The best stream configuration for streamers

In this article, we will focus on learning about configuration streamto find the best parameters for an effective balance between quality and smoothness, and each encoder mode affects the results. stream how.

Before we start… one of the most important things we want to know is better software encoder on CPU or hardware on GPU. This is one of the important controversies, because if encoding with GPU is the way to go, then the configuration you need stream It doesn’t matter what is on the CPU. But if, on the contrary, the CPU encodes better, then of course your choice of CPU will play a role in the quality of the code. stream and even in the game.

Over the past few months, GPU encoder has gradually become more attractive as Nvidia has upgraded their encoder engine in a new GPU architecture, Turing.

While a lot of people focus on improving HEVC compatibility and performance – which is not really important to stream current game – the new Turing engine will improve H.264 by 15% over the old Pascal engine (GTX 10 series). So this is what we’re aiming for, too, to see how Turing confronts x264 encoder software.

As for the GPU, we’ll be using the RTX 2080 Turing encoder, and the Titan X Pascal for Pascal Encode, and we’ll see how AMD stacks up with the Vega 64.

The second lesson includes software encoding with x264, with many different presets (configurations). We’ll cover CPU comparisons when using encoding software in another post, where we’ll see how each preset affects quality and smoothness.

All tests use Core i7-8700K overclocked to 4.9 GHz and 16GB DDR4-3000 RAM, recommended configuration for high-end gaming. In the future, we should see the 9900K alongside AMD’s Ryzen CPUs.

Regarding the streaming software, we will use the latest OBS, configurable 1080p 60 FPS with a bitrate of 6000 kbps. This is the maximum recommended configuration on Twitch. If you just want to return to gameplay for other purposes, you should push the bitrate higher, but with Twitch, you only need to keep it at 6Mbps or lower.

The article will test two games: Assassin’s Creed Odyssey requires high GPU and CPU, this is what CPU encoding often has difficulty; and Forza Horizon 4, require less CPU but because of the fast process, low bitrate encoding can be problematic.

We’ll start with GPU encoding. Let’s see if Turing is much of an improvement over the old GPU encoder – Pascal is almost incomparable to CPU encoder.

With Nvidia cards, the article uses NVENC in OBS, and sets the preset to High Quality at 6 Mbps. OBS has a few other options but High Quality, as the name suggests, produces the highest quality. With AMD Vega 64, we have several encoder options, both in terms of presets and birates, but with no satisfactory results.

When comparing Turing and Pascal’s NVENC, there’s really no difference at 6 Mbps. Both are affected by ‘clump’, in general the image lacks detail. Specifically Forze Horizon 4, the clumps are very visible on the road and look very bad. Turing’s encode seems sharper and, in some situations, less cluttered, but the two aren’t pretty overall. And if you want stream game, this is certainly not the quality that will impress viewers.

AMD’s encoding is even worse when the GPU is used almost 100%. The software can’t render more than 1 frame per second – but with Nvidia cards that shouldn’t be a problem.

If using the ‘frame limiter’, the GPU is only used 60% in Forza Horizon 4 and even with the encode preset set to ‘Quality’, the Vega 64’s quality is still worse than Nvidia’s Pascal cards.

So AMD is out of the race, let’s see how Nvidia’s NVENC stacks up against x264 software encoders on CPUs. In the Assassin’s Creed Oyssey benchmark of slow scenes, NVENC even using the High Quality preset was still inferior to x264’s veryfast preset, in terms of image detail, although both were limited to 6 Mbps.

Veryfast x264 isn’t impressive, but when compared to Turing’s NVENC, it’s truly superior.

In the Forza Horizon 4 benchmark in fast scenes, Turing’s NVENC outperformed x264 veryfast in several areas, NVENC once again struggled a bit due to ‘clump’ while veryfast had problems with moving details. With speeds like that in the game, NVENC is almost on par with x264’s ‘faster’ preset. However, x264’s ‘fast’ preset is much better than NVENC’s in fast movement, and completely outclasses the opponent when the game moves slowly or stops altogether.

The above results are somewhat surprising because Nvidia previously said that the new Turing NVENC engine to encode H.264 is equivalent to x264 in the ‘fast’ preset or slightly faster at 6000 Kbps with a 1080p 60 FPS stream. But from what we observe, especially in Assassin’s Creed Odyssey, the encoding software is still better.

Preset ‘fast’ is the lowest configuration you should consider if you want stream quality, if you value image quality with viewers. It is superior in quality to faster.

Medium once again improves, but the gap between fast and medium is smaller than between faster and fast. It is very difficult to achieve the medium preset on the hardware that the computer is using. The article also tried the ‘slow’ preset but the computer couldn’t afford it.

As for fast motion in Forza Horizon, the article completely recommends against using the ‘veryfast’ preset because it is worse than NVENC in this range. Unfortunately, the 6000 kpbs limit prevents the quality of the preset from being more visible, but medium is much better than fast.

The ‘faster’ preset also looks bad so for games like this it’s best to keep it medium. Unfortunately, Twitch has a limit of 6 Mbps.

