AV1 Codec: Your Primer for the Future of Online Video

AV1 is a video codec that is promising to be the future of online video streaming. But what is AV1 and what exactly does it claim to do? We’ll answer those questions and many more in this primer.

What is a Codec?

Let’s start with the basics. A codec is a compression algorithm that allows you to watch online videos instantaneously. “Codec” comes from smashing together the words encoder and decoder, and depending on the media you’re watching you may only be experiencing one or the other.

An encoder is a technology that compressed a video file so that it has a smaller file size. A decoder then uncompresses that video so that it will play on your device. Unfortunately, the compression process will degrade the quality of the video as compared to the original. But because of these small file sizes, we are able to enjoy instant video access on all of our devices. And with so many videos being uploaded every day, it’s important for companies to save space on their servers where they can!

It is generally very important for live content to be heavily encoded, especially when users are streaming with 4K or other high-quality equipment. This is often done on the user’s end through the software or hardware that they are livestreaming from. This makes it easier for the video data to go from the user to the streaming service regardless of connection speed.

In addition to encoding and decoding, another important term to know is transcoding. This is the technology that allows you to change the video quality on websites like YouTube.  That button doesn’t adjust the quality live – there are actually different versions of the video at different quality levels, which were transcoded from the original high-quality video.

Previously, H.264/AVC and H.2265/HEVC have been the most popular codecs, but the AV1 codec is attempting to challenge their superiority.

Why is AV1 Better?

AVC and HEVC are popular and efficient, but AV1 has some distinct advantages.

While many consumers won’t care one way or the other, some will be happy to know that AV1 is a royalty-free and open-source technology. It was created by the Alliance for Open Media, which is headed by major tech companies. The alliance is governed by Amazon, Apple, ARM, Cisco, Facebook, Google, Huawei, Intel, Microsoft, Mozilla, Netflix, Nvidia, Samsung, and Tencent. These companies are incentivized to develop and adopt AV1 because of the licensing fees of AVC and of HEVC.

The Alliance for Open Media is actually a continuation of Google’s WebM project. WebM is a royalty-free alternative to HTLM5 video and HTML5 audio. WebP is a similar format except for images. You’ve probably seen these file formats if you’ve downloaded a video or image in the last few years.

But being open-source is not enough, as is clear by previous failed attempts to create a new standard codec.

AV1 is more efficient than its predecessors. However, the details of how it works will only make sense to those who are technically inclined, so we’ll keep it simple here.

How Does AV1 Work?

Av1 claims to offer 30% better compression than H.265. This means that the compressed video takes up 30% less space while maintaining the same visual quality.

How Compressions Works

Let’s take a step back and explain compression (or encoding), as that is the underlying technology. At its core, lossless compression identifies distinct instances of the same pieces of data, only keeps one instance, and then creates a log of where all of the other instances were in the file. Then when the file is decoded, that log will be used to place the data in the correct location as if nothing happened. For example, if a specific pixel in a video is the same color for 100 frames, there will be a record more like “100 green pixels” than counting “green pixel” 100 individual times.

Lossy encoding will save more space but lose more information. Generally, files that were compressed using a lossy method will round off nonessential data that most users won’t perceive. H.264 and H.265 are both lossy compression formats, which allow users with all internet connection speeds to consume online content quickly.

How AV1 Works

The AV1 encoder starts by looking at a frame of video, and separating it into blocks of pixels called superblocks. These can be 128×128 or 64×64 pixels, but are able to be divided down to 4×4 if needed. The encoder can then create t-shaped partitions from these superblocks. Through all of these blocks, AV1 can differentiate distinct objects and create a more accurate separation between them. This is as opposed to other encoders, which can add a distinctive “stair step” pattern of pixels along the edges of objects.

What Stands in the Way of AV1

AV1 sounds great in every way compared to the previous standard, so why aren’t we using it everywhere? Unfortunately, AV1 does have some downsides, and it presents a chicken-and-the-egg problem. One of the biggest obstacles is the hardware, as not every device has a chip that can support AV1. Netflix has tried it out on certain Android devices and TVs, and Apple has not yet implemented it in its devices. Not having support in Apple products is a major setback for AV1. Qualcomm has also been hinting that they may skip AV1 in their mobile chips. Instead, they have their eyes set on another future codec, VCC (also called H.266). This codec is not free and not open-source, but it does promise to be 50% more efficient than HEVC.

YouTube uses AV1 encoding, but only on 8K videos, and of course only on devices that support it. Google has promised that all Android TVs produced after 2021 would support AV1. The Nvidia RTX 3000-series of GPUs supports AV1 decoding, but only newer graphics cards support AV1 encoding as well – that being Intel Arc, AMD RX 7000-series, and Nvidia RTX 4000-series. This is great for users who live stream, as those with newer hardware can take advantage of AV1’s benefits for their content.

Despite the lack of AV1 hardware support in devices still, the tide is turning and more and more devices are coming to support it.

How Does AV1 Affect Me?

For the most part, AV1 won’t affect people in an obvious way. Much like the codecs before it, most users are oblivious to the technical back-end of Netflix and YouTube. And (rightfully so) they don’t really care about how it works, as long as it delivers the content they want to access. How it will affect the average end user is that 8K content will become more available, livestreaming will be easier for those with the right hardware, and the quality of streamed media will most likely be higher. AV1 and other advanced codecs should slowly start slipping their way into our media consumption and silently improving our viewing experiences!