Raspberry Pi 4 + DietPi: no /dev/video* with dtoverlay=rpivid-v4l2 on 6.12.62+rpt kernel (Moonlight HW decode)

Troubleshooting
1

  • DietPi version | DietPi v10.0.1
  • Distro version | trixie
  • Kernel version | Linux DockerPi 6.12.62+rpt-rpi-v8 #1 SMP PREEMPT Debian 1:6.12.62-1+rpt1 (2025-12-18) aarch64 GNU/Linux
  • Architecture | arm64
  • SBC model | RPi4
  • Power supply used | RPi PSU
  • SD card used | SSD

Raspberry Pi 4 + DietPi: no /dev/video* with dtoverlay=rpivid-v4l2 on 6.12.62+rpt kernel (Moonlight HW decode)

Hi all,

I’m trying to get V4L2 hardware video decoding working on a Raspberry Pi 4 running DietPi so I can use Moonlight with hardware decode. Moonlight itself is fine, but the system has no V4L2 decoder devices at all, so there’s nothing for Moonlight (or FFmpeg) to use.

Environment

  • Device: Raspberry Pi 4 (4GB)

  • OS: DietPi (64‑bit, aarch64)

  • Kernel:

uname -a
Linux DockerPi 6.12.62+rpt-rpi-v8 #1 SMP PREEMPT Debian 1:6.12.62-1+rpt1 (2025-12-18) aarch64 GNU/Linux

Current boot config

Relevant part of my /boot/config.txt:

#-------GPU memory splits-------
gpu_mem=256

arm_64bit=1
dtoverlay=disable-wifi
dtoverlay=vc4-kms-v3d
dtoverlay=rpivid-v4l2

# HDMI
hdmi_group=1
hdmi_mode=16      # 1080p60 CEA
disable_overscan=1

Same dtoverlay=rpivid-v4l2 line appears in /boot/firmware/config.txt as well.

Symptoms

Despite the above:

bash

ls -l /dev/video*
ls: cannot access '/dev/video*': No such file or directory

dmesg | grep -Ei 'rpivid|bcm2835-codec|v4l2'
# (no output)

v4l2-ctl --list-devices
# (no output)

Trying to inspect the expected decoder nodes fails as there are none:

bash

v4l2-ctl -d /dev/video10 --all
Cannot open device /dev/video10, exiting.

v4l2-ctl -d /dev/video11 --all
Cannot open device /dev/video11, exiting.

Moonlight is being launched directly from a TTY via a system service (not inside Docker), so this isn’t a container device‑mapping issue.

What I’ve checked

Kernel config and overlays:

bash

zgrep RPIVID /proc/config.gz 2>/dev/null || echo "no RPIVID options in kernel config"
no RPIVID options in kernel config

ls /boot/firmware/overlays/rpivid*
ls: cannot access '/boot/firmware/overlays/rpivid*': No such file or directory

So it looks like:

  • The current 6.12.62+rpt-rpi-v8 kernel has no RPivid options built in.

  • The firmware set does not ship rpivid-v4l2.dtbo either.

That would explain why dtoverlay=rpivid-v4l2 is effectively a no‑op and why no /dev/video* devices appear.

Questions

  1. On current DietPi for Raspberry Pi, is RPivid/V4L2 hardware decoding intentionally removed from the 6.12.x +rpt kernels?

  2. What is the recommended way (on DietPi) to get a kernel/firmware combo that does provide RPivid and the corresponding overlay?

I’d like to keep the rest of this DietPi install as‑is and just use whatever kernel/firmware path you recommend to get /dev/video10/11/12 back for V4L2 hardware decoding.

Happy to provide any additional logs or try test kernels if needed. I used AI to help draft this post and it seems accurate, but apologies for any errors. Thanks!

2

We from DietPi team don’t maintain the kernel. It’s the original one from RPi foundation.

3

Did you activate RPI-codecs with dietpi-config?
On my RPi4 I get

root@RPi4:~# uname -a
Linux RPi4 6.12.62+rpt-rpi-v8 #1 SMP PREEMPT Debian 1:6.12.62-1+rpt1 (2025-12-18) aarch64 GNU/Linux

root@RPi4:~# ls -l /dev/video*
crw-rw---- 1 root video 81, 1 17. Jan 23:00 /dev/video10
crw-rw---- 1 root video 81, 2 17. Jan 23:00 /dev/video11
crw-rw---- 1 root video 81, 3 17. Jan 23:00 /dev/video12
crw-rw---- 1 root video 81, 4 17. Jan 23:00 /dev/video18
crw-rw---- 1 root video 81, 0 17. Jan 23:00 /dev/video19
crw-rw---- 1 root video 81, 5 17. Jan 23:00 /dev/video31

root@RPi4:~# dmesg | grep -Ei 'rpivid|bcm2835-codec|v4l2'
[    4.907422] bcm2835-codec bcm2835-codec: Device registered as /dev/video10
[    4.907452] bcm2835-codec bcm2835-codec: Loaded V4L2 decode
[    4.912592] bcm2835-codec bcm2835-codec: Device registered as /dev/video11
[    4.912618] bcm2835-codec bcm2835-codec: Loaded V4L2 encode
[    4.915395] bcm2835-codec bcm2835-codec: Device registered as /dev/video12
[    4.915422] bcm2835-codec bcm2835-codec: Loaded V4L2 isp
[    4.917129] bcm2835-codec bcm2835-codec: Device registered as /dev/video18
[    4.917154] bcm2835-codec bcm2835-codec: Loaded V4L2 image_fx
[    4.919334] bcm2835-codec bcm2835-codec: Device registered as /dev/video31
[    4.919361] bcm2835-codec bcm2835-codec: Loaded V4L2 encode_image

root@RPi4:~# v4l2-ctl --list-devices
bcm2835-codec-decode (platform:bcm2835-codec):
        /dev/video10
        /dev/video11
        /dev/video12
        /dev/video18
        /dev/video31

rpi-hevc-dec (platform:rpi-hevc-dec):
        /dev/video19
        /dev/media0

bcm2835-codec (vchiq:bcm2835-codec):
        /dev/media1

I don’t use rpivid-v4l2 nor vc4-kms-v3d tho, you don’t need it for decoding support

root@RPi4:~# grep dtoverlay /boot/config.txt
dtoverlay=disable-wifi
dtoverlay=argonone

For moonlight /dev/video10 (comes from bcm2835-codec) should be enough

edit:

I just found out rpivid-v4l2 is deprecated, bcm2835-codec + rpi-hevc-dec stack is the way to go.