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• Clojure shell/sh does not handle single-quoted arguments correctly ?

  14 juillet 2016, par Jarzka

  Executing the following command in the REPL :

  (shell/sh "ls" "-lah" "'resources'")

  gives the following output :

  {:exit 2, :out "", :err "ls: cannot access 'resources': No such file or directory\n"}

  Executing the same command in the Bash shell gives the correct output, the list of files in the resources directory. To my understanding this means that shell/sh is unable to handle single-quoted arguments correctly. Is this true or am I doing something wrong ?

  The example above is a simple example, as usually I probably would not need to single-quote the folder name. But why this is a real problem is because I try to concat audio files by executing the following ffmpeg command using shell/sh ;

  ffmpeg -i resources/ffmpeg_working/1.flac
  
  -i resources/ffmpeg_working/2.flac
  
  -i resources/ffmpeg_working/3.flac
  
  -i resources/ffmpeg_working/4.flac
  
  -filter_complex '[0:0][1:0][2:0][3:0]concat=n=4:v=0:a=1[out]'
  
  -map '[out]'
  
  resources/ffmpeg_working/done.flac

  This gives the following output

  Stream map ''[out]'' matches no streams.

  Once again, if I execute the same ffmpeg command in the Bash shell it concatenates the files successfully. Thus, it seems that the single-quoted argument is not handle correctly ?

• Clojure shell/sh does not handle single-quoted arguments correctly ?

  3 janvier 2020, par Jarzka

  Executing the following command in the REPL :

  (shell/sh "ls" "-lah" "'resources'")

  gives the following output :

  {:exit 2, :out "", :err "ls: cannot access 'resources': No such file or directory\n"}

  Executing the same command in the Bash shell gives the correct output, the list of files in the resources directory. To my understanding this means that shell/sh is unable to handle single-quoted arguments correctly. Is this true or am I doing something wrong ?

  The example above is a simple example, as usually I probably would not need to single-quote the folder name. But why this is a real problem is because I try to concat audio files by executing the following ffmpeg command using shell/sh ;

  ffmpeg -i resources/ffmpeg_working/1.flac
  
  -i resources/ffmpeg_working/2.flac
  
  -i resources/ffmpeg_working/3.flac
  
  -i resources/ffmpeg_working/4.flac
  
  -filter_complex '[0:0][1:0][2:0][3:0]concat=n=4:v=0:a=1[out]'
  
  -map '[out]'
  
  resources/ffmpeg_working/done.flac

  This gives the following output

  Stream map ''[out]'' matches no streams.

  Once again, if I execute the same ffmpeg command in the Bash shell it concatenates the files successfully. Thus, it seems that the single-quoted argument is not handle correctly ?

• Detecting Successful Conversion with ffmpeg

  22 février 2017, par J M

  I have code that scans a file system for videos files encoded with H.264 and re-encodes them with H.265. It runs pretty much on its own constantly, generating various log files for me to review periodically.

  One thing that I want to further improve is the successful conversion detection. Right now, a file returns as being successfully converted after it meets these criteria/checks :

  1. The output file exists
  2. ffprobe can detect that the output file is in hevc format
  3. The duration of the output file matches that of the input file (within 3 seconds)
  4. The length of the output file is greater than 30 MB (it’s rare that I have a video so short where after conversion it is less than this, usually this happens when an error occurs or conversion terminates early).

  Obviously, this is rather computationally intense as there are many file checks to confirm all of this information. I do this because if the file is detected as successful conversion, the old file is overwritten and the new converted file takes it’s place. I don’t want to overwrite a file because I overlooked a scenario where I think conversion is successful but was in fact not. The files are under a crashplan constant backup, so I don’t lose them, but I also do not go through and review every file.

  So, my basic question is if you see any area of improvement for this detection. My goal is to determine, to my best extent, if after conversion the video remains "playable". So deciding programmatically how/what that means is what I’m attempting to do.

  I can post code if you want it (powershell), but the question seems independent of actual program language choice.