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• Limit number of Start-Process running in powershell

  4 mai 2018, par Ahhhhhhhhhhhhhdfgbv

  I have tried to limit the number of Start-Process running from a Powershell, but I can’t seem to get it to work.

  I tried to follow this process : https://exchange12rocks.org/2015/05/24/how-to-limit-a-number-of-powershell-jobs-running-simultaneously/ and Run N parallel jobs in powershell

  But these are for Jobs not Processes, and I would like to remove the -Wait from the Start-Process

  My concern with the script is that if there are 1000 audio files in the folder, then FFMpeg would crash the system.

  ---

  # get the folder for conversion
  
  function mbAudioConvert {
  
      [Reflection.Assembly]::LoadWithPartialName("System.Windows.Forms") | Out-Null
  
      [System.Windows.Forms.Application]::EnableVisualStyles()
  
  
  
      $fileBrowser = New-Object System.Windows.Forms.FolderBrowserDialog
  
      $fileBrowser.SelectedPath = "B:\"
  
      $fileBrowser.ShowNewFolderButton = $false
  
      $fileBrowser.Description = "Select the folder with the audio which you wish to convert to Avid DNxHD 120 25P 48kHz"
  
  
  
      $mbLoop     = $true
  
      $mbCount    = 0001
  
      $mbMaxJob   = 4
  
  
  
      while( $mbLoop ) {
  
          if( $fileBrowser.ShowDialog() -eq "OK" ) {
  
              $mbLoop     = $false
  
  
  
  
  
              $mbImage    = ( Get-Item -Path "C:\Users\user\Desktop\lib\AudioOnly.jpg" )
  
              $mbff32     = ( Get-Item -Path "C:\Users\user\Desktop\lib\ffmpeg32.exe" )
  
              $mbff64     = ( Get-Item -Path "C:\Users\user\Desktop\lib\ffmpeg64.exe" )
  
  
  
              $mbFolder   = $fileBrowser.SelectedPath
  
              $mbItemInc  = ( ls $mbFolder\* -Include *.mp3, *.MP3, *.wav*, *.WAV*, *.ogg, *.OGG, *.wma, *.WMA, *.flac, *.FLAC, *.m4a, *.M4a )
  
              $mbProgress = ( Get-ChildItem -Path $mbItemInc )
  
  
  
              $mbHasRaw   = ( $mbFolder + "\RAW" )
  
  
  
              if( !( Test-Path -Path $mbHasRaw ) ) {
  
                  # force create a RAW folder if it does not exist
  
                  New-Item -ItemType Directory -Force -Path "$mbHasRaw"
  
              }
  
  
  
  
  
              foreach( $mbItem in $mbItemInc ) {
  
  
  
                  $mbCheck    = $false
  
  
  
                  # output the progress
  
                  # Suggestion: You might want to consider updating this after starting the job and do the final update after running ex. Get-Job | Wait-Job to make the progress-bar stay until all processes are finished
  
                  #Write-Progress -Activity "Counting files for conversion" -status "Currently processing: $mbCount" -percentComplete ($mbCount / $mbItemInc.count*100)
  
  
  
                  # limit the run number
  
                  while ($mbCheck -eq $false) {
  
  
  
                      if( (Get-Job -State 'Running').count -lt $mbMaxJob) {
  
  
  
                          $mbScriptBlock = {
  
                              $mbItemName = $using:mbItem.BaseName
  
  
  
                              $mbNewItem  = ( $using:mbFolder + "\RAW\" + $mbItemName + ".mov" )
  
                              $mbArgs     = " -loop 1 -i $using:mbImage -i $using:mbItem -shortest -c:v dnxhd -b:v 120M -s 1920x1080 -pix_fmt yuv422p -r 25 -c:a pcm_s16le -ar 48k -af loudnorm=I=-12 $mbNewItem"
  
  
  
                              Start-Process -FilePath $using:mbff32 -ArgumentList $mbArgs -NoNewWindow -Wait
  
                          }
  
  
  
                          Start-Job -ScriptBlock $mbScriptBlock
  
  
  
                          #The job-thread doesn't know about $mbCount, better to increment it after starting the job
  
                          $mbCount++
  
                          $mbCheck  = $true          
  
                      }
  
  
  
                  }
  
              }
  
  
  
          } else {
  
  
  
              $mbResponse = [System.Windows.Forms.MessageBox]::Show("You have exited out of the automation process!", "User has cancelled")
  
              if( $mbResponse -eq "OK" ) {
  
                  return
  
              }
  
          }
  
      }
  
  
  
      $fileBrowser.SelectedPath
  
      $fileBrowser.Dispose()
  
  }
  
  
  
  # call to function
  
  mbAudioConvert

• Convert .heic to .jpg using ffmpeg ?

