HDMI默认输出颜色格式是YUV444吗

Chip Platform Rockchip
1

AIO-3566JD4这块板子HDMI输出颜色格式是YUV444吗？
可以更改成RGB888吗，请问如何更改呢？

2

桌面系统：
Distributor ID: Ubuntu
Description: Ubuntu 18.04.5 LTS
Release: 18.04
Codename: bionic

3 
# cat /sys/kernel/debug/dw-hdmi/status
PHY: enabled                    Mode: HDMI
Pixel Clk: 148500000Hz          TMDS Clk: 148500000Hz
Color Format: YUV444            Color Depth: 8 bit
Colorimetry: ITU.BT709          EOTF: Off