title: ffmpeg-python tracking transcoding process
body: <p>My question is based on <a href="https://github.com/kkroening/ffmpeg-python/blob/master/examples/show_progress.py" rel="nofollow noreferrer">https://github.com/kkroening/ffmpeg-python/blob/master/examples/show_progress.py</a>
  Ideally, all I want is to keep track e.g 0 - 100 for the transcoding process, emitting a streaming yield response to my gRPC client. Technically, I do not need a progress bar.
  How can I provide my own socket to the ffmpeg subprocess and handle write events to it?</p>