Dav1d - the fastest AV1 decoder now in Firefox by default

Original author: Nathan Egge
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Intro by Voximplant

Yes, this is not the first time we are writing about AV1 - we already had a translation about Chrome 70 with codec support , and here we are again sharing the news. This time, the word is Nathan Egge, a senior engineer at Mozilla and a member of the Xiph.org foundation, who was pleased with the news about default support for AV1. It is difficult to overestimate the importance of this codec for modern streaming services, as well as for a real-time application for audio / video communications. Why dav1d, how it differs from the first AV1 decoder, a few graphs from benchmarks and a forecast for the future - briefly and on business, I ask for cat.

The release of Firefox 67 has improved performance so much that the 67th version is faster than all previous ones. Among the improvements is the free dav1d AV1 decoder , which is now on by default enabled on all desktop platforms (Windows, OSX and Linux) for 32- and 64-bit systems.

With files that are 30% smaller than the most popular VP9 web codec and almost 50% smaller than the files of its predecessor, H.264 , the AV1 codec gives better quality with less network load, and can also potentially change, like where we watch videos online.

However, since AV1 is a new and more sophisticated codec, some experts predictedThat its distribution on the market will wait until 2020, when the appearance of high-performance decoders is expected. The Dav1d built into the browser refutes these predictions.

Supported by the Alliance for Open Media (AOM) , dav1d is a collaboration between the French nonprofit VideoLAN and the open source community FFmpeg (by the way, FFmpeg already somehow made a decoder that was faster than the original, it was FFvp9 for VP9 - approx. Translator) . The best minds of multimedia open source have joined forces to release the first version of dav1d last fall, which was immediately 2-5 times faster than libaom , a decoder from AOM, which was part of the AV1 standard.

Since then, developers have squeezed even more performance out of dav1d by categorizing and rewriting critical sections in a highly parallelized SIMD assembly. And this can be seen in the benchmarks:

Higher performance and efficiency mean smooth playback of AV1 video in a browser with a noticeable reduction in CPU load.

AV1 is already used on the web

The appearance of dav1d in Firefox happened more than ever in time. Only in recent months have we noticed a significant increase in the use of AV1; According to our data, in April 11.8% of videos in Firefox Beta were played using AV1, while in March this figure was around 3%, and in February - 0.85%.

Given that dav1d is built into desktop Firefox, we expect that even more websites will use the next-generation free codec - AV1.

Mozilla is investing in the future of AV1

Modern decoders like dav1d are great for playing video, but solid, free and open source encoders are also very important for the AV1 community. The original encoder from AOM was designed to design the AV1 standard, rather than making an encoder for production. Therefore, Mozilla and Xiph.Org are jointly developing a “sterile” rav1e encoder (Rust AV1 Encoder) so that it has advantages over the original encoder and allows sufficiently fast software coding for real-time applications (for example, WebRTC applications).

Good coders rely on psycho-visual models to highlight bits for what human perception evaluates as “good quality” (not PSNR) With rav1e, we will use the perceptual analysis competencies from our earlier designs - Daala and Theora - to add masking activity , better color balance , better control of bit rate and perceptual distortion metrics like CDEF . All this will lead to a new level of quality for AV1 encoding.

We are also making significant efforts to increase the encoding speed, applying techniques that first appear only in AV1. It’s not enough just to rewrite the existing source encoder code in the SIMD assembly and make it 4 times faster. Rav1e offers ways to make AV1 encoding 1000 (one thousand) times faster using new algorithms rather than optimizing existing code.

Rav1e is constantly getting better and better. Active development will continue at a high pace to roll out major changes weekly.


  1. AV1 beats x264 and libvpx-vp9 in practical use case - code.fb.com
  2. MSU Codec Comparison 2018 - www.compression.ru

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