Question / Help H.264 Capture Card vs NVENC H.264

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ipkonfig

New Member
First, please keep from turning this into "you don't need a card / you'll degrade it more / that's dumb / makes your PC run slow......" These remarks have derailed several threads and provide nothing to the thread

I am curious for those out there like myself: what's really the difference between these two?

According to Nvidia's white page on their NVENC H.264 chip you can do 6K recording with around 30FPS. Ok, great, that's not really logical to my curiosity below:

the question -- So what is the benefit to having:

Capture card sitting in your PC doing all of the encoding for your stream
vs​
NVENC chip sitting inside your Nvidia Geforce card
+​
Regardless of the CPU in the PC (remove this from the factor and question)​

the 2nd question
Why are streamers, who are partnered with Twitch and or have a large following, building systems with multiple capture cards into an encoder PC? (answer this without web cams, layers, ect.)



What I'm not following is why doesn't every streamer, high followers or not, just use the NVENC H.264 chip for all of their streaming when Nvidia claims its possibilities are top notch on their tiny chip sitting in all of our video cards?

i.e. Is the Elgato HD60 Pro & the Avermeda Gamer Pro encoder H.264 chips better than the NVENC H.264
 
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Osiris

Active Member
A capture card will not be doing the encoding for your stream, OBS will. Using a capture card has no benefit in a single PC setup, all it will be doing is capturing the video/audio, which OBS will have to decode (when using USB 2.0 devices) and then encode again for the stream, I know there is also the Avermedia h264 encoder in OBS but it's not very good.

NVENC is just an encoder, but does not provide the same quality at the same bitrate as with x264 (encoding on CPU), that's why it's only recommended as a last resort for streaming. For recording it's perfectly fine, since you are not bitrate-constrained.

As for the second question, i've not seen streamers with multiple capture cards, could be several reasons like capturing a camera (DSLR for example) or maybe they have 2 consoles and want a capture card for each?
 
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vapeahoy

Member
I have 3 capture cards and am basically just a casual sometimes streamer (my obs name here has nothing to do with it).
I use one for capturing main desktop/game feed, one for a steady face cam and one for, uhm what was it.. oh ye action cam that i can use for f.ex keyboard cam. In addition i also have a normal c930e webcam, which is kinda pissy bcoz it only does 30 fps max and so it adds some flickering there. Should probably replace that one as well with a normal cam and add another capture, or put it behind a switch. But i really like the idea of not using a switch as it allows u to always switch directly to a video source in obs without also having to do a physical switch.

In the end if u dont go nuts like this it will be better and more "normal".Probably most people watch my stream have no idea whats going on half the time apart from the game capture feed. I dont blame them. I dont either.
Also dont get a dslr, just a regular video cam, cheap as u can find will do.

There is also another option to capture here which in my experience is the absolutely smoothest way to stream which is game capture on the game pc, sending the feed to the capture pc for encoding there. It's just many games can't be "game captured" in obs and so compability concerns.

Another option is using a networked heavy setup and rmtp everything. Which there's lots guides on.
 
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ipkonfig

New Member
@Osiris

What does the chips do then? So OBS ignores the processors on Nvidia and Capture cards and OBS is 100% a software encoder? I thought turning off x264 and using NVENC and other capture devices puts the encoding onto that chip and OBS does what it needs from there?

I see streamers using capture cards in encoder PCs all the time that is capturing the game (yes OBS runs on that encoder PC) but honestly OBS does nothing but software?
 
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Osiris

Active Member
OBS can use NVENC, I didn't say it couldn't. But NVENC has nothing to do with capture devices, it's a chip on your GPU, that OBS can use to encode the final image (the one you see in the preview)
Only USB 2.0 capture devices actually have a internal encoder, but they can't be used by OBS.
 
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ipkonfig

New Member
@Suslik V - article doesn't list Elgato HD60 Pro

@Osiris - I never mentioned the USB options, would never use those. I'm only talking about the PCIe version of the Elgato against the chip used in Nvidia's graphics cards, which is referred to in the market as an encoder chip (it even encoders movies). Technically all chips, such as Nvidia's, Elgato's, other brands and the CPU itself do the horsepower behind OBS. OBS just relies on the information its being fed from the processor. So all capture devices will do something - it's how much horsepower brand A is to brand B and that's what I'm trying to figure out here.

