Video can be recorded to an external device via HDMI at 4K/60P 4:2:2 10 bit or internally at 4K/60P 4:2:0 10bit.
Like the X-T3, the X-T4 supports H.264/MPEG-4 AVC as well as H.265/HEVC, which offers a higher rate of compression, when recording 4K/60P 4:2:0 10 bit video at a bit rate of 200Mbps.
However, you can now choose MP4 in addition to the standard MOV video file format, broadening where you can use the files.