Page MenuHomePhabricator

Study the compression performance of single-frame AV1
Closed, ResolvedPublic


AVIF is the first proposal to become the equivalent of WebP (single-frame WebM) for AV1. If the claims I've heard are true (half the size of equivalent JPGs), something like this will inevitably appear.

Having some benchmarks of how well single-frame AV1 performs compared to JPG or WebP of the same visual quality is not only good blogging material, it could also drive browser vendors to work on something like this.

While AVIF has been proposed, WebP itself is extensible and AV1 could very well become a new codec WebP supports.

Event Timeline

Gilles triaged this task as Medium priority.Dec 11 2018, 9:40 AM

I've figured out a way to test this with the latest ffmpeg and libaom, and holy crap the hype is real. When I hit the same DSSIM fidelity for the AV1 "thumbnail" as the JPG and WEBP ones from production, I get the following. Note that the embedded images in this comment are lossless PNG conversions of the actual thumbnails, provided here to eyeball visual differences.


400px-President_Barack_Obama.jpg.png (500×400 px, 279 KB)

850 + 538 = 1388 bytes of metadata (JPEG APP1 + JPEG APP2, includes ICC profile)

Total file size: 50702


400px-President_Barack_Obama.jpg.webp.png (500×400 px, 286 KB)

844 + 524 = 1368 bytes of metadata (RIFF ICCP + RIFF EXIF)

Actual bytes of image data: 36426

Total file size: 37848


400px-President_Barack_Obama.jpg.av1.mkv.png (500×400 px, 317 KB)

No metadata. The absence of the color profile should be without incidence for the pixels compared via DSSIM, as we're talking about the default TinyRGB profile.

A proper AV1 image container would include both EXIF and color profile. In fact WebP is extensible and could contain AV1-encoded data. Knowing that, I'm going to assume that the real AV1 image would contain the same size of metadata as the webp thumbnail.

Actual bytes of image data: 23796

Approximate total file size of AV1 image if it was stored inside a WebP: 37848 - 36426 + 23796 = 25218


WebP is 25% smaller than JPG (this is the typical kind of ratio we've seen for lossy WebP). AV1 is 33% smaller than WebP and 50% smaller than JPG! This is exactly the figure Kornel Lesiński claimed in his talk at

Now time to turn this into a blog post...

Emailed the 2 Google engineers who wrote most of the WebP container spec about the idea of extending WebP to allow AV1 as a codec to encode frames. One of them seems to be working on AV1 anyway. Based on the spec, it seems like a very straightforward thing to do, and Chrome already has AV1 decoding for video.

I might wait for their response before sending the blog post I'm going to write to the perf calendar.

Will post blog post soon, either on the perf calendar or our own blog if it doesn't get picked up for that.

JPEG XL supports mathematically lossless from JPEG convertion and back and also better than AVIF. Soon to be added in Chrome.