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4K is a bigger number than 1080p, but that doesn't mean it's better. This is especially true when it comes to 1080p Blu-ray video compared to 4K streaming. There's more to a video's quality than resolution, and Blu-rays have it.

The Elements of Picture Quality

Terms like "4K UHD" or "1080p"  refer to only one factor that makes up overall image quality. Specifically, it refers to the number of pixels or "picture elements" in each frame of video. A 4K UHD (Ultra High Definition) image has around eight million pixels, while a 1080p image has a "mere" two million or so individual pixels.

While this means that a 4K image technically has four times the fine detail of a 1080p image, this is not the only thing that matters to our perception of image quality. That's why the assumption that any 4K video will look better than any 1080p video is flawed.

Several other factors have a major impact on image quality:

  • Bitrate: The amount of data used to represent each video frame can significantly impact image quality. A higher bitrate can result in less compression and more detail in the video.
  • Color depth: The number of colors that a video can display can also affect image quality. A higher color depth allows for more subtle color variations and smoother gradients, resulting in a more natural and lifelike image.
  • Dynamic range: The dynamic range refers to the range of brightness levels that a video can display. A higher dynamic range can result in more detail in the shadows and highlights, making the image more realistic.
  • Compression: Compression is necessary to reduce the file size of videos, but too much compression can result in a loss of detail, pixelation, and other visual artifacts.

In general, Blu-rays have an advantage over 4K streaming videos regarding bitrate and color depth, which we'll unpack below. They're also much less compressed, so you won't see compression artifacts. Especially since the disc is mastered and quality assured before being mass-produced.

One area where 4K streaming has a distinct advantage over standard Blu-ray movies is when it comes to dynamic range. Only 4K UHD Blu-rays support HDR, but it's becoming common with 4K streaming. A good HDR 4K stream will knock the boots of a standard 1080p Blu-ray without HDR. At least when it comes to this particular feature.

Blu-ray's Bitrate and Color Depth Advantage

A 1080p Blu-ray disc typically has a much higher bitrate than a 4K compressed video stream. This means the Blu-ray can use more data to represent each frame, resulting in a clearer and more detailed image than the highly compressed 4K video stream. The extra data allows for a wider range of colors, more detail in the shadows and highlights, and less visible compression artifacts such as pixelation and blurring. You'll often hear of "crushed" blacks in compressed video, which refers to the loss of details in dark areas.

Related: Which Streaming Service Has the Best Video Quality?

Another advantage of Blu-ray discs is that they are not subject to fluctuations in internet speed. This means that you can consistently enjoy high-quality video without buffering or quality drops that can happen when streaming video online. With a Blu-ray, you can be confident that you'll get the best possible image quality without worrying about internet speed.

A typical 4K stream might consume around 25Mbps while a standard Blu-ray uses around 40Mbps, but don't forget that the 4K stream has four times the pixels, so the bitrate advantage on a per-pixel basis is significantly more than these two numbers suggest by themselves.

Can You See 4K's Crispness?

The ability to see the difference between 4K and 1080p video depends on a few factors, including the size of your screen, how far away you are from the screen, and the quality of the video itself.

If you're sitting too far away from your TV, you may not see the difference between 4K and 1080p video. That's because the further away you are, the harder it is to see individual pixels.

Video quality can also impact your ability to see the difference between 4K and 1080p. If a 4K video has been compressed heavily or is low quality, it may not look better than a high-quality 1080p video regardless of where you're sitting.

Another wrinkle to this story is that modern 4K TVs have become very good at upscaling 1080p video to 4K. In the case of 1080p Blu-ray content, the high bitrate gives the upscaler a lot to work with, so in the end, the upscaled Blu-ray may be very 4K-like in resolve while maintaining the color depth and motion detail advantages of Blu-ray.

Related: Are You Watching 4K Content? Here's How to Tell

Blu-ray Audio is in Another League

Thanks to higher bitrates and less compression, Blu-ray audio generally offers better sound quality than typical streaming audio.

Blu-ray discs can use lossless audio formats, such as Dolby TrueHD and DTS-HD Master Audio, which can deliver sound quality identical to the original studio master. These formats use higher bitrates and less compression than typical streaming audio, resulting in more detail, clarity, and depth in the sound.

In contrast, typical streaming audio often uses lossy compression, meaning some audio data is discarded to reduce file size. While this compression can help streaming audio to be delivered more quickly and smoothly, it can also result in a loss of detail and a more compressed, less dynamic sound.

That said, it can depend on your specific audio equipment. You may not notice much difference if you don't have sound equipment to take advantage of that extra clarity. If your audio goes through a Bluetooth system, even Blu-ray audio becomes compressed with a lossy audio algorithm.

Streaming Artifacts Can Spoil Your Fun

Common visual artifacts that can occur with 4K streams on services like Netflix or Hulu include compression artifacts, banding, and macro blocking.

Compression artifacts are caused by the heavy compression used to deliver 4K content over the internet. They can manifest as pixelation, blurring, or smearing of fine details and can be especially noticeable in fast-moving scenes or areas of high contrast, such as text on a background.

Related: What Is the Dirty Screen Effect?

Banding occurs when the image has visible gradients of color rather than a smooth transition. This can be especially noticeable in areas with subtle color gradations, such as skies or shadows. Banding is caused by the limited bit depth of the video, which can result in color information being lost during compression. Even on a 1Gbps connection, your author witnessed severe banding in Amazon's The Rings Of Power streaming at 4K, along with prominent color and motion issues.

Macroblocking is a compression artifact that appears as large blocks of pixels in the image. These blocks can be distracting and reduce the video's detail and clarity. It looks like an image break-up and wouldn't be allowed on a professionally-mastered, quality-controlled Blu-ray.

All of these visual artifacts can affect the viewing experience by reducing the detail and clarity of the image. They can be especially noticeable on larger screens or with higher-end equipment, but the difference is obvious on even entry-level modern displays.

Grab Those Blu-rays While You Can

There's a good chance that Blu-ray will be the last mainstream optical format. Going ahead, your only option may be to buy or rent digital movies and series. Of course, just like you can buy lossless digital music today, you'll likely get to buy massive digital video files that equal Blu-rays in quality. Then again, it will be some time before routinely downloading 50GB of data for a single movie becomes commonplace.

However, compression technology is improving, so video quality comparable to Blu-ray may meet the further spread of high-speed internet halfway. We don't know how long it will take, but there will come a time when streaming, and downloadable movies will objectively offer better quality than Blu-ray, but that still leaves other weaknesses of digital purchases, such as having no guarantee that your access to that content will be perpetual.