Latest OBS Producing Recordings Only Decoded by CPU?


New Member

I have come across the strangest problem tonight while attempting to record a 4K Assetto Corsa onboard video.

For some reason, every video I record with OBS on this latest version (I opened it up for the first time in a few months two weeks ago) is ONLY decoding with the CPU when opened in VLC. Of course, this makes playback choppy, blocky and terrible, even on a 3800x. I can't tell if it's of enough quality to move to Premiere.

The peculiar thing is, upon opening recordings I made in August of The Simpsons Hit and Run, those recordings work just fine in VLC - the GPU Decoder in my 1080 Ti is working properly, at about 35% utilization, with no stutter or playback issues to speak of. This reasonably rules out the 1080 Ti and its drivers as being the issue here. And again, this recording setup worked great at that time, doing exactly what I wanted it to do.

I have not changed a single setting of any kind since I made those recordings 2 months ago - NVENC HEVC, .mkv output, CQP 18. And yet, for every new recording, no matter if it's screen capture of this PC or external capture through my 4K60 Pro Mk. 2 - none of the inputs produce recordings that are decoding with the GPU.

What is the problem here? Did the OBS update do something I'm not seeing? Is there some sort of flag that I'm not checking, or is it a bug in the software?

I assume that this is an easily fixable issue. Anyone who may know, please give a shout.

Thanks in advance.


New Member
Well, I don't know why, but digging in the Codec Information got me something.

I switch between SDR and HDR recording settings - and use NV12 for SDR and P010 in HDR.

For some reason, the NV12 4:2:0 color space seems to be the problem. Although I'm warned against using P010 by OBS, using it in both cases now renders the video properly. Perhaps NVENC HEVC is somehow incompatible with NV12.

So, if you have this issue, change your color space to P010, whether you're using HDR or SDR. Videos will now decode properly with the GPU rather than the CPU.


Active Member
I don't have that issue, decoding on the 3090 with VLC v3.0.18. Recorded with OBS v29.1.3 Is your issue with v30RC1?



ID :1
Format :HEVC
Format/Info :High Efficiency Video Coding
Format profile :Main@L5@High
Duration :3 h 14 min
Bit rate :12.3 Mb/s
Width :3 840 pixels
Height :2 160 pixels
Display aspect ratio :16:9
Frame rate mode :Constant
Frame rate :30.000 FPS
Color space :YUV
Chroma subsampling :4:2:0
Bit depth :8 bits
Bits/(Pixel*Frame) :0.049
Stream size :16.7 GiB (83%)
Default :No
Forced :No
Color range :Limited
Color primaries :BT.709
Transfer characteristics :BT.709
Matrix coefficients :BT.709


ID :2
Format :PCM
Format settings :Little / Signed
Duration :3 h 14 min
Bit rate mode :Constant
Bit rate :2 304 kb/s
Channel(s) :2 channels
Sampling rate :48.0 kHz
Bit depth :24 bits
Stream size :3.13 GiB (15%)
Default :No
Forced :No
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