I checked on my side with a fresh installation of latest image with oowow, it works and I can use gstreamer to record a video from it.
khadas@Khadas:~$ cat /etc/fenix-release
# PLEASE DO NOT EDIT THIS FILE
BOARD=VIM4
VENDOR=Amlogic
VERSION=1.4
ARCH=arm64
INITRD_ARCH=arm64
IMAGE_VERSION=1.4-221229
################ GIT VERSION ################
UBOOT_GIT_VERSION=khadas-vims-u-boot-2019.01-v1.4-release
LINUX_GIT_VERSION=khadas-vims-linux-5.4-v1.4-release
FENIX_GIT_VERSION=v1.4
#############################################
khadas@Khadas:~$ ls /dev/video50
/dev/video50
khadas@Khadas:~$ gst-launch-1.0 v4l2src device=/dev/video50 io-mode=mmap num-buffers=300 ! amlvenc ! h264parse ! qtmux ! filesink location=test_50.mp4
Setting pipeline to PAUSED ...
Pipeline is live and does not need PREROLL ...
Pipeline is PREROLLED ...
Setting pipeline to PLAYING ...
New clock: GstSystemClock
Set log level to 4
[initEncParams:190] enc_feature_opts is 0x1 , GopPresetis 0x0
[vdi_sys_sync_inst_param:675] [VDI] fail to deliver sync instance param inst_idx=0
[AML_MultiEncInitialize:1389] VPU instance param sync with open param failed
[SetSequenceInfo:990] Required buffer fb_num=3, src_num=1, actual src=3 3840x2160
Redistribute latency...
Redistribute latency...
Got EOS from element "pipeline0".
Execution ended after 0:00:13.744357674
Setting pipeline to NULL ...
Freeing pipeline ...
For Guvcview on VIM4, you need ectra steps to fix it, please check the documentation to install a package and try again.
https://docs.khadas.com/products/sbc/vim4/troubleshooting/ubuntu22.04-fixup
Here it the result on my side, it works.
