Stream 864p or 936p for 1440p Gaming?

Gaming on 1440p monitors has become more popular with time now, and many gamers are starting to transition over from their 1080p monitors. However, have you noticed downscaling 1440p gameplay to 1080p on stream the graphics and texts do not look as crisp and almost blurry? Here we will discuss the reasonings and methods behind choosing the best downscaling output resolution to provide the best quality stream for your viewers.

The information provided is from our own research and trial and error so that you do not need to guess or work it out the hard way; although what works best for us may require some tweaking on your end to work best on your particular computer setup. Perhaps you want a different resolution that works better or a higher bitrate; ultimately, it’s for you to decide. This guide provides some documented information regarding 1440p gaming for streaming as most people still use 1080p monitors for gaming.

Here are some terms to familiarize yourself with as you continue reading:

  • Bandwidth/Bitrate: you should aim your bitrate to be as minimal as possible to allow the widest range of viewers to have accessibility watching. Note that less bitrate equates to less data transferred resulting in a lesser quality image.
  • Encoding: image quality is lost due to compression, but reducing bitrate required.
  • Downscaling: image quality is lost as you are transferring fewer pixels than the original video, but reducing bitrate required.

Why Streaming 1080p isn’t best option for Twitch

Streaming in 1080p on Twitch may not be the best option for most streamers. Unless you are a Twitch Partner, the available bitrate is capped around 6,000 kbps with no guarantee for transcoding options for viewers with slower internet speeds. Because of this, 1080p may become over compressed depending on the game streamed resulting in a low quality image since the bitrate is not high enough to support.

It simply comes down to higher resolution means more pixels with results in more data to be transferred. So either high bitrates are needed to support more data movements or you must compress the video more. The more you compress the worse the picture quality becomes. To combat compression you can reduce resolution, reducing data, but also reducing picture quality due to fewer pixels. Each method has diminishing returns and one must balance performance and quality.

This is why 1080p is generally not recommended for non-partnered Twitch streamers as fitting 1080p data into 6,000 kbps causes a lot of compressions resulting in bad picture quality especially seen in FPS games of high movement. You have probably seen 720p recommended in many places, but what about 864p or 936p?

Why 864p or 936p?

The goal is to find the best tradeoff between crisp resolution for your audience while also allowing a manageable bitrate for those with slower internet speeds. While maintaining a true 16:9 aspect ratio for video resolution as literally everyone except a small minority use this ratio, we can review the compatible aspect ratios available. The goal is to choose resolutions at least divisible by 8 because the h.264 encoding algorithm divides the video frames into 8×8 macro-sections to handle the compression formatting.

It should be noted that the h.264 encoding algorithm also uses 16×16 macro-sections during its compression. This means finding a resolution divisible by 16 would produce the best downscaled image, but that further limits available resolutions to choose and why most settle for divisible by 8. It is important to use one of those because of the way h.264 encoding works. The encoder breaks down your picture image into square sections to figure out how to compress them, and if we don’t use one of those resolutions divisible by at least 8 then the downscale ratio with not be even and it will try splitting individual pixels partially – which it cannot do so image quality becomes defective and thus quality suffers. By not using a resolution divisible by 8 or 16 will require the encoder to have to fill voids in the image by using padded (junk) pixels.

Luckily, we can reference this resolution table by Pacoup highlighting the best resolutions divisible by 8. Seen on the table available options are 1408×792, 1436×864, 1664×936, and 1792×1008 for the options below 1080p resolution.

Testing out these four downscaling options. Downscaling 1440p to 792p becomes too pixelated and is not too unpleasant on the eyes. When trying to downscale to 1008p from 1440p, the compression becomes too much and again the video image suffers in quality. So this leaves the middle options 864p and 936p as the best viable options to investigate further. Below we dig deeper.

Downscale to 936p

Downscaling 1440p gameplay to 936p resolution requires less downscaling compared to 864p but results in an uneven downscaling ratio of 65/100 causing the image to compress more and to look more pixelated during fast-moving environments during gaming. Here’s some math explaining this reasoning:

First, some assumption variables are defined. Aspect Ratio: 16:9, Frame Rate: 60 FPS, Pixels are 24 bits (8 red, 8 blue, and 8 green), and Bitrate: 6,000 kbps.

Calculating the compression would look like this:
(((16/9)*936)*936*60*24 / 6,000,000 = 373.8 <– this is not a bad ratio

However, the downscale ratio is not even:
936/1440 = 0.65 or in other words (65/100) ratio.
This is less than ideal because we now have partial pixels which are not a thing. The image quality will be a bit skewed and blurry as the encoder tries to compensate for how to handle splitting pixels into smaller pieces than it can handle. This causes artifacts to show up in the image due to every 5×5 1440p pixel section becoming a 3×3 936p pixel section with 0.25×0.25 pixel lost due to being fractional.

Downscale to 864p

Downscaling 1440p gameplay to 864p resolution is the best streaming option for non-partnered Twitch streamers. The downscale looks better, where ever 1440p 5×5 pixel section becomes an 864p 3×3 pixel section. This provides less compression so any moving picture has less pixelation and looks the best out of other downscaling resolutions.

Now let’s calculate what the compression ratio would look like for 864p under the same assumptions:
(((16/9)*864)*864*60*24 / 6,000,000 = 318.5 <– not a bad ratio either.

And reviewing the downscale ratio:
864/1440 = 0.60 or a (60/100 –> 6/10) ratio. This is a nice and even ratio with no partial pixels occurring. A nice complete downscaled image will be presented. This goes back to the comment that every 5×5 1440p pixel block will become an even 3×3 864p pixel block.

Honorable Mention 720p

Streaming downscaled to 720p may be the best option to stick with if you are finding 864p not working out for the particular game you are playing. The reason being is 1280×720 is perfectly divisible by 16 making it the best downscaling option for encoding efficiency. Sure, there’s clearly quality loss due to changing resolution from1440p to 720p, but with the appropriate bitrate should present a very clear stream for your viewers.

Conclusion

Mathematically, 864p proves to be the best option for downscaling and encoding efficiency when gaming at 1440p. Whether it’s practical for your particular streaming setup is something you should experiment with in test streams. If you aren’t satisfied with the image quality try bumping up the bitrate if your internet speed can handle it or jump up to 936p downscaled resolution to see if the results are better.

Nevertheless, if either option is not ideal for quality, simply go back to downscaling to 720p with 6,000 kbps bitrate and enjoy probably the best downscale solution for 1440p gaming. There are plenty of Twitch Affiliate streamers who keep to 720p and still see consistent channel growth. And to be honest, most viewers won’t even notice a quality difference when viewing 720p to 864p. At the end of the day, focus on providing a consistent image quality with entertaining content, and viewers will come. Once you hit Twitch Partner you can consider jumping up to 936p or 1080p with a higher bitrate cap allowed.

Lastly, remember it’s simply just a balancing game for downscaling. Too much downscaling looks bad because you are essentially losing picture detail in reduces pixels. Too little downscaling provides more pixels, which is more data to be compressed, and more compression results in poor image quality especially in high movement gameplay. Increasing bitrate will improve image quality and provide more room to play with in compression, but viewers may not have the internet speed available to load your streams and will have the video consistently buffer to catch up – resulting in leaving to watch somebody else. Most importantly, it is crucial to only downscale to resolutions that are at least divisible by 8 and, if possible, by 16.