Inspired by the recent news of AV1 hardware encoding support from Intel, I decided to look into the state of AV1 on Linux today. AV1 is a free and open standard as defined by Digistan without any royalty payment requirement, unlike its much used competitor encoding H.264. While looking, I came across an 5 year old question on askubuntu.com which in turn inspired me to check out how things are in Debian Stable regarding AV1. The test file listed in the question (askubuntu_test_aom.mp4) did not exist any more, so I tracked down a different set of test files on av1.webmfiles.org to test them with the various video tools I had installed on my machine. I was happy to discover that AV1 decoding and playback worked with almost every tool I tested:
| mediainfo | ok |
| dragonplayer | ok |
| ffmpeg / ffplay | ok |
| gnome-mplayer | fail |
| mplayer | ok |
| mpv | ok |
| parole | ok |
| vlc | ok |
| firefox | ok |
| chromium | ok |
AV1 encoding is available in Debian Stable from the aom-tools version 1.0.0.errata1-3 package, using the aomenc tool. The encoding using the package in Debian Stable is quite slow, with the frame rate for my 10 second test video at around 0.25 fps. My 10 second video test took 16 minutes and 11 seconds on my test machine.
I tested by first running ffmpeg and then aomenc using the recipe provided by the askubuntu recipe above. I had to remove the '--row-mt=1' option, as it was not supported in my 1.0.0 version. The encoding only used a single thread, according to top.
ffmpeg -i some-old-video.ogv -t 10 -pix_fmt yuv420p video.y4m aomenc --fps=24/1 -u 0 --codec=av1 --target-bitrate=1000 \ --lag-in-frames=25 --auto-alt-ref=1 -t 24 --cpu-used=8 \ --tile-columns=2 --tile-rows=2 -o output.webm video.y4m
As version 1.0.0 currently have several unsolved security issues in Debian Stable, and to see if the recent backport provided in Debian is any quicker, I ran apt -t bullseye-backports install aom-tools to fetch the backported version and re-encoded the video using the latest version. This time the '--row-mt=1' option worked, and the encoding was done in 46 seconds with a frame rate of around 5.22 fps. This time it seem to be using all my four cores to encode. Encoding speed is still too low for streaming and real time, which would require frame rates above 25 fps, but might be good enough for offline encoding.
I am very happy to see AV1 playback working so well with the default tools in Debian Stable. I hope the encoding situation improve too, allowing even a slow old computer like my 10 year old laptop to be used for encoding.
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