Upscaling on TVs
Resolution, Sharpness

Updated

Upscaling is a feature that increases a lower-resolution video’s pixel count to make it match the pixel count of a higher-resolution TV's screen. This is what allows lower-resolution video to fill a higher-resolution screen and not just take up a small portion of it. If you have ever watched a DVD displayed on an HD TV, you’ve experienced an example of upscaling. Because upscaling is used virtually any time a video with a lower resolution is played on a higher-resolution screen, the quality of a TV’s upscaling is fairly important.

To test for upscaling, we display a 480p, 720p, 1080p, and 4k image on all the TVs we test and subjectively evaluate how good they all look. For 8k TVs, we also display an 8k image to see if it's displayed properly.

Test results

When It Matters

Good 720p reproduction- as crisp as it gets
Poor 720p reproduction- too blurry

A TV's upscaling is a determining factor in how good an image of a given resolution looks on screen, and applies to all video. Good upscaling will do a good job of translating detail from lower resolutions to the higher-resolution pixel count of the screen, keeping images crisp. Poor upscaling will do a bad job of translating this detail, rendering the image blurry or overly sharp. Above, compare good upscaling (left) with poor upscaling (right).

It’s worth noting that most people aren’t very bothered if a TV has poorer upscaling, and that is because quality mostly relies on the level of detail contained within the media itself; for example, no TV can make 480p video look great because it’s a low resolution with little detail. While it is best to get a TV that does a good job of upscaling, it’s not the end of the world if you get a model that isn’t quite as good – the difference won’t be that stark. It’s also worth noting that if a device other than the TV is doing upscaling – like a receiver, an upscaling Blu-ray player, etc. – these test results won’t matter at all.

Not everyone needs to be concerned with upscaling quality for all resolutions. To determine which resolutions matter to you, consult this list of some common examples of media and their associated resolutions.

480p | 640 x 480 pixels OR 720 x 480 pixels

  • DVDs
  • Standard-definition TV
  • Old game consoles

720p | 1280 x 720 pixels

  • High-definition TV
  • High-quality streaming
  • Xbox 360 & PS3

1080p | 1920 x 1080 pixels

  • Blu-ray
  • HD Streaming
  • PS4
  • Xbox One
  • Nintendo Switch

4k UHD | 3840 x 2160 pixels

  • UHD Blu-ray
  • 4k/UHD Streaming
  • PC
  • PS4 Pro/PS5
  • Xbox One X
  • Xbox Series S|X

8k | 7680 x 4320 pixels

  • Streaming services
  • PC games

Our tests

All our upscaling evaluations are based on the subjective impression we get from pictures of different resolutions displayed on a TV. All TVs are tested under our calibrated settings, and we consider crisp, detailed reproduction of the pictures to be ideal.

Lower scores are assigned if

  • A TV upscales a resolution blurrily
  • A TV adds too much sharpness when upscaling a resolution

We perform this evaluation for a few different resolutions, and it’s important to note that each resolution is always held to its own standard. Even the best TVs can’t make lower resolutions look as good as higher ones.

480p

Our test video

Our 480p test evaluates how well a TV can upscale an image with 640 x 480 pixels or 720 x 480 pixels to fit the screen's resolution. 480p video is standard definition and is used by media like DVDs or standard-definition TV channels. This test will matter to you if you watch that kind of video, but isn’t important if you stick with HD media.

For 480p content, we display a video of a static image. Since 720p content typically has a low bitrate, displaying a video allows us to introduce the temporal artifacts found with low bandwidth video; this lets us more accurately simulate how the TV will look with 480p content.

Good 480p upscaling - as crisp as it gets
Poor 480p upscaling - too soft

It’s important to note that because the quality of 480p is so low, even top performers on this test won't produce an amazing picture. Above, compare a TV that is pretty good for 480p upscaling (left) with one that produces a softer image and isn’t as good (right). You can see some detail is lost in the softer picture, but also that neither looks great.

720p

Our test video

Our 720p test evaluates how well a TV can upscale an image with 1280 x 720 pixels to fit the screen's resolution. 720p is sometimes called ‘HD-ready’ and is used by some HD cable channels, older video game consoles like the Xbox 360 & PS3, and some video streaming services. This test is pretty important for those kinds of media, but it won’t matter if you don’t watch them.

