now :

  $file1 = $_FILES['file']['name'];
  
  $videoFileType = strtolower(pathinfo($file1,PATHINFO_EXTENSION));
  
  $file_name = sprintf('%s_%s', uniqid(),uniqid().".".$videoFileType);
  
  $temp_file_location = $_FILES["file"]["tmp_name"];
  
  
  
  require 'application/libraries/Amazon/aws-autoloader.php';
  
          $s3 = new Aws\S3\S3Client([
  
              'region'  => $amazon_region,
  
              'version' => 'latest',
  
              'credentials' => [
  
              'key'    => $amazon_key,
  
              'secret' => $amazon_secret,
  
              ]
  
          ]);     
  
  
  
          $result = $s3->putObject([
  
              'Bucket' => $amazon_bucket,
  
              'Key'    => $file_name,
  
              'SourceFile' => $temp_file_location,
  
              'ACL'    => 'public-read',
  
              'CacheControl' => 'max-age=3153600',
  
          ]);
  
              $filepath = $result['ObjectURL'] . PHP_EOL;
  
  
  
              echo json_encode([
  
                  'status' => 'ok',
  
                  'path' => $filepath
  
  
  
              ]);

• ffmpeg from a C# app using Process class - user prompt not shown in standardError

  21 avril 2016, par DarwinIcesurfer

  I am writing an app to run ffmpeg using c#. My program redirects the standardError output to a stream so it can be parsed for progress information.

  During testing I have found a problem :

  If the output is shown in a command window rather than being redirected ffmpeg will display it’s normal headers followed by "file c :\temp\testfile.mpg already exists. overwrite [y]". If I click on the command window and press y the program continues to encode the file.

  If the StandardError is redirected to my handler and then printed to the console, I see the same header information that was displayed in the command window now printed to the console. except for the file...already exists prompt. If I click in the command window and press y the program continues to process the file.

  Is there a stream other than standardOutput or standardError that is used when the operator is prompted for information, or am I missing something else ?

  public void EncodeVideoWithProgress(string filename, string arguments, BackgroundWorker worker, DoWorkEventArgs e)
  
      {
  
  
  
          Process proc = new Process();
  
  
  
          proc.StartInfo.FileName = "ffmpeg";
  
          proc.StartInfo.Arguments = "-i " + " \"" + filename + "\" " + arguments;
  
  
  
          proc.StartInfo.UseShellExecute = false;
  
          proc.EnableRaisingEvents = true;
  
  
  
          proc.StartInfo.RedirectStandardError = true;
  
          proc.StartInfo.RedirectStandardOutput = false;
  
          proc.StartInfo.CreateNoWindow = false; //set to true for testing
  
  
  
          proc.ErrorDataReceived += new DataReceivedEventHandler(NetErrorDataHandler);
  
  
  
          proc.Start();
  
          proc.BeginErrorReadLine();
  
  
  
  
  
          StreamReader reader = proc.StandardOutput;
  
           string line;
  
           while ((line = reader.ReadLine()) != null)
  
          { Console.WriteLine(line); }
  
       proc.WaitForExit();
  
  }
  
  
  
  private static void NetErrorDataHandler(object sendingProcess,
  
                 DataReceivedEventArgs errLine)
  
      {
  
          if (!String.IsNullOrEmpty(errLine.Data))
  
          {
  
              Console.WriteLine(errLine.Data);
  
          }
  
      }