video encoding showdown

How to use the latest GPUs to boost your livestreaming video quality

by Jarred Walton

© OLLY CURTIS/ACTIVISION

THE ERA OF PHYSICAL MEDIA is largely dead and buried. Though many people still have old VCR tapes, stacks of DVDs, and the more modern Blu-ray discs at home, mention optical discs and the rising generation won’t know what you’re talking about.

We’ve long since stopped including recommendations for optical drives in our PC builds, though it’s still possible to buy a Blu-ray drive for a PC—just like it’s possible to ignore the smart features and connectivity options most TVs now include, and instead opt for a 30-second delay while the Blu-ray player loads up a menu screen. Our quest for instant gratification via Netflix, YouTube, Twitch, or any number of other streaming services means that people are more comfortable using Roku than a DVD.

The consumption of streaming videos dwarfs the production of content, but it’s in the creation stage that quality levels are defined. H.264 remains the most popular video codec of the past decade but as we cram higher resolution and higher quality content into the same bandwidth, its reign may be coming to an end. The good news is that its replacement could already be here.

The Sony Large screen 65in rear projection TV was released at $3,000 in 2004.

THE NEED FOR COMPRESSION

THE PRIMARY REASON for any video codec—coder/decoder—is to enable the transmission of content without requiring lots of bandwidth. Take a standard movie with a 1080p resolution, running at 24fps: 1920 × 1080 × 24 (fps) × 3 (bytes per pixel) × 8 (bits per byte) = 1,194,393,600 bits of data for every second of uncompressed video. People with faster than gigabit connections might be able to handle that sort of data stream, but it’s inefficient.

But 1.2Gbps of data is only for 24fps content. A graphics card running at 1080p and 60Hz sends 3Gbps of data to the display. Modern high refresh rate displays can transmit at up to 54Gbps in the case of AMD’s DisplayPort 2.1 connection—4K at 240Hz for instance needs about 48Gbps. But sending gigabits of data over an HDMI or DisplayPort connection is one thing; sending it over the internet or storing content on a hard drive or SSD is another.

Using a video codec is like using JPG or PNG compression for images, rather than uncompressed bitmaps, but with video, there’s a third dimension available. Where a high-quality JPG file might be able to reach compression ratios of 12:1, video codecs can take uncompressed video and deliver good-quality alternatives with compression ratios of 250:1, 500:1, and even 1000:1 or more. And it’s a good thing because it’s what makes video streaming practical.

When you watch a 4K 60fps YouTube video, your PC sends around 12Gbps of data to your monitor. Your internet connection probably only has to deal with about 20Mbps. But not all video codecs are created equal, with differences in the algorithm, hardware requirements, and licensing costs. We’ve covered the three major contenders below.