Home Software Game Streaming Investigation: Which Quality Settings Are Best?

Game Streaming Investigation: Which Quality Settings Are Best?

This is the primary a part of an investigation into sport streaming, a subject that we have been requested on earlier than — significantly after we overview CPUs — however that has purposely been omitted as a result of it’s fairly complicated to discover all of the nitty gritty particulars of streaming together with every part else in these evaluations.

In the subsequent weeks we’ll dedicate a few articles to sport streaming and give you a definitive reply on what kind of setup is the very best, and what high quality settings take advantage of sense to make use of. Today’s investigation is targeted on streaming high quality settings, we need to discover out what encoding settings ship the very best stability between high quality and efficiency, and the way every of the varied widespread encoding modes differs when it comes to outcomes.

One of the important thing issues we need to work out first: whether or not software program encoding on the CPU, or {hardware} accelerated encoding on the GPU is the higher method…

A little bit of backstory on our take a look at platform earlier than we get into the outcomes… one of many key issues we need to work out first, is whether or not software program encoding on the CPU, or {hardware} accelerated encoding on the GPU is the higher method. This is absolutely one of many key battles, as a result of if GPU encoding is the way in which to go, what CPU you want for streaming turns into largely irrelevant, whereas if CPU encoding is healthier, naturally your alternative of processor turns into a significant factor within the degree of high quality, not simply when it comes to consistency of streaming, however sport efficiency in your finish.

Over the previous couple of months specifically, GPU encoding has turn into extra attention-grabbing as a result of Nvidia up to date their {hardware} encoding engine of their new GPU structure, Turing.

While numerous the main focus went into bettering HEVC compatibility and efficiency, which isn’t actually related for sport streaming for the time being, Turing’s new engine can also be purported to carry 15% higher H.264 high quality in comparison with the older engine in Pascal (GTX 10 sequence). So that’s one thing we’ll look into, and see how Turing stacks up towards x264 software program encoding.

On the GPU aspect, we’ll be utilizing the RTX 2080 for Turing encoding, a Titan X Pascal for Pascal encoding, and we’ll additionally see how AMD stacks up with Vega 64.

The second a part of the investigation includes software program encoding with x264, utilizing quite a lot of presets. We’re going to go away a CPU comparability with software program encoding for a separate article, on this one we’re extra occupied with how every preset impacts efficiency and high quality.

All testing was carried out with the Core i7-8700Okay overclocked to 4.9 GHz and 16 GB of DDR4-3000 reminiscence, which is our present advisable platform for high-end gaming. In the long run we’ll see how the 9900Okay fares together with AMD Ryzen CPUs.

For capturing this footage we’re utilizing the newest model of OBS, set to document at 1080p 60 FPS with a continuing bitrate of 6000 kbps. These are the utmost advisable high quality settings for Twitch, in case you have been simply recording gameplay for different functions we’d advocate utilizing a better bitrate, however for streaming to Twitch you’ll must preserve it to six Mbps or decrease except you’re a Partner.

We’re testing with two video games right here, we’ve got Assassin’s Creed Odyssey which is a extremely GPU and CPU demanding title, one thing that CPU encoding struggles with; and Forza Horizon 4, which is much less CPU demanding however a quick paced title that low bitrate encoding can have points with. Both titles current a little bit of a worse case state of affairs for sport streaming, however in several and distinctive methods.

We’ll begin with GPU encoding, as a result of that is one thing that has been identified to be fairly horrible for a very long time now. The key little bit of curiosity right here is to see how Turing has managed to enhance issues in comparison with previous GPU encoding choices, which have been just about unusable subsequent to CPU encoding choices.

For Nvidia playing cards we used the NVENC possibility in OBS, and set it to make use of the High Quality preset at 6 Mbps. There are a couple of different preset choices however High Quality produces, because the title suggests, the very best high quality output. For AMD’s Vega 64 we tried a variety of encoding choices, each when it comes to preset and bitrate, with out a lot luck as you’ll see within the comparisons shortly.

Putting Turing and Pascal’s NVENC implementations aspect by aspect, there actually isn’t that a lot of a distinction at 6 Mbps. Both endure from severe macroblocking results, and on the whole there’s a full lack of element to the picture. In Forza Horizon Four specifically, blocking could be very noticeable on the street and appears horrible. Turing’s encoder is maybe a bit of sharper and in some conditions is much less blocky, however actually each are rubbish and if you wish to stream video games, this isn’t the form of high quality that can impress your viewers.

AMD’s encoder is even worse in that when your GPU utilization is up close to 100%, the encoder fully craps its dacks and might’t render greater than about 1 body per second, which wasn’t a problem with the Nvidia playing cards.

I used to be in a position to get the encoder working with a body limiter enabled, which introduced GPU utilization right down to round 60% in Forza Horizon 4, however even with the ‘Quality’ encoding preset, the standard Vega 64 produced was worse than with even Nvidia’s Pascal playing cards.

