Which Capture Card should I get for streaming or recording? And do I need one?

I want to start today's Guide with a few questions:
Why do you want to get a Capture Card? Do you want to capture a console? Skip the next questions and read the next paragraph, else read on. If you answered the last question with no, do you plan on using the Capture Card in a two-PC setup? If you answered this question with yes, skip to the next paragraph. If you answered the question with no:

• a Capture Card gives no significant performance boost anymore, compared to traditional capture methods
• a Capture Card can be used to circumvent problems of such traditional capture methods
• a Capture Card can increase the load on your system compared to traditional capture methods
• actual Hardware Encoders capabilities are inferior to CPU encoding techniques -] not designed for live streaming, only recording

Now if you still want or need a capture card lets get right on it. Selecting the best available capture card for your purpose can be a big hassle if you do not know what you have to look for. We already saw there can be several reasons why you want to use a capture card, but all of these reasons have one question in common.

• What Outputs does my Source I want to capture offer, and do I need to split or can I "clone/double" the Output to two different ports?

First things first, if you only have one Output available, for example on an older console, you might want to make sure you get a capture card with pass-through and if this is no option you can take a look at getting a video splitter.
Pass-through means your capture card offers the same kind of Inputs as an Output to attach a Monitor/TV "after" the capture card. Normally this pass-through should not interfere with the signal so you should get no delay or color difference. The reality can look different though and some capture cards have reported delays/color distortions when using this option. In this case a splitter would be a good choice. Lets get back to the output you want to capture:

• Consoles
  • HDMI / RCA / SCART / Composite / RGB
• Computer
  • HDM / VGA / DVI / DP / (older PCs might have S-VHS/Composite)
• Cameras / Webcams
  • HDMI / FireWire / RCA / probably others

As you can see, in some cases a capture card with HDMI input would allow you to capture several different Sources using a switch or switching cables the old style. But in reality the PS3 for example protects its HDMI content which makes it hard to record with most capture cards. The PS3 normally also offers RGB/RCA output so this would be the way to go then.

Now that we know what Input our capture card should offer, we have to make sure the capture card will be able to "read" our Output from our Source.

• old Consoles
  • Progressive: 256 × 224, 256 × 240, 512 × 224, 256 × 239, 512 × 239
  • Interlaced: 512 × 448, 512 × 478
• current gen Consoles
  • Progressive: 1280 × 720, 1920 × 1080(rarely)
  • Interlaced formats are supported but not recommended
• coming Consoles
  • Progressive: 1280 × 720(will still be used), 1920 × 1080(more often), maybe 4K
  • Interlaced formats are supported but not recommended
• Computer
  • Progressive: all kinds of resolutions, 720p/1080p preferred
  • Interlaced formats are supported but not recommended
• Cameras
  • Different Formats depending on your Model, Aspect Ratio, etc.

As you can see, this makes things a bit more complex. I also want to mention a special thing you have to be aware of with all capture cards below the 500$ range. You cannot capture 1080p 60fps footage at 60fps with a USB/PCI-E x1 or even Thunderbolt device (currently available). The Avermedia Live Gamer HD is the only card I currently know of that supports downscaling this footage to 720p while keeping 60fps. Still if you want to record/stream on 1080p you will only get 30fps as the bandwidth seems to be not sufficient for full 1080p 60fps output of the card over PCI-E x1 slots. For the Hardcore User, Kona/Datapath/BlackMagic all offer more powerful capture cards which can Input up to 2K/4K resolutions. The prices vary between 800-2000$.

Some cards also report to take 1080p 60fps input and output it as 1080p 30fps, while in reality they convert it to a interlaced signal, which often reduces the quality by quite some margin. Check reviews or ask people that use your desired device to make sure this is not the case. In my capture card comparison list I tried to add these info as exactly as I could gather them on the manufacturers homepages. As mentioned earlier, a few capture cards also offer a hardware encoder which can in certain scenarios reduce your CPU usage while recording to zero. The downside of these encoders is their need for a higher bitrate to achieve the same quality a CPU encoding would reach. So they can be used for local recordings in which bitrate and bandwidth is no problem while for live streaming you would want to use your CPU.

At this point we know what ports our capture card needs and what resolutions it has to support. With the ports we normally also secured that we can receive audio of our Source with the capture card. In some cases it can be needed to differ from the usual setup, but its hard to keep every possible setup covered with this guide. If you have questions, just post them below. So last but not least we have to make sure we have an available PCI-E slot, or a free USB port to connect our new device. Again, check reviews of the device, talk to someone that uses it, check the forums of the streaming/recording tool you want to use with it for known problems, make sure you can return it if its not what you wanted and ask someone with knowledge before changing hardware if you have never done this before.

Feedback, criticism, comments are always welcome.

Edit (2014/08/11): Unless you want to capture a Camera or Console:

R1CH said:

There's no point using a capture card on a single PC. The only possible use is to capture the entire screen when circumstances don't allow otherwise (eg capturing a game which is highly incompatible with hooks)

Single PC with game capture:
GPU Output -> GPU -> GPU Render -> System Memory -> Encode -> Stream

Single PC with capture card:
GPU Output -> Capture Card -> PCI Bus -> System Memory -> GPU -> GPU Render -> System Memory -> Encode -> Stream

Dual PC with capture card:
PC1 (Gaming): GPU Output -> Capture Card
PC2 (Encoding): PCI Bus -> System Memory -> GPU -> GPU Render -> System Memory -> Encode -> Stream

As you can see, with the dual PC setup, you offload a lot of the work onto the 2nd PC, so it provides a large CPU reduction on the PC you're gaming on. This is the only situation in which a capture card makes sense for PC games.

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