For 720p content, we display a video of a static image. Since 720p content typically has a low bitrate, displaying a video allows us to introduce the temporal artifacts found with low bandwidth video; this lets us more accurately simulate how the TV will look with 720p content.

Good 720p upscaling - as crisp as it gets
Poor 720p upscaling - too blurry

Above, compare a TV that is pretty good for 720p (left) with one that is softer (right). You can see that with the poorer model, there’s a significant loss of detail in the bushes and on the water and that the whole image looks smoother than ideal.

1080p

Our test photo

Our 1080p test evaluates how well a TV can upscale an image with 1920 x 1080 pixels to fit the screen's resolution. 1080p is sometimes called ‘Full HD’ and is used by Blu-rays, PC games, last-gen video games (mostly Xbox One & PS4), and most streaming video. If you watch those kinds of media, the results of this test are going to be quite important to you.

For 1080p TVs, 1080p is the native resolution, meaning a 1080p signal fits perfectly, with no upscaling required to make the image fit. These TVs receive a perfect score for this test. However, the results of this test do matter when evaluating 4k models, as they do need to upscale 1080p.

To test for performance with 1080p, we display our 1080p test photo on the TV and evaluate how well it is reproduced. If the picture is too soft, or if there's over-sharpening of the image, the TV will get a lower score. Unlike the 480p and 720p tests, here we use a static image, as most 1080p content is at a high enough bandwidth that temporal artifacts shouldn't be an issue.

4k

Our test photo

Our 4k test evaluates how well a TV can display an image with 3840 x 2160 pixels. 4k is also known as ‘UHD’ or ‘Ultra HD’ and is used by UHD Blu-rays and some streaming video. If you watch those kinds of media or would like to in the future, you should make sure you get a TV that does well on this test. If you’re unsure, take a look at our thoughts on the difference between 4k and 1080p here.

Most TVs supporting a UHD input have UHD as a native resolution and don't upscale 4k video. Most of them will get a perfect score on this test. However, some TVs use an inferior ‘type’ of UHD resolution; instead of using 3840 x 2160 regular pixels (each with a red, green, and blue subpixel), these TVs throw in white subpixels to bring a lower resolution up to UHD. Because these white subpixels can’t produce color, their inclusion means UHD on these TVs will look less detailed than on those with normal pixel structure.

To test a TV’s performance with 4k resolution, we display our 4k test image on the screen and see how well it reproduces. If we see the picture is too soft, the score will be lower. 1080p TVs score a '0' on this test, as they can't display 4k at all. For some examples of the types of issues that can be seen on some 4k TVs, take a look here. Unlike the 480p and 720p tests, here we use a static image, as most 4k content is at a high enough bandwidth that temporal artifacts shouldn't be an issue.

8k

Our test photo

Our 8k test evaluates how well a TV can display an image with 7680 x 4320 pixels. 8k content is still extremely rare, with only a few streaming services offering a handful of videos. If you watch those kinds of media or would like to in the future, you should make sure you get a TV that does well on this test. If you’re unsure, take a look at our thoughts on the difference between 8k and 4k here.

All TVs supporting an 8k input have 8k as a native resolution, and so don't upscale 8k video. Despite that, most of them don't currently get a perfect score. 8k is still a very new format, and the processing and panel technology is still in its infancy. Most 8k TVs we've tested can't display a perfect 8k signal. Many of the ones we've tested show signs of dithering, which can be seen in the shadows of some content, but generally speaking, it's not too noticeable.

To test a TV’s performance with 8k resolution, we display our 8k test image on the screen and see how well it reproduces. If we see the picture is too soft, the score will be lower. 1080p and 4k TVs score a ‘0’ on this test, as they can't display 8k at all. Unlike the 480p and 720p tests, here we use a static image, as most 8k content is at a high enough bandwidth that temporal artifacts shouldn't be an issue.

Additional Information

How upscaling works

Upscaling is the process used to make videos with smaller signal resolutions fit a screen with a larger resolution. It doesn't improve the look of the video, as it can't add detail that isn't included in the source signal.

The most basic kind of upscaling increases signal resolution by taking a smaller video resolution and inserting transitional pixel values in between the ones included in the signal. For example, ‘Pixel 1’ and ‘Pixel 2’ sandwich the newly created ‘Pixel 1.5,’ a hybrid of their values. This allows the TV to retain the same basic picture but enlarged. Unfortunately, solely applying this process makes the picture look a bit blurry.

