@lackyluuk the /etc/init.d/S06splash script is based on the height of the framebuffer to display the video.
| # cut -d, -f2 /sys/class/graphics/fb0/virtual_size |
| 1024 |
On my 4/3 1280x1024 screen the videos are well displayed. But as the videos are natively in 1920x1080, there are black stripes at the top and bottom.
As your resolution is not standard, the value returned by the function must not be good.
Try to add the following configuration at the end of the /boot/config.txt file to tune your own resolution
| disable_overscan=1 |
| hdmi_group=2 |
| hdmi_mode=87 |
| hdmi_cvt=1024 600 3 0 0 0 |
Tell me if it is better.