Recherche avancée

Sur d’autres sites (7342)

• Elixir long running background task doesn't complete, sometimes crashes

  29 mars 2018, par Kulix

  As a little bit of background, I have an endpoint that is responsible for video upload. What I want to do, is copy the video file to a temporary location from the request, and spin up an asynchronous task (ffmpeg shell process) to transcode that video in the background so that my endpoint can return a 200 in a timely manner, and the response does not wait for ffmpeg to finish transcoding that video.

  Here is my code from the controller.

  def create(conn, %{"file" => file ... })
  
      uuid = Video.uuid()
  
      tmp_path = Application.get_env(:myapp, :video_tmp_path) <> "/" <> uuid
  
      :ok = File.cp(file.path, tmp_path)
  
      VideoService.process(tmp_path, final_path)

  The inside of VideoService looks like the following.

  defmodule MyApp.Services do
  
    defmodule VideoService do
  
      def process(tmp_path, final_path) do
  
        Task.start_link fn ->
  
          System.cmd("ffmpeg", ["-i", tmp_path, final_path, "-hide_banner"])
  
          File.rm(tmp_path)
  
        end
  
      end
  
    end
  
  end

  The problem I am having here is that no matter what, nothing past the System.cmd("ffmpeg") call executes in the VideoService, and sometimes the System.cmd call doesn’t even spin up an ffmpeg process. Am I doing something wrong here ? What I need is a way to spin this ffmpeg shell process out in the background from the controller / service and respond with a 200 on video upload. Thanks for help in advance. I am new to elixir / OTP, so I’m sure I’m doing something stupid.

  I also randomly see the following error

  erl_child_setup: failed with error 32 on line 240

• 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

• Trying to pull in https paths into ffmpeg for node-js running on aws ec2 fails with 'input file does not exist'

  11 juin 2018, par Auniq

  I have a script set up to load in a video file from an s3 bucket into a node script running on an ec2 instance, but I am having issues trying to get ffmpeg to accept the url. I know that my aws-sdk integration is working ok as I can read objects and write objects to the bucket, and I am generating a signed url to the object in order to easily pass the path through but it seems to be failing with an ’input file does not exist’ error.

  If I use this generated signed path in a browser however, the video file can be found.

  Has anyone else come across this issue ? I could probably try and pipe through the external file to a new file local to the ec2 instance but if I can get round that extra step that would be great !