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Table of Contents

• Intro/Overview
• Decode Mode Support
• Notes on RGB Color Space
• Format Support
• Notes on Scaler Support
• Input Latency Testing
• Notes on “Bitrate” support
• Testing Methodology
• Limitations & Future Improvement
• How to submit capture cards for testing

Intro/Overview

IN THIS RESOURCE: I will provide extensive documentation about the connection types, supported decode modes, supported resolutions, frame rates, passthrough, and input latency (to preview) of every capture card I have access to.

This will be an evolving project - I will be testing every capture card I can get my hands on moving forward and updating this guide along the way, potentially for years to come. I only have access to so many capture cards at this exact moment, but I’m constantly reviewing more, and am trying to test as many as possible. Have a capture card you want me to test? Check out the last section in this guide.

I have posted a breakdown/walkthrough of this Resource to my YouTube channel - this explains each of the charts, some of my reasoning and thinking process, etc. Keep in mind that this is simply a snapshot of things at the time of posting, whereas this Resource page will remain updated.

[For those interested in the raw data (which will be updated sooner than this Resource) you can view my Google Sheets workbook (multiple sheets) here.]

Decode Mode Support

Some buyers are looking for capture cards that provide specific decode modes to the user. These are color compression formats (not to be confused with data compression) that affect the bandwidth required by the video feed through the device, as well as the total image quality.
Common decode modes include:

• YUY2 - 4:2:2 color space, uncompressed data stream
  • This is the most common, and generally the target you want to aim for
  • Requires more bandwidth over USB/PCIe bus, but has minimal system resource load and latency
• MJPEG - Compressed data stream, can be 4:2:0, 4:4:4, or 4:2:2
  • Literally “Motion JPEG” - it’s JPEG (like the photos) image compression
  • Lower bandwidth over USB/PCIe bus, but requires your CPU to decode the stream before re-encoding on your OBS canvas. Increases system resource load and latency.
  • Usually through UVC protocols, MJPEG is 4:2:2
• YV12/NV12 - 4:2:0 color space, uncompressed data stream
  • Elgato’s preferred decode mode
  • Requires less bandwidth over USB/PCIe bus than YUY2 (more than MJPEG), should have less system resource impact as well - unless OBS is set to RGB mode or something (in advanced settings)
• RGB (XRGB) - 4:4:4 completely uncompressed color and data stream
  • Much less common
  • Best possible quality image, improves scaling and final encode quality
  • Uses much more bandwidth than any other mode

CAPTURE CARD	MAX RESOLUTION & REFRESH RATE	DECODE MODES SUPPORTED
CA Flint 4KP	1080p60	MJPG, YUY2
Magewell 4K Pro Capture HDMI Plus LT	4K60 / 1440p144	XRGB, I420, NV12, YV12, YUY2, UYVY
Elgato 4K60 Pro	4K60 / 1440p144	YV12/NV12 (up to 2160p60), YUY2 (up to 1080p60)
AVerMedia Live Gamer 4K	4K60 / 1440p144	XRGB NV12 YUY2 (all modes), P010 (HDR)

Here are the supported (and functional) decode modes exposed to OBS Studio from the capture cards I have tested. Do note that the native applications respective to specific capture cards may only allow or utilize one of these modes.

The “UYVY” mode is essentially the exact same as YUY2. It’s 4:2:2 and etc.
“P010” is a compressed color mode for HDR encoding from HDR-compatible capture cards (namely from AVerMedia).
Any capture card (such as the original Elgato Game Capture HD) that shows a “h264” decode mode is likely exposing the on-board encoder’s feed from the card and is going to take even more work from your CPU to decode prior to encoding, cause even more latency, etc. It is not recommended to use these modes. (And no, this will not allow you encode your OBS stream using the capture card’s encoder. There’s a specific plugin for this integrated for only the original AVerMedia Live Gamer HD, but does not apply to anything else.)

(Information on YUV/etc. color spaces: 1, 2, 3)

Also I wanted to point out that current drivers for Elgato capture cards may show XRGB/RGB modes in OBS Studio - however these are not real. They’re emulated (or simulated?) from the 4:2:0 color space that those devices primarily operate in. Using them may result in a solid color screen, washed out view, or just add more resource load to your system as the driver is taking the 4:2:0 color feed and converting it to the emulated RGB mode and then OBS has to convert it back to NV12 for your stream. Elgato does not recommend using these modes and neither do I.

Notes on RGB Color Space

Full 4:4:4 RGB support in general is pretty rare to encounter on capture cards in general - both due to cost and to bandwidth requirements. Typically this is reserved for the very expensive and high end cards from the likes of Magewell, BlackMagic Design, and AJA. However, the AVerMedia Live Gamer 4K offers RGB decode modes throughout, and the Live Gamer Ultra offers it for 1080p60 as well!

