title: FFMPEG force_keyframes multiple / several times
body: <p>I am looking for the correct way to use ffmpeg argument force_key_frames at multiple times in a transcode job. As an example right now I can us force_key_frames 0:00:22 to force a keyframe at 22 seconds, but I need both more granularity forcing at fram level as well as being able to select more time points in the job to have forced key frames. </p>
  
  <p>Maybe one at 3 minutes 32 seconds 15 frames and another at 8 minutes 16 seconds 11 frames and so on. </p>