An Easy Explanation of the AOMedia Video Codec 1.0: AV1

By Allie Mellen on April 24, 2018
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By 2021, 82% of worldwide internet traffic will be video. In order to address this, the Alliance of Global Media Innovators released the AOMedia Video Codec 1.0 (AV1) on March 28, 2018 to improve drastically on older technology. According to independent member tests, AV1 boasts 4K UHD video at an average of 30% greater compression over competing codecs.

What is AV1, and How Does It Work?

AV1 is an open-source, royalty free video codec. The fact that it is a royalty-free video codec is important, because in addition to fostering large scale adoption, it allows small companies and startups to experiment without being encumbered by paying obscenely high royalties. It is designed with a low computational footprint, aims to bring consistent high-quality video, and is created for use in commercial and non-commercial content. It is supposed to deliver 30% better compression compared to alternatives, and is optimized for internet and related applications. While sources have found that AV1 surpassed its goal of 30% better compression than VP9, it requires longer encoding times compared to current options due to increased complexity.

The goal behind its creation was to make the next generation of video codec, succeeding current popular codecs including VP9 and H.265 by offering better performance. AV1 is built on three premises: being royalty free, open source, and ubiquitous. It competes with the IETF’s work on a royalty-free and open source codec, NETVC, whose efficiency goal is to improve compression by 25% over HEVC.

Royalty Free

AV1 is royalty-free. In order to achieve this, the development process for AV1 is designed in such a way that every adopted feature must be independently confirmed so that it does not infringe on competing company patents. HEVC, a main competitor of AV1 with contributions from 50+ companies, is not a royalty-free codec, and the contributing companies are parts of several different patent pools. This includes MPEG LA, HEVC Advance, and some by themselves. As all companies are not part of the same licensing pool, licensing from multiple authorities is difficult and a hindrance for small companies, and perhaps a hindrance to ubiquitous adoption of H.265/HEVC.

While unknown patent holders are a concern for AV1, this process is designed to minimize that possibility as much as is feasible. Additionally, unknown patent holders are also a problem for codecs that are royalty bearing. Therefore, it is still a better proposition to build on a confirmed royalty-free codec with known patent holders, as the unknown exist regardless.

Open Source

AV1 is an open-source codec, therefore all development occurs in public and is open for contributions. This was a large milestone for AOMedia that addresses great marketplace demand for an open standard.

Ubiquitous

AV1 scales to any modern device at any bandwidth. It is an integral part of AV1’s design that intends to specifically address the browser fragmentation problem. By resolving this issue, it looks to attain universal video interoperability across all browser and communication devices.

What is AOMedia?

The Alliance of Global Media Innovators (AOMedia) is an independent nonprofit made up of 12 founding members and 22 promoter members, including Amazon, Facebook, Google, Apple, IBM, and many others. Their main focus is to deliver open, royalty-free, and interoperable solutions for the next generation of video delivery. This includes making video technology more efficient, cost-effective, and higher quality for all users, on all devices, on all platforms using AV1.

How was AV1 Received?

Thus far, AV1 has been received very well.

Facebook, a member of AOMedia, tested AV1 and found that it surpassed its goal of 30% better compression than VP9. In fact, it accomplished significant gains of 50.3%, 46.2%, and 34% with regards to the x264 main profile, x264 high profile, and libvpx-vp9, respectively. However, it resulted in an encoding computational complexity increase by factors of 5721.5x, 5869.9x, and 658.5x with regards to the x264 main profile, x264 high profile, and libvpx-vp9 for CRF/QP mode, respectively. Facebook is planning to continue to promote its adoption into their production systems.

Bitmovin, a company that builds video infrastructure solutions for developers and is a member of AOMedia, completed a scientific evaluation of AV1 compared to VP9 and HEVC. They showed that AV1 outperformed VP9 and HEVC by up to 40% in scenarios involving Adaptive HTTP Streaming services with a specific setup.

Typically, the time it takes for widespread adoption in hardware and software is 3-5 years. Based on the news we have heard, we can speculate that Facebook Videos, YouTube, and Netflix will implement and rollout AV1 fairly quickly. In contrast, the hardware will take a few years. With each generation of the VPx, the hardware implementations have rolled out faster. For example, VP9 hardware encode was released within 3 years and devices since 2016 have carried support for it. Similarly, Apple implemented HEVC in iOS 11 in 2016/2017, which was within 4 years of standardization. All things considered, the timeline is reasonable, and with several large companies backing it, including all major browsers and several large streaming services, we think it will end up dominating the market by 2020.

What Does AV1 Mean for WebRTC?

AV1 was created to address the WebRTC codec war. On one side, we had the royalty-bearing and highly prevalent H.264, and on the other the royalty-free and implemented in a majority of the browsers, VP8. We ended up with both as Mandatory to Implement, and this created browser fragmentation. Safari does not as of yet implement VP8, and all other browsers implement both.

The current version of AV1 does not support a low-latency mode. Our sources with AV1 say that work is ongoing, and that the initial emphasis was to get the bitstream and coding tools standardized for the bigger use-case, video streaming. Real-time encoding should be announced shortly, and we at callstats.io are waiting in eager anticipation.

 

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Tags: Real-time Communications, WebRTC, Networking