Question / Help PCI Capture card/ video pass-through device for a stand alone streaming pc

[Muchbroadcast87]

Hello OBS community!

Im looking for someone who knows his way around PCI capture cards (HDMI inputs)

Basically im building me a pc that will do only one job - live streaming

here is the build:
Case: Zalman T1 Plus Mini-Tower USB 3.0 (23€)
MOBA: ASRock Z97 Pro3, Intel Z97 Mainboard - Sockel 1150 (95€)
CPU: 4790k (300€)
Cooler: Cooler Master Hyper 412S (33€)
PSU: be quiet! Pure Power L8 modular 430w (63€)
RAM: HyperX Impact Series SO-DIMM LV DDR3-1600, CL9 - 4 GB 1.35v (45€)
GPU; will be using my old 7850 radeon

Now i need to decide on a good capture card which can pass through an uncompressed high quality 1080p/60fps video from my gaming PC to OBS on my streaming PC. So far i narrowed it down to Live gamer HD lite and blackmagic pro.

Are there more good options out there? I know that the cards Ive mentioned come with build in encoder however that's useless to me since 4790k will be doing all of the encoding in OBS.

So im looking for a pass through device which can simply transfer uncompressed video from one pc to another. What other options do i have here?


1 additional question about audio:

So i will connect my usb mic to the streaming pc no problem there...however what about the ingame sound can gtx970 transfer sound over hdmi to the capture card for OBS to use?

 

[Sapiens]

The Live Gamer HD will output 1080p30 or 720p60 with color space conversion and Blackmagic devices have unreliable drivers. Streaming at 1080p60 is also generally a waste of resources due to bandwidth restrictions and Flash player performance, so something like the LGHD would still be a good choice should you decide to stream at more reasonable settings. If not you'll probably want to look at importing a Micomsoft XCAPTURE-1 (external USB 3.0) or SC-512N1-L/DVI (internal PCIe) from Solaris Japan, or something like a Datapath card from eBay.

A similar thread from yesterday covers this in more detail - https://obsproject.com/forum/threads/real-1080p-60fps-capture-card.20523/

 

[Muchbroadcast87]

The Live Gamer HD will output 1080p30 or 720p60 with color space conversion and Blackmagic devices have unreliable drivers. Streaming at 1080p60 is also generally a waste of resources due to bandwidth restrictions and Flash player performance, so something like the LGHD would still be a good choice should you decide to stream at more reasonable settings. If not you'll probably want to look at importing a Micomsoft XCAPTURE-1 (external USB 3.0) or SC-512N1-L/DVI (internal PCIe) from Solaris Japan, or something like a Datapath card from eBay.

A similar thread from yesterday covers this in more detail - https://obsproject.com/forum/threads/real-1080p-60fps-capture-card.20523/

Thank you for your reply!

SC-512N1-L/DVI sounds like a good card but importing from japan (250€+shipping) not an option for me atm....

I'm pretty curious as to why is it so hard for a capture card like LGHD to simply pass through a signal without changing something on its quality....

 

[Sapiens]

In part because it requires more bandwidth than is available to a PCIe 1x card. Full 1920x1080 at 60 FPS and RGB32 needs a bit more than even PCIe 4x provides; until recently cards like that were limited to the professional realm and cost quite a bit of money. Cards like the Datapath VisionRGB-E2 you see on eBay once in a while retail for $1500+.

 

[Muchbroadcast87]

In part because it requires more bandwidth than is available to a PCIe 1x card. Full 1920x1080 at 60 FPS and RGB32 needs a bit more than even PCIe 4x provides; until recently cards like that were limited to the professional realm and cost quite a bit of money. Cards like the Datapath VisionRGB-E2 you see on eBay once in a while retail for $1500+.

Ah... so its all about bandwidth...well that explains alot!

I did some reading and found out that PCI-E has speeds of 250MB/s where USB3.0 has 625 MB/s. So extreme cap U3 should have two times better quality on pass through? Or am I not getting something? Is there a downside to getting USB 3.0 capture card?

 

[dodgepong]

I think you're misusing the term "passthrough". Passthrough usually refers to taking the raw input signal and passing it through to an output so that the signal can be input into a TV or something like that. It's like putting a splitter before the capture card, and sending one end to the TV and one end to the capture card so that one signal doesn't get touched.

Higher bandwidth does not affect quality directly, necessarily. High bandwidth allows for raw video data to be sent uncompressed/unencoded, but if you have enough bandwidth for raw video (like PCIe and USB 3.0) then it doesn't matter how much more bandwidth one has over another. Also, you're quoting PCIe 1.0 speeds, which are much slower than modern PCIe 3.0 busses. So no, the U3 wouldn't be higher quality than a PCI card, since high bandwidth does not directly have anything to do with quality.

I have never used a U3, but I've heard it can have some hitching problems. I would much sooner trust a Micomsoft card, personally.