  19 novembre 2018, par Ketan Chauhan

  Using MP4Box :

  MP4Box -info IMG_5915.HEIC

  I get :

  prof colour profile not supported

  prof colour profile not supported

  Root Meta type : "pict" - 52 resource item(s)

  Primary Item - ID 49

  Item #1 - ID 1 - Name :
  .

  .

  .

  Item #49 - ID 49 - Name :

  Item #50 - ID 50 - Name : Item #51 - ID 51 - Name :

  File has no movie (moov) - static data container

  Then if I extract all of these :

  for i in seq 51 ; do MP4Box -dump-item $i:path=item$i.hevc
  IMG_5915.HEIC ; done

  Then if i continue, and convert these tiles to jpeg with ffmpeg it convert one tile to jpeg i.e it creates 51 HEVC tiles.

  ffmpeg -i item1.hevc -frames:v 1 -vsync vfr -q:v 1 -an image1.jpg

  How can I combine these tiles into a single jpg file ?

• Writing frames from camera using skvideo.io.FFmpegWriter

  28 juin 2018, par Liam Deacon

  I’m trying to finely control the video encoding of camera image frames captured on the fly using skvideo.io.FFmpegWriter and cv2.VideoCapture, e.g.

  from skvideo import io
  
  import cv2
  
  
  
  fps = 60
  
  stream = cv2.VideoCapture(0)                    # 0 is for /dev/video0
  
  print("fps: {}".format(stream.set(cv2.CAP_PROP_FPS, fps)))
  
  
  
  stream.set(cv2.CAP_PROP_FRAME_WIDTH, 1920)
  
  stream.set(cv2.CAP_PROP_FRAME_HEIGHT, 1080)
  
  print("bit_depth: {}".format(stream.set(cv2.CAP_PROP_FORMAT, cv2.CV_8U)))
  
  
  
  video = io.FFmpegWriter('/tmp/test_ffmpeg.avi', 
  
              inputdict={'-r': fps, '-width': 1920, '-height': 1080},
  
              outputdict={'-r': fps, '-vcodec': 'libx264', '-pix_fmt': 'h264'}
  
  )
  
  
  
  try:
  
      for i in range(fps*10):  # 10s of video
  
          ret, frame = stream.read()
  
          video.writeFrame(frame)
  
  finally:
  
      stream.release()
  
  
  
  try:
  
      video.close()
  
  except:
  
      pass

  However, I get the following exception (in Jupyter notebook) :

  ---------------------------------------------------------------------------
  
  TypeError                                 Traceback (most recent call last)
  
  
  
   in <module>()
  
       18     while range(fps*10):
  
       19         ret, frame = stream.read()
  
  ---> 20         video.writeFrame(frame)
  
       21 except BaseException as err:
  
       22     raise err
  
  
  
  /usr/local/lib/python3.6/site-packages/skvideo/io/ffmpeg.py in writeFrame(self, im)
  
      446         T, M, N, C = vid.shape
  
      447         if not self.warmStarted:
  
  --> 448             self._warmStart(M, N, C)
  
      449 
  
      450         # Ensure that ndarray image is in uint8
  
  
  
  /usr/local/lib/python3.6/site-packages/skvideo/io/ffmpeg.py in _warmStart(self, M, N, C)
  
      412         cmd = [_FFMPEG_PATH + "/" + _FFMPEG_APPLICATION, "-y"] + iargs + ["-i", "-"] + oargs + [self._filename]
  
      413 
  
  --> 414         self._cmd = " ".join(cmd)
  
      415 
  
      416         # Launch process
  
  
  
  TypeError: sequence item 3: expected str instance, int found
  
  </module>

  Changing this to video.writeFrame(frame.tostring()) results in ValueError: Improper data input, leaving me stumped.

  How should I go about writing each frame (as returned by OpenCV) to my FFmpegWriter instance ?

  EDIT

  The code works fine if I remove inputdict and outputdict from the io.FFmpegWriter call, however this defeats the purpose for me as I need fine control over the video encoding (I am experimenting with lossless/near-lossless compression of the raw video captured from the camera and trying to establish the best compromise in terms of compression vs fidelity for my needs).