u/hypespud

A week or two ago I was exploring different options to get a full 4K60 RGB or YUV with HDR stream to my PC

The inspiration comes from Chiaki-ng which utilizes PlayStation's Remote Play feature, although this is capped at 1080p60HDR on a PS5, and comes with other limitations like limited DualSense features while playing through Remote Play

I ended up buying a pair of Elgato 4K X devices to test how the video stream could work with a HDMI input such as from a PS5, and you can likely easily use this with any other similar HDMI output devices

Elgato 4K X benefits:

USB-C connectivity, up to USB 3.2 I believe, and up to 4K120HDR or 8K60HDR support I think (per the device description, I have only used up to 4K60HDR so far)

HDMI input stream, rather than Remote Play:

higher quality streaming up to full 4K120HDR or 4K60HDR input (instead of capping at 1080p60HDR), and the benefit of full controller or DualSense features (haptics, directional rumble, controller speaker features, etc) while connected to the console, as well as access to all other features such as voice groups or settings menu access, some of which are restricted while using Remote Play

Overall benefit:

while there is a delay which is similar to Remote Play while using Elgato 4K X if you are playing looking at the stream through the Elgato 4K X, it is not very large, though it is definitely less responsive than a direct HDMI signal directly into a HDMI TV for example, but you get to for example record gameplay easily, stream gameplay live in Discord or other programs, or even play directly through this screen while using your PC on the same screen

Other notables:

It might be better to not use the Elgato 4K X passthrough HDMI, I *think* it might run more hot with it, and possibly this can contribute to more input delay to the USB-C stream to the PC, at least I felt that was happening

What I was doing was running HDMI from my PS5 Pro to a HDMI 2.1 Splitter (4K60HDR max output)

Also notable, the Elgato 4K X stream to the USB-C can *only support stereo* this is also listed on their product pages I believe, be aware of this so you do not expect 5.1 or 7.1 surround DTS or something through the USB-C stream to the PC, I believe it still passes through 5.1 or 7.1 audio through the HDMI passthrough though, but again, limited to stereo sound on the USB-C stream, which may lead to dropped sounds and audio missing if you have the console/HDMI input set to a higher channel audio input

Example, I was playing Saros and I noticed the audio log voices and even the cutscenes audio voices were not playing any sound at all, because the console was set to 7.1 channels, and was working fine as 7.1 on the splitter going towards my TV and sound system

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Instructions

#remember to turn off hdcp on your device, as streaming capture may be incompatible with hdcp copyright protection, or other handshake features with hdmi input

#first connect your elgato 4k x device to your hdmi device, and plug the hdmi device to the *input* of the elgato device, then plug the usb-c to the usb-c of your target linux pc system for the stream, this usb-c will also power the elgato 4k x with no additional wires needed which is great

#ideally, this should be a usb 3.2 input into the pc, most likely directly connecting to the rear of your pc which should be directly into the motherboard, if your motherboard is new enough, check your mobo system specifications online for more information

#install flatpak of mpv https://flathub.org/en/apps/io.mpv.Mpv

#install a program which can view video input sources for linux

sudo dnf install v4l2-ctl

#list devices which can be utilized for streaming e.g. video0 or video1, usually video3 is for metadata only

v4l2-ctl --list-devices

#you can also use an unofficial tool for elgato 4k linux https://github.com/13bm/elgato4k-linux

#open the following commands where the linux version of elgato 4k x linux is located, needs sudo privileges to have usb access

#view firmware version information

sudo ./elgato4k-linux --firmware-version

#view status to read current settings including firmware, usb speed, hdmi color range, and hdr tone mapping setting

sudo ./elgato4k-linux --status

#if hooked correctly should list settings as 10 Gbps (SuperSpeed+) to allow for 4k60hdr rgb, this may also depend on your screen and TV to the maximum it might support from the usb-c input

#Reading current settings from 4K X (PID: 0x009b)...

#Firmware version: 25.08.15

#USB speed: 10Gbps (SuperSpeed+)

#HDMI color range: Auto

#HDR tone mapping: On

#if hooked incorrectly, it may show usb2.0 speeds of 480 mbps, and it will self cap the video to 720p30 no matter what video settings are used, can try re-plugging the hi-speed usb 3.2 cable into the elgato 4k x device and the pc again so it connects at the correct speed

#run the video stream into the flatpak version of mpv, this may only include video

#you may have to set /dev/video0 or /dev/video1, you can use the ( sudo ./elgato4k-linux --status ) from earlier to check this

#this will get the video stream working, but there may not be audio included

flatpak run io.mpv.Mpv av://v4l2:/dev/video0 --profile=low-latency --untimed --framedrop=no --cache=no --demuxer-lavf-o=video_size=3840x2160,framerate=60

#use pulse audio control to list audio sources, note the name of the input audio source to include in the following step

pactl list sources short

#notate the audio device input listed here to include in the next commands

#run the video stream into the flatpak version of mpv, with a combination of audio input from the input usb device

#remember to set the correct video & audio source

flatpak run io.mpv.Mpv av://v4l2:/dev/video0 --profile=low-latency --untimed --framedrop=no --cache=no --demuxer-lavf-o=video_size=3840x2160,framerate=60 & pw-loopback -i "alsa_input.usb-Elgato_Elgato_4K_X_A7SNB55031B03P-02.analog-stereo"

#or another example

#to get the sound to work, you may have to set sound settings input to elgato 4k x analog stereo in your sound devices options, this may disable other microphones connected to your pc as input

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And after that, you should be done! Cheers 😎💎🍻

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