With AMD’s encoder out of the query proper from the start, let’s take a look at how Nvidia’s NVENC compares to software program x264 encoded on the CPU. In the slower transferring Assassin’s Creed Odyssey benchmark, NVENC even utilizing the High Quality preset is noticeably worse than x264’s veryfast preset, significantly for wonderful element, even when each are restricted to simply 6 Mbps.

Veryfast x264 isn’t superb by any stretch, however the degree of blocking and the dearth of element to Turing’s NVENC implementation is horrible compared.

In the quicker transferring Forza Horizon Four benchmark, Turing’s NVENC does outperform x264 veryfast in some areas, NVENC once more most likely has barely worse blocking however veryfast actually struggles with transferring wonderful element. With this degree of movement, NVENC is roughly equal to x264’s “faster” preset. There is little question, nevertheless, that x264’s “fast” preset is considerably higher than NVENC in quick movement, and fully smokes it when there may be sluggish or no movement.

These outcomes are maybe a bit of stunning contemplating Nvidia claims their new Turing NVENC engine for H.264 encoding is across the mark of x264 quick encoding and even barely higher at 6000 Kbps for 1080p 60 FPS streaming. But from what I noticed, particularly in Assassin’s Creed Odyssey, software program encoding was significantly better.

When trying purely at software program x264 encoding presets, there are noticeable variations between every of veryfast, quicker, quick and medium. In the slower transferring Assassin’s Creed Odyssey – and ignoring the clear efficiency points with some presets for now – veryfast and quicker don’t ship a fantastic degree of high quality, with numerous smearing, blocking in some areas, and a scarcity of wonderful element significantly for objects in movement.

These two presets actually must be reserved only for people who need to stream casually, as a result of the presentation when capped to six Mbps isn’t nice.

The quick preset is the minimal I’d think about using for a top quality sport stream, significantly in case you worth picture high quality in your viewers. It gives a noticeable high quality soar over quicker, to the purpose the place blurred wonderful element now has definition.

Medium is a noticeable enchancment once more, however the hole between quick and medium is smaller than the hole between quicker and quick. And as we’ll see in a second, good luck utilizing the medium preset on the identical system the sport is operating on. I did additionally take a look at the sluggish preset however at this level we’re into diminishing returns for a large efficiency hit.

For quicker movement in Forza Horizon 4, once more I’d fully dismiss the veryfast preset instantly as a result of it’s worse than NVENC for any such content material. Unfortunately the tight bitrate restrict of 6000 kbps prevents any preset from doing true justice to the supply materials, however as soon as once more medium will get the closest and gives an enchancment over quick.

The quicker preset appears horrible so once more I’d counsel quick as absolutely the naked minimal for any such content material, actually I’d advocate medium at a better bitrate however hey, Twitch has set the restrict to six Mbps so it’s mainly the very best we will do.


But picture high quality is just one a part of the equation, after all, the opposite is efficiency, and once you’re streaming your gameplay from the exact same pc you’re taking part in on, it’s essential that each your gameplay expertise and the efficiency of the stream are enough.

We’ll begin right here by taking a look at GPU encoding and see how that impacts efficiency…

Enabling both Pascal or Turing’s NVENC engine impacts the body price of the sport by round 10 to 20% relying on the sport, in different phrases, you’ll see a 10 to 20% drop to border price when capturing footage utilizing NVENC, in comparison with not capturing the sport in any respect. The extra GPU restricted the sport is, the extra of an affect NVENC can have, which is why Forza Horizon Four is impacted extra closely than the heavy CPU consumer in Assassin’s Creed Odyssey.

The excellent news, although, is whilst you’ll be operating the sport at a decrease framerate whereas NVENC is working, the stream itself can have excellent efficiency with no dropped frames, even when the sport is utilizing 100% of the GPU. AMD’s encoding engine doesn’t affect the sport’s framerate practically as a lot, however it drops about 90% of the frames when the GPU is being closely used, making it ineffective as we already mentioned earlier.

Software encoding efficiency is determined by the kind of sport you’re taking part in. In the case of Assassin’s Creed Odyssey which closely makes use of each the CPU and GPU, streaming utilizing the CPU can have a noticeable have an effect on on body price, and prime quality encoding presets will battle to maintain up.

With the Core i7-8700Okay and the RTX 2080 taking part in Odyssey utilizing our customized high quality preset, we have been solely in a position to encode the sport utilizing the x264 veryfast preset with out affected by body drops within the stream output. X264 veryfast encoding additionally diminished the body price by 17%, which was a bigger discount than merely utilizing NVENC. Veryfast encoding is healthier visually than NVENC for any such sport, so the efficiency hit is value it.

