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• Slow start time in FFmpeg conversion - Seeking advice on optimization and identifying unnecessary flags [closed]

  30 novembre 2023, par Mohamed Dhouib

  I'm currently facing an issue with the startup time of FFmpeg conversion from RTSP stream to DASH stream in my application.
The conversion process takes longer to initiate than expected (sometimes even 15 seconds), impacting overall performance.
I've provided the relevant FFmpeg used options flags below :

  


      "-g 48",
    "-map 0:v:0",
    "-pix_fmt yuv420p",
    "-f dash",
    "-window_size 5",
    "-use_template 1",
    "-g 48",
    "-sc_threshold 0",
    "-vf scale=1920:1080",
    "-c:a aac",
    "-ar 48000",
    "-ac 2",
    "-strict experimental",
    "-max_muxing_queue_size 1024",
    "-c:v libx264",
    "-use_timeline 0"
    `-preset medium`,
    `-b:v 500k`,
    `-s 1280x720`,
    `-r 30`


  


  I'm looking for guidance on optimizing the FFmpeg configuration by adding new flags or identifying any unnecessary flags that might contribute to the slow start time.
The goal is to reduce the time it takes for FFmpeg to start the conversion process.
I appreciate any insights or recommendations on how to improve the startup time of FFmpeg conversion in my application.

  


  Relevant Dependencies :

  


  "@ffmpeg-installer/ffmpeg" : "^1.1.0",
"fluent-ffmpeg" : "^2.1.2",

  


  I am expecting the first stream chunk to be created in the first 3 seconds or so but it takes a lot more than that ( about 10 seconds )

  


• Limit number of Start-Process running in poweshell

  7 mars 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

• avfilter/af_adynamicequalizer : always start filtering from unit gain

  5 novembre 2023, par Paul B Mahol

  avfilter/af_adynamicequalizer : always start filtering from unit gain
  

  • [DH] libavfilter/adynamicequalizer_template.c
  • [DH] libavfilter/af_adynamicequalizer.c