Thanks for the response. I'm trying this and when I go to the console, and try to run ffmpeg, it says the command isn't found. See the attached screenshot. I tried it with the arguments originally, but once it told me ffmpeg wasn't found, I figured there must be a bigger issue.
Edit:
I went into the console and CD'd into /config/FFmpeg and ran ./ffmpeg with the arguments given within compressarr. The error made me realize I had chosen a hardware decoder (vaapi) when I didn't provide one to the docker. I removed the hardware decoder and it seems to be running now.
Thanks!