Parallel port trigger tells me when I’m transcoding

I decided to finish up my Cylon Eye (Larson Scanner) project by adding it as a status indicator for my computer. I record over the air programming and transcode it to DVD quality. Since things can be a bit slower when FFmpeg is running, I set it up for the Eye to scan to let me know it’s processing a video file in the background. All the details after the break but here’s the gist of the system:

  • Python script started by the FFmpeg transcoding script
  • It controls the Parallel port, driving pin 1 high to turn on the cylon eye
  • the ‘pidof’ command is called every minute for FFmpeg. When it is not found, the cylon eye is turned off and the script exits

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