However transferring to even the ‘faster’ preset introduces body drops into the stream output. With a body drop price of 8.5%, the output is stuttery and onerous to observe. Meanwhile, sport efficiency has dropped from 90 FPS on common, to simply 63 FPS with a 1% low solely simply above 30 FPS. It’s clear this preset is choking the system. And it will get worse with quick and medium, which see body drop charges of 62 and 82 p.c respectively. Interestingly, sport efficiency is barely higher with these presets than with quicker, however I believe that’s as a result of encoder being overwhelmed which permits the sport to get a small quantity extra CPU headroom for rendering the sport.

One technique to enhance efficiency is likely to be to cap the sport to 60 FPS, as these watching your stream will probably be restricted to 60 FPS anyway. But with this cover in place, the story isn’t significantly better: the quick preset nonetheless sees 9% of all frames dropped, whereas the quicker preset simply scrapes in with no body drops, however with a 1% low within the sport of round 40 FPS. The solely possibility to make use of quick could be to cut back the visible high quality and take a look at once more, however for this text we weren’t actually occupied with optimizing Assassin’s Creed particularly for streaming with our {hardware}.

With the 8700Okay restricted to veryfast streaming or GPU streaming on this title, it is going to be attention-grabbing to see how different CPUs stack up partially 2 of this investigation. But definitely with the 8700Okay – a high-end, widespread gaming CPU – what we’ve proven here’s a typical state of affairs for streaming in a title that closely makes use of the CPU and GPU. Those with lower-tier CPUs and specifically, decrease core depend Intel CPUs, will run into this veryfast restrict extra typically.

As for Forza Horizon 4, which is way much less demanding on the CPU, it’s an attention-grabbing scenario as a result of software program encoding on the CPU truly delivers greater sport efficiency than {hardware} accelerated GPU encoding. This is as a result of there may be loads of CPU headroom to encode on the CPU with out consuming in to GPU efficiency.

Using the x264 veryfast preset impacted sport efficiency by 6% taking a look at 1% lows, however the distinction between veryfast and quick was solely an extra 5% drop regardless of the huge improve in CPU energy required to encode utilizing the quick preset.

On the stream aspect, we noticed no body drops with the veryfast and quicker presets, nevertheless transferring to quick noticed a 12% body drop price for the encoded stream. This brought about disagreeable stuttering within the stream. However contemplating we’re operating the sport at practically 120 FPS, we will fairly simply implement a 60 FPS cap to cut back the sport’s stress on the CPU. With that cap in place, the quick preset turns into usable with zero body drops within the output. The cap additionally opens up the choice of medium preset encoding, though with the 8700Okay we nonetheless noticed round a 2% of all frames dropped with the 60 FPS cap in place, which isn’t very best. If we wished to go along with medium encoding we’d have to take a look at lowering the sport’s CPU load by high quality setting tweaks.

Wrap Up (Until Part 2 of this Series)

So with all that testing carried out, there’s a couple of attention-grabbing takeaways right here. The key discovering for GPU patrons for the time being is that Turing’s GPU encoding engine for H.264 isn’t considerably improved in comparison with Pascal and positively doesn’t flip GPU encoding right into a viable possibility for streaming.

The solely time I’d counsel utilizing NVENC is with quick paced, excessive movement video games with a system that can’t CPU encode utilizing the x264 quicker preset or higher. Games with much less movement must be encoded utilizing the veryfast x264 preset fairly than NVENC, and veryfast must be achievable on most PCs which have been constructed with streaming in thoughts.

On the AMD entrance, their encoding engine wants loads of work to be even thought of. It doesn’t work with excessive GPU masses and when it does work, the output high quality is horrible.

CPU encoding is clearly a extra tough story as what degree of x264 encoding you possibly can handle will rely in your CPU and, crucially, the kind of sport you’re taking part in. With our 8700Okay system we ranged from being caught with veryfast encoding in a CPU demanding sport, to having the ability to use the quick and even medium preset with a gradual 60 FPS sport output at first rate high quality settings in a much less CPU demanding title.

But what streamers must be aiming for is to make use of the quick preset at a minimal, that’s the primary preset the place the output high quality is first rate sufficient at 6 Mbps for Twitch streaming, and whereas it’s not incredible for quick movement scenes, quick is significantly better than both the quicker or veryfast presets but it’s nonetheless achievable on first rate {hardware}. Medium can also be value making an attempt for these with top-end methods, whereas I actually wouldn’t hassle with any of the even slower presets.

While it’s good to have the ability to sport and stream on the one PC, this recommendation actually solely applies to informal or part-time streamers. Anyone who’s streaming professionally or full time ought to use a second, devoted stream seize PC with a good seize card and CPU. This then totally offloads the encoding work, permitting you to comfortably use the medium preset or slower for the very best quality streams, with out impacting your sport efficiency.

We’ve now found what the optimum presets are from a top quality perspective. The second a part of this sequence on sport streaming we’ll examine which CPUs are able to encoding at these presets, so keep tuned for that.

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