Smoothness

Image quality is only one aspect, the other is smoothness. You need to ensure that your gaming experience as well as the smoothness of the stream are not affected.

Let’s take a look at GPU encoding and see how it affects:

Pascal or Turing’s NVENC doesn’t affect framerate much, only 10-20% depending on the game, in other words, you’ll get around 10-20% frame drops when recording with NVENC, compared to just playing game.

The good news is that, even though you run the game at a lower frame rate when NVENC is running, stream still has perfect smoothness, no frame drops, even if the game is using 100% GPU. AMD’s encoder engine doesn’t affect game frames much, but it drops 90% of frames when the GPU is overused, rendering AMD almost useless, as discussed above.

The smoothness of the encoding software depends on the game you play. In Assassin’s Creed Odyssey, the game uses both CPU and GPU: stream CPU usage will have a noticeable effect on frames, and the High Quality preset has a hard time keeping up with the game.

With Core i7-8700K and RTX 2080, when playing Odyssey with the custom preset, we can only encode the game using the ‘veryfast’ x264 preset without dropping frames in stream. X264 veryfast also reduces frames by 17%, much lower than NVENC. Encode veryfast looks better than NVENC in this game, so the trade-off is well worth it.

However, the ‘faster’ preset started seeing frame drops on stream. 8.5% off, stream jerky and difficult to track. Meanwhile, the smoothness in the game decreased from 90 FPS average, to 63 FPS with only 1% higher than 30 FPS. Obviously this preset makes it impossible for the computer to handle. However, the smoothness of the game is slightly better in these presets than in ‘faster’, but that may be because the encoding software takes up more resources, only allowing the game to use a bit of CPU.

One way to improve the smoothness of the game is to limit the game to 60 FPS, by those watching stream can only watch up to 60 FPS. Even with the limit, things don’t get much better: the ‘fast’ preset reduces the frame rate by 9%, while the ‘faster’ does not reduce the frame, but has a 1% chance of dropping the frame to 40 FPS. The only option is to use ‘fast’ to reduce the image quality and try again, but this article is not intended to optimize the Assassin’s Creed stream.

With the 8700K restricted to streaming at veryfast, let’s see how other CPUs perform in part 2 of this article. But it’s clear that the 8700K – a popular high-end CPU for gaming – is often used for streaming. Lower CPUs, specifically with fewer cores, will have to run the ‘veryfast’ preset more often.

As for Forza Horizon 4, the game uses less CPU, so the CPU-based encoding software produces a smoother game than the GPU-based encoding hardware. Obviously, the software can make more use of the CPU to streamwithout affecting the GPU.

Using the x264 preset affects the smoothness of the game by 6%, but the difference between veryfast and fast is only a 5% reduction, even though the CPU has to use a lot in the ‘fast’ preset.

About streamwe don’t see the frame drop in both veryfast and faster, however, when we switch to fast, the framerate drops by 12% in stream. Stream become jerky and difficult to track. However, since the game is running at close to 120 FPS, we can limit it to 60 FPS to reduce the pressure on the CPU. With a limit of 60 FPS, the ‘fast’ preset can be used without the upper frame dropping stream. That limitation also paves the way for choice stream preset ‘medium’, however with 8700K we see all frames drop 2% with 60FPS limit, though not ideal. If we want to encode ‘medium’, we have to reduce the CPU pressure in the game by reducing the game’s configuration.

SUMMARY (Will continue in part 2)

With all of the above experiments, here is a summary of what we have learned. For those who are considering buying a current graphics card, the Turing engine for H.264 is not really much of an improvement over Pascal and obviously, stream by GPU is still not the optimal choice.

You should only use NVENC in fast games, where the CPU encoder system cannot achieve the x264 ‘faster’ preset or better. Games with less movement should use the verfast x264 preset instead of NVENC, and veryfast is achievable with the vast majority of computers. stream (ie the purpose of installing the machine to stream).

Regarding AMD, their encoding engine needs to change more. It cannot operate when the GPU is running too much, even if it does, the quality is poor.

CPU encode is obviously more difficult, because you have to determine how much x264 encode the machine can handle (more specifically: what game your PC can stand). With the 8700K system, we’re stuck with ‘veryfast’ encode in CPU-intensive games – or run the ‘fast’ preset, sometimes ‘medium’ when limiting the game to 60FPS, making the CPU less overloaded. than.

But what streamers should aim for is to use the ‘fast’ preset, which is a preset that has nice picture quality at 6 Mbps on Twitch streams, and while it’s not ideal for high-speed games, fast is better than faster or better. veryfast a lot. Medium is also worth a try on high-end computers, but it’s best to ignore what the ‘slower’ preset does.

Gaming and stream on the same computer is fine, but it should only apply if you’re a part-time or recreational streamer. For professional or full-time streamers, they should use a second computer dedicated only to stream, good CPU usage and capture card. This will reduce the encoding load, allowing you to stream ‘preset’ or ‘slower’ comfortably with the best streaming quality without affecting the quality of the game.

Part two of this article will learn which CPUs can encode in the above presets.

Source: techspot