Something is up with h264 encoding on Final Cut Pro 10.4.1, Compressor 4.7

 h264 encoding using either Compressor 4.7 or FCP 10.4.1 on M1 with Sonoma 14.2.1 are showing blockiness with busy/semi busy imagery.

It wasn't like this with previous versions on FCP/Compressor/Pro Video Formats/macOS that I recall.

 h264 encoding behaves very poorly compared to Adobe Media Encoder. I tested both on the same ProRes master, Apple output is dirty where AME is relatively clean. Same data rate, using the default settings.

I tested previous versions of FCP/Compressor on the same machine: Monterey and Ventura, and results are the same: blocky, sloppy, prone to artifacts on certain images.

It was not like this before: I looked at the same h264 export I did in June 2023 with FCP 10.6.6, Pro Video Formats 2.2.5, and Ventura, it was clean throughout. Same machine.

Something happened since, and now it's screwed. What is going on Apple? Anybody seeing a similar problem on their setup?

Below are 4 frame exports of the same image:

1. ProRes export
2. h264 export from FCP
3. h264 export from Compressor
4. h264 export from Adobe Media Encoder

Superimposed to the original sequence. Opacity switched to Difference, and Midtones Exposure pushed to 100%.

1) ProRes

2) h264 Final Cut Pro

3) h264 Compressor

4) h264 Adobe Media Encoder

5) h264 DaVinci Resolve

ProRes looks the best as expected. Clearly Media Encoder h264 output looks much better than Compressor, Final Cut Pro, and Resolve h264 outputs 😵.

Final Cut and Resolve are close, both doing a sloppy job at encoding h264 compared to Adobe Media Encoder. Compressor is the worst of all 😩.

NOT GOOD APPLE!! Not great Blackmagic Design!!