Videos: Improve hardware transcoding on Synology NAS devices

[sunbeam60]

On Synology NAS devices (and possibly other setups, /dev/dri/renderD128 has permissions 'u=rw,g=,o=' and is owned by user "videodriver".

This configuration prevents hardware transcoding using h264_qsv as the VAAPI device cannot be unless the Synology user runs the docker package as root:

/usr/bin/ffmpeg -qsv_device /dev/dri/renderD128 -i /photoprism/originals/2022/02/27/IMG_8370.MOV -c:a aac -vf format=rgb32 -c:v h264_qsv -vsync vfr -r 30 -b:v 25M -maxrate 25M -f mp4 -y /photoprism/storage/sidecar/2022/02/27/IMG_8370.MOV.avc"
[SNIP]
Failed to create a VAAPI device

If the file permissions for /dev/dri/renderD128 inside the container is set to 'u=rw,g=rw,o=rw', PhotoPrism's invocation of ffmpeg with h264_qsv succeeds.

This is a common issue for docker containers using hardware transcoding and it seems the common pattern it to iterate across the dev/dri/render devices, ensuring groups have rw rights and adding whatever group the docker's user belongs to as group owners.

[lastzero]

Do you know what ID the user videodriver has?

[lastzero]

As described in the release notes, the upcoming preview build includes default user accounts for common user ID ranges (50-99, 500-549, 1000-1099) that belong to the groups photoprism (1000), video (44), and render (109):

• If this does not meet your requirements, we can add other users/groups if you provide us with the specific IDs
• I'd rather not change the permissions for the host device inside a guest container if we can find another solution

[sunbeam60]

Do you know what ID the user videodriver has?

uid=937(videodriver) gid=937(videodriver)
... on my Synology. Whether that's persistent across Synology devices, I shan't say.

Apologies for late response - been away for Easter. Sounds like that's not part of the default range you've proposed.

[lastzero]

No, I'm bad at guessing IDs correctly ;)

Now also spending time with my family...

[lastzero]

If you find a way to open a terminal to execute commands in the container, you could try this manually first to save us some time / reduce feedback loops.