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Comment by dannyw | Hacker News Reader

Is AV1 better than HEVC? Or is it about the same, just freely licensed?

We have to make a distinction between the standard and implementations. AV1 has open source implementations which achieve really high compression. HEVC also has implementations which achieve really high compression and do that faster than AV1, but all the good ones are paid like MediaConcept. [1] The open source HEVC implementations (i.e. x265) are unfortunately quite weak compared to their AV1 counterparts and do not achieve comparable compression.

So yes, the answer depends most on whether you care about licensing. Both in terms of royalities and also implementations.

[1] https://www.mainconcept.com/hevc - for the casual user most easily accessed by purchasing Adobe Media Encoder

Very insightful, but is x265 really that bad? If you’re willing to wait, does slower presets help?

I tested NVENC, X265, and DaVinci Resolve Studio’s H265 encoder.

x265 was best by far. What more am I missing on?

Yes x265 is not in the conversation for even top 5 HEVC encoders, regardless of presets. [1] It can be especially surprising because x264 is easily the best AVC encoder. For whatever reason (patents, lack of browser support etc) there just hasn't been as much engineering effort put into x265.

Now things like NVENC are even worse in terms of compression. Any GPU accelerated encoder trades compression efficiency for speed. Even x265 with the slowest presets will demolish any GPU encoder in terms of compression, including the MainConcept paid one when it's run in GPU-accelerated mode. This is unfortunately not explained in GUIs like Adobe tools. They just have a checkbox or dropdown to select GPU acceleration, but don't mention that it's not just acceleration - a different algorithm will be used that can't achieve the best compression.

GPU accelerated compression can still be very useful for scenarios where you need speed (e.g. have a deadline) or just don't care about quality (e.g. will publish it only on social media where it will be recompressed anyway). However when you have time to wait and want top quality, the slowest CPU-only code path will always win.

[1] One good public resource is the Moscow State University page http://www.compression.ru/video/codec_comparison/index_en.ht... -- They do regular comparisons of various codecs and some results are available for free. A bit in HTML form and more in some of the PDFs. Deeper insights are unfortunately paid.

Are there any CPU+GPU pipelines that improve the speed without decreasing quality to the level of current GPU-only algorithms?

Seems strange that we have so much compute power in GPU, but no algorithms to use it well for encodes

"GPU encoders" don't use the GPU themselves (shader cores), they use another tiny CPU attached to the GPU. GPGPU does not really help with compression much.

HEVC isn't widely supported by web browsers: https://caniuse.com/hevc

AV1 is supported by almost all web browsers: https://caniuse.com/av1

Notable exceptions are Safari and Safari on iOS (unless you have an iPhone 15 Pro).

Or an M3 Mac.

Most of those browsers are just skins over the Chromium engine.

And iOS Safari is arguably the most important browser at all since iPhones are disproportionally used amongst video content creators.

HEVC is great for giving you quality in a smaller file size, for your local video files (due to being supported by more cameras and phones so far). AV1 has wider support for streaming video online at a higher quality (due to more browser support so far). So, at the moment, they are really best in two different use cases (subject to change, of course).

> HEVC is great for giving you quality in a smaller file size, for your local video files.

This is a huge plus in fansub anime scene. 10 years ago, majority of anime are in H264 (720p/1080p 8bit) which is normally 1±GB for each episode that are consist of 25 min. If I want to watch one anime, it will consume about 20 GB of space. Now, majority of them are in HEVC (1080p 10bit) which are about 300± MB for each episode.

If you actually look up AV1 releases like Trix, the file sizes are even smaller, while keeping up the same quality.

I don't think you can reduce the comparison to "better than," but AV1 certainly compresses to smaller files than HEVC. Maybe that's a better fit for your use case.

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