While OBS typically operates in the 4:2:0 color space (and that’s all that Nvidia’s NVENC is capable of with the new shared texture implementation as of OBS v23) for streaming purposes - though you can set it to 4:4:4 RGB for recording modes - having a 4:4:4 RGB uncompressed signal still gives you the best results as a source, as you have more information to work with when downscaling, downsampling, and compressing. Garbage in, garbage out!

Format Support

Here’s the overall chart with specific resolution and framerate support (just the max specs listed for now), whether or not HDR is supported, etc. and the actual connection types for each capture card. I tried to specify if there’s a difference between the accepted input/passthrough resolution and framerate and the actual capture framerate. I’ll try to go back through and be more verbose about these details when I have time.

As noted in my review, the ClonerAlliance Flint 4KP capture card has the potential to be used for 1440p60 - however I ran into glitching with it. Perhaps it might be more stable for others.

Notes on Scaler Support

I have noted in the above chart also when resolution and frame rate scaling is supported by the card. There’s two ways to do this - on the card or in the driver. If neither support exists (such as with the Elgato Cam Link cards) then the only option is to manually scale your frame in the OBS canvas window.
As far as I’ve been able to tell (and from asking around in the OBS Discord), there’s no significant or measurable performance impact between scaling it in driver vs on the OBS canvas - however this has been a big concern overall for vMix users specifically, so I’m mentioning it as-is for now.
In the future, as I confirm with manufacturers, I will differentiate between scaling done on-hardware (reduces bandwidth) vs in-driver. I do know for now that virtually all BlackMagic Design, AJA, Epiphan, and Magewell devices have hardware scalers, whereas Elgato’s is done in driver. My guess is that AVerMedia’s is done in driver as well, but I cannot confirm that yet.

Input Latency Testing

This is the big thing I actually started this project in order to test, so it will be my main focus of this documentation. I wanted to track the input latency from HDMI input to Preview in software (OBS and native apps for the specific devices) and see what that data told me.
While this is information that can vary over time and per individual setup - I think it provides an interesting image as to which capture cards are the fastest, and which you might have syncing problems with.
A goal of this project was to be able to provide relatively accurate latency numbers to suggest for setting up delays in OBS in order to sync up your webcam, audio, etc. with your gameplay - but given that these measurements are not static and can change per PC, I’m not sure that’s a great idea. Use this information as you will.

I also began testing to confirm that each capture card truly had realtime (no lag) passthrough on their HDMI feeds. This is not noted visually, as I did not encounter any situation in which this wasn’t the case, but I’ll be sure to update if that changes.

Here’s the latency numbers for all capture cards I have tested thus far, in OBS Studio 23.0.2:

Taking off the original Elgato Game Capture HD (which has obscenely high latency that can vary anywhere from a few hundred miliseconds to multiple seconds, this gives you an easier view of the average latency I encountered:

The fastest capture cards within OBS are of no surprise - mostly the high end ones. Though the generic Mokose U70S was a surprise on this list.
Of great surprise here was the BirdDog Studio NDI. This is a NDI (network IP video protocol) encoder/decoder box, so you’d think sending the feed via HDMI into the BirdDog Studio and then over the network to OBS via the NDI plugin would add a lot of latency but…. This thing makes it into the top 10 fastest capture devices by a long shot… impressive and confusing.

Other than the original Elgato Game Capture HD - which is absurdly slow (it and the non-S HD60 have very high latency due to running everything through the on-board H264 compressor, though the HD60 seems to only struggle in slowness in Elgato’s Game Capture apps, not OBS) - there’s not a significant delta (difference) between the fastest capture cards and the slowest - only about 30 to 40ms total range, which is interesting to note.

Other Heading

I also tested to see how input latency in OBS with these devices fared against the native desktop capture applications (where applicable) - such as Elgato’s Game Capture and 4K Capture Utility apps, and AVerMedia’s RECentral. Here you see where the Elgato HD60 becomes the highest latency capture card by a long shot in Elgato Game Capture.
*NOTE: My “Native App” data for BlackMagic DeckLink Mini Recorder 4K is somewhat inaccurate, as this measurement needs to be taken at a specific point at the bottom of the screen, and I could not figure out how to full-screen the preview in BlackMagic Media Express, so the measurement was taken closer to the middle of the screen.

AVerMedia’s RECentral (tested version v4.3.0.34 (Beta)) has latency fairly close to OBS Studio’s, actually beating it with all capture cards except the ExtremeCap UVC. However, this is something that kept counting up over time and may slow while capturing.