Everyone knows OBS and other software out there is the "give me food so I can give you a product" calculations. I want to know which chip can give one the best performance and quality without having to spend more money on another PC.
 
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DryRoastedLemon

Member
article doesn't list Elgato HD60 Pro
Click to expand...

Of course not. The HD60 Pro does nothing to aid encoding load.

x264, NVENC, QuickSync, and VCE exist completely separate from capture cards. Capture cards will not help you with the encoding load. The only thing they do is feed the visual data to OBS, which then does the encoding using either x264, QuickSync, NVENC or VCE.

Nvidia's graphics cards, which is referred to in the market as an encoder chip (it even encoders movies).
Click to expand...

Eh. It's an encoder. It stands to reason that the encoder can process video data. Doesn't mean it's efficient. The best compression method for bandwidth efficiency is CPU based x264 encoding. Don't forget that movies are encoded at bitrates that are completely unsuitable for livestreaming.
 
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vapeahoy

Member
Getting a good streaming setup is going to cost money no matter how you try and turn things around. I wouldnt worry about getting a capture card as much as getting a good graphics card to both game/encode with if you're just starting out.
I'd also like to light a candle for usb capture devices (usb 3+), seeing as you can always fit one in on something and not be required to have a free internal slot. With how obs works i never saw the point of internal ones, all mine are usb 3, works great.
 
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ipkonfig

New Member
Loving the accusations being made here by two of you already and one of you clearly showed you don't know what your talking about - but I avoided slamming that into the ground and rubbing any one's face into it. It's pointless.

I'm shaking my head because the point continually gets overlooked by two of you. But honestly that's not my fault. I'm just going to continue on.

I'm above the snarling remarks. I won't stoop to your levels. But do go on below. I won't be reading anything past my reply. You can watch the IP addresses coming back to this thread.

Off to the other forums - I had hopes that their mocking of those in the OBS forums were not true, sadly I should have listened.

Take care
 
Gol D. Ace

Gol D. Ace

Member
I have the feeling I shouldn't reply to this...
Well here we go anyways.

Technically all chips, such as Nvidia's, Elgato's, other brands and the CPU itself do the horsepower behind OBS. OBS just relies on the information its being fed from the processor. So all capture devices will do something - it's how much horsepower brand A is to brand B and that's what I'm trying to figure out here.
Click to expand...

By default OBS is using x264 a software encoder.
There is no "special chip" behind this. Just software and the power of your CPU.

Elgatos internal h264 stream cannot be used by OBS at all.
If you're using a Elgato device you have to use x264, NVENC, QSV or the avermedia encoder with it.

OBS would have to feed the data back to the Elgato, let it do processing, get the data back and send it out.
This is not supported for Elgato devices.
Elgato Capture Cards are not having any benefits at all in this case.

The only capture cards that benefit less CPU usage are capture cards that have the avermedia encoder.

Having a NVENC chip and using it for encoding will reduce CPU load.
But it will also require much higher bitrate for reaching the same quality as x264.

The same with QSV and enc-amf. They're not as efficient in terms of quality to bitrate as x264 (Software Encoder).

=

Pro Less CPU usage
Contra Worse quality with the same bitrate compared to x264 (Sofware Encoder)


-----------------

Capture card sitting in your PC doing all of the encoding for your stream

The only capture card sitting in your PC doing all the encoding for your stream would be the avermedia cards that got mentioned.

Pro: Less CPU usage
Contra: Worse quality with the same bitrate compared to x264 (Software Encoder)

---

NVENC chip sitting inside your Nvidia Geforce card

Pro: Less CPU usage
Contra: Worse quality with the same bitrate compared to x264

What I'm not following is why doesn't every streamer, high followers or not, just use the NVENC H.264 chip for all of their streaming when Nvidia claims its possibilities are top notch on their tiny chip sitting in all of our video cards?
Click to expand...

Because the quality is worse with the bitrates you can use for live streaming.
 
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