Livestream to YouTube in 4K with OBS?

[creat0r]

The company I work for is going to try to do a livestream on YouTube. We have good cameras, very powerful computers and a pretty fast and stable fibre internet connection (250 Mbps up/down). However, we were wondering about the resolution and FPS limitations of livestreaming via OBS to YouTube:

1. Can you livestream to YouTube in 4K 25 FPS via OBS?
2. Will people watching be able to watch in 4K in real time, or will the live be 1080p (and only the video after the finished livestream 4K)?
3. Is anyone able to find someone that has livestreamed to YouTube in 4K (WAN Show seems to be 1080p only)?
4. (Bonus questions: Will OBS be mostly demanding on the CPU or GPU?)

[Tanaz]

Yes, there are live streams currently working in 4K and yes people will be able to watch and react. OBS will be demanding on both, even if you use the GPU for encoding the stream itself, the CPU plays a part in complex scenes especially if you're going to be encoding  camera feed as well. Are you going to be using DSLR/Mirrorless cameras + capture cards or are you talking about some sort of 4K webcams?

[creat0r]

16 minutes ago, Tanaz said:

Yes, there are live streams currently working in 4K and yes people will be able to watch and react. OBS will be demanding on both, even if you use the GPU for encoding the stream itself, the CPU plays a part in complex scenes especially if you're going to be encoding  camera feed as well. Are you going to be using DSLR/Mirrorless cameras + capture cards or are you talking about some sort of 4K webcams?

Thanks! Impressive that it is possible to livestream 4K on YouTube.

Setup: Panasonic GH5 (2 cameras) + Elgato Cam Link 4K (USB) + MacBook Pro 16" M1 Max 32 GB + OBS (with green screen filter on both cameras). 

[Tanaz]

10 hours ago, creat0r said:

Thanks! Impressive that it is possible to livestream 4K on YouTube.

Setup: Panasonic GH5 (2 cameras) + Elgato Cam Link 4K (USB) + MacBook Pro 16" M1 Max 32 GB + OBS (with green screen filter on both cameras). 

You're gonna have to ask a Mac user to be honest because I have no idea how Apple silicon works with OBS and if it supports some sort of hardware encoding. In theory it should be plenty of powerful enough but then again you have 2 Camlinks and 2 Cameras so you might need a PC build after all. Only way to find out is by testing the current setup.

[creat0r]

8 hours ago, Tanaz said:

You're gonna have to ask a Mac user to be honest because I have no idea how Apple silicon works with OBS and if it supports some sort of hardware encoding. In theory it should be plenty of powerful enough but then again you have 2 Camlinks and 2 Cameras so you might need a PC build after all. Only way to find out is by testing the current setup.

Yes we tested it and it works great, about 40% CPU/GPU usage when broadcasting with both cameras and the green screen filter applied. M1 Max has hardware coding for H.264 & HEVC (H.265), so not the newest fanciest streaming codecs but there won’t be a lot of movement in the scene so it should be fine with an adequate bitrate setting.