The Constrained Directional Enhancement Filter in AV1 | Hacker News Reader

The Constrained Directional Enhancement Filter in AV1

hacks.mozilla.org

151 pointsKwanEsq24 comments

The author, monty, is an inspiration for his ability to patiently break down and explain deep topics. It's a rule that every time something of his hits HN someone must post a link to the following video of his, as a benchmark of quality for other technical presentations: https://xiph.org/video/vid2.shtml

I saw the title and thought "I hope it's by monty", then I saw the domain and was a bit sad, then I clicked and it was a miracle!

Is that directional effect used on the Sydney harbor available as a Photoshop plugin? I like the affect it produces.

Ha, many people have asked for that :-) I jokingly suggested we should go get some VC and launch a plugin company...

there are a few PDE implemented in the G'MIC plugin that produce the same effect (anisotropic smoothing, dream smoothing)

I'm tempted to print it and put it on the wall.

Some sample videos would be nice, preferably 4K (both Firefox and Chrome support it via flags)

Update: I have There was a [youtube] [youtube] [info] Available format code 249 webm 250 webm 140 m4a 171 webm 251 webm 160 mp4 278 webm 242 webm 133 mp4 243 webm 134 mp4 244 webm 135 mp4 247 webm 136 mp4 248 webm 137 mp4 17 3gp 36 3gp 18 mp4 43 webm 22 mp4 found some YouTube videos serve AV1 when using Chrome Canary with AV1 flag set. To check, right click video > Stats for nerds

Haven't found 4K one yet...

AV1 encode times are, compared with h264, very slow. Encoding 4k video on a dual socket Xeon server of 30min in length took almost four days last time I tried. That's probably why you can't find much yet.

Yes, now with the bitstream finally frozen I'm hoping we'll see a flurry of effort in optimizing aomenc.

I'm also hoping there will be a future xAV1 encoder from the x265 developers, a while back a spokesperson for them over at the Doom9 forum said that they will go where the market goes, and from the looks of it, AV1 will eventually become the new de facto video codec on the internet (which is currently h264).

> AV1 will eventually become the new de facto video codec on the internet (which is currently h264)

As much as I would like to agree with this, I think we should expect H.264 to be the de facto codec for quite a while longer. Consider the following:

* An industry research group's 2017 survey [0] showed us that most users still only stream at 720p and that will probably not change in the immediate term. When 4K is the norm, we'll have a glaring need for AV1.

* That same Harmonic 2017 survey also showed that most distributors don't plan to leave H.264 because it is serving their needs just fine.

* x264 only got to where it is today after nearly 10 years of active development. I remember how painful it was to encode H.264 with open source tools in the beginning. Most distributors will not want to take the plunge immediately into AV1 until x264-style stability and acceptance are imminent.

[0] http://www.streamingmedia.com/Articles/Editorial/Featured-Ar...

AV1 isn't just for 4K, though. Netflix recently showed a demo of 720p AV1 at only 200kbps. It should massively improve the low end - in fact, maybe the low end first because lower resolution streams are the fastest to encode.

> I remember how painful it was to encode H.264 with open source tools in the beginning.

Worth noting that the standard encoder and decoder are open source and royalty free today.

Is the bitstream actually frozen now? weird "AV1 is there" message recently and then some comments saying, "but not really, bitstream is still not frozen". I saw several claims of bitstream freeze, but never sourced by any official statement.

As someone who's not deep into AV1, but watching interested from outside, I can say that communication is not ideal.

> As someone who's not deep into AV1, but watching interested from outside, I can say that communication is not ideal.

That former announcement was PR/Marketing only. The devs (all the ones I saw) didn't know it was coming.

Yes, the bitstream is frozen. I can't find an HTML version for some reason, but this page links to the finalized 1.0 version of the spec: https://aomediacodec.github.io/av1-spec/

As of 3 days ago... yes the bitstream is frozen (see the reference PDF)

https://aomediacodec.github.io/av1-spec/

The date in the PDF is 2018-06-25.

It seems that ffmpeg 4.0 supports av1, but only via the reference encoder. The faster rav1e encoder isn't a bundled option... ( https://github.com/xiph/rav1e )

https://www.ffmpeg.org/index.html#news

https://trac.ffmpeg.org/wiki/Encode/AV1

However that does make me hopeful that I could annotate the start delay for each track, split off the video track, and re-combine an externally encoded video stream.

How does it compare to hevc with preset veryslow? An Epyc server gets about 2FPS (but I've found it most efficient to run 2 jobs that both get about 2FPS simultaneously).

Is that comparing AV1 CPU encoding vs hardware-accelerated h.264 encoding?

Even non-hardware-accelerated H.264 encoding is very fast via the libx264 library.

"Very fast", in my opinion, means encoding good-quality (better than hardware accelerators!) 4K video faster than real-time on hardware reasonable attainable in a $1000-$1500 desktop system.

Most content isn't encoded with hardware encoders due to their rather poor performance vs. bitrate. If you don't need to do realtime encodes, using HW encoders is a huge waste of bitrate (and by extension money for bandwidth).

Any chance you have a youtube link for something with a AV1 encoding ? Haven't found anything yet myself.

Sorry, they're very likely running A/B testing of some sort, as this link was AV1 (Codecs: avc1.64002a (299) / mp4a.40.2 (140)) for me earlier, but no longer:

https://www.youtube.com/watch?v=ogfYd705cRs

avc1 is https://en.wikipedia.org/wiki/H.264/MPEG-4_AVC not AV1

The available formats for that video are:

    $ youtube-dl -F https://www.youtube.com/watch?v=ogfYd705cRs ogfYd705cRs: Downloading webpage ogfYd705cRs: Downloading video info webpage formats for ogfYd705cRs: extension  resolution note audio only DASH audio   70k , opus @ 50k, 37.58MiB audio only DASH audio   88k , opus @ 70k, 45.92MiB audio only DASH audio  136k , m4a_dash container, mp4a.40.2@128k, 98.65MiB audio only DASH audio  148k , vorbis@128k, 70.46MiB audio only DASH audio  158k , opus @160k, 95.71MiB 256x144    144p  114k , avc1.4d400c, 30fps, video only, 29.91MiB 256x144    144p  147k , webm container, vp9, 30fps, video only, 61.11MiB 426x240    240p  226k , vp9, 30fps, video only, 75.75MiB 426x240    240p  252k , avc1.4d4015, 30fps, video only, 54.98MiB 640x360    360p  413k , vp9, 30fps, video only, 140.49MiB 640x360    360p  644k , avc1.4d401e, 30fps, video only, 182.59MiB 854x480    480p  764k , vp9, 30fps, video only, 227.69MiB 854x480    480p 1193k , avc1.4d401f, 30fps, video only, 377.25MiB 1280x720   720p 1521k , vp9, 30fps, video only, 423.38MiB 1280x720   720p 2375k , avc1.4d401f, 30fps, video only, 730.12MiB 1920x1080  1080p 2674k , vp9, 30fps, video only, 810.25MiB 1920x1080  1080p 4461k , avc1.640028, 30fps, video only, 1.34GiB 176x144    small , mp4v.20.3, mp4a.40.2@ 24k, 57.43MiB 320x180    small , mp4v.20.3, mp4a.40.2, 162.63MiB 640x360    medium , avc1.42001E, mp4a.40.2@ 96k, 332.87MiB 640x360    medium , vp8.0, vorbis@128k, 452.27MiB 1280x720   hd720 , avc1.64001F, mp4a.40.2@192k (best)

Ah, my brain missed the 'c', thx for that

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