Most TVs use more advanced techniques for upscaling than this, often applying extra sharpness, or changing color values slightly to make the image closer to the intended crispness. Though we can’t say exactly what each TV is doing when it upscales a lower resolution, when we evaluate TVs for their upscaling, we’re evaluating the quality of the upscaling algorithms they use.

Sharpness

On TVs, the ‘Sharpness’ setting changes the number of high frequencies in the video. High frequencies manifest as sudden changes in the picture; for example, the edge of an object against a background. Increasing a TV’s sharpness setting increases the number of high frequencies in the video, and visually, this means the distinction between objects is exaggerated by increased contrast along edges. You can see below that this means the darkness of the line around objects is deepened, and the space beside those lines is lightened.

No added sharpness
4k UHD resolution
Overharpened
4k UHD resolution

Increasing sharpness may appear to add definition, but it normally reduces detail, as the details that were originally along edges are overwritten. It can also make noise in the signal worse. Because of this, added sharpness is usually undesirable. However, when a TV is upscaling low resolutions like 480p and 720p too softly, increasing sharpness can help to clarify the blurry picture; the tradeoff of losing a little bit of detail might be worth it. For that reason, it’s common for upscaling to automatically introduce extra sharpening to low resolutions, and it’s also common for people to increase sharpness manually.

If we see a TV automatically adds sharpness when upscaling a resolution, we note whether it is strong to the point that it negatively affects the picture. If we see a resolution looks blurry, we note whether adding a bit of sharpness helps to clarify the image.

Noise removal

Noise removal features remove compression artifacts from the time and space domains of video. These artifacts are most noticeable when they manifest as staticky or pixelated spots on the video. Low-quality video (like 480p and 720p) is more likely to include these artifacts in the signal, as those media are typically older, and use worse compression algorithms that result in more visual artifacts.

Most TVs include noise removal settings that can help remove an amount of extra noise from the video. To remove the noise, the TV will essentially try to undo the effect of the video’s compression by applying a filter to the signal and blocking certain frequencies from being displayed in the image. This can reduce the sharpness of the video, so while this can help to remove some of the noise, it also often leads to video looking blurrier than it did before.

How To Get The Best Results

For best picture quality, you should watch higher-quality media. For those who are interested in 4k, we list our favorite 4k TVs here.

Beyond that, if you need to be able to watch lower-quality video, be sure to get a TV that does a good job upscaling all the resolutions you intend to watch.

When watching 480p or 720p, if you find the picture looks too soft, try making a very small increase to sharpness. Do this until you get a little more definition, but stop before adding harsh lines or big halos to objects.

With low-quality media that exhibits lots of noise, it can also be a good idea to enable noise removal features. Try these features out and leave them enabled if you like the effect, and disable them if you find the picture becomes too blurry.

Related Settings

  • MPEG noise reduction: Helps remove noise contained within low-quality media (standard-definition TV, DVDs, etc.). Shouldn’t be used with HD video.
  • Noise reduction: Blocks out compression artifacts and noise found in digital media. Can improve the look of streaming media and HD channels, but shouldn’t be used with Blu-rays.
  • Sharpness: Makes edges of objects stand out. Increasing it can improve detail in blurry low-resolution video.

Other Notes

  • When looking at source info on a TV, the signal's resolution is listed, not the screen's resolution
  • One way to get less noise in the picture is to watch higher quality video. Here are common video sources in descending order of quality:
  1. UHD Blu-ray
  2. Blu-ray
  3. High-quality streaming
  4. Over-the-air (w/ good reception)
  5. HD cable/satellite
  6. DVDs
  7. Standard definition cable/satellite
  8. Low-quality streaming

Conclusion

Upscaling is a feature TVs use to make lower resolutions fit their screen. Good upscaling preserves detail in an image, making the picture look properly crisp, not blurry or overly sharp. For that reason, you should make sure you get a model that performs well with all the resolutions you watch. We verify all the TVs we test for their capability with 480p, 720p, 1080p, and 4k resolutions (when supported).

If you find a given resolution upscales blurrily on your TV, you can increase the sharpness a little to add the definition you’re looking for. If you notice there's lots of random noise in the picture, you can enable noise reduction features to help get rid of that. With good resolution support (or the right adjustments), you’ll be able to enjoy lower resolutions that look as crisp as they can.

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