Ffmpeg to Final cut

What does MediaInfo or Invisor report about the Compressor output?

With your ffmpeg command...

ffmpeg -i blank.mp4 -c:v libx264 -preset fast -crf 26 -profile:v baseline -pix_fmt yuv420p -vf scale=3840:2160 -r 30 -c:a copy output.mp4

...the -mp4 plays OK on Sonoma QuickTime Player and Invisor report is:

Let me see if I am understanding you correctly:

you have a video file on your mac, and need to convert it in order to play on your pc?

Most files that you'd output from FCP, Quicktime Player or Compressor should just work.

Please open the problem file in Quicktime Player, press Command-I and post a screenshot.

Also, if you export from FCP: Export File->Computer, it will produce an .mp4 file that will play just about anywhere.

My guess is that have probably just exported in ProRes. ProRes is great for video editing but is not available by default in either macs, or pcs - you need to install software like FCP in your mac before you can use ProRes.

Never use ProRes to distribute your videos. Use H264, in .mov or .mp4 container, and it will play in any mac, pc, phone...

Share > Export File > H.264

I do this daily, they play on Windows machines just fine.