I don't know what's up with AV1 software decoding but it uses considerably more CPU than HEVC or VP9
AV1 video codec gains broader hardware support
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Re: AV1 video codec gains broader hardware support
#62Microsoft Edge does support AV1, but weirdly only through a Microsoft Store extension [1], even though Chrome has support built-in. This actually really sucks because in practice hardly any normal consumers would bother to install a strangely named extension, and so web developers have to assume it's largely unsupported in Edge. Safari ties support to a hardware decoder, which I suppose is understandable to avoid acc…
Microsoft Edge USED to support AV1 through the extension, but decided to disable the support altogether since v116. The "Can I use" website [1] has the up-to-date information on this. [1] https://caniuse.com/av1
Huh, I didn't know that, good point! Even weirder though. Hopefully it's a prelude to built-in support.
Re: AV1 video codec gains broader hardware support
#63According to the article, it's supported by every browser except Edge. It will be interesting to see who ultimately ends up making a better IE, Safari or Microsoft. So far, it seems Safari is winning, given the ever growing set of standards they don't support, but maybe this is Edge trying to catch up?
What are the "ever growing set of standards" that Safari doesn't support?
This was discussed here not too long ago. I assume not much has changed since then.
https://news.ycombinator.com/item?id=31902707
Re: AV1 video codec gains broader hardware support
#64Earlier quoted context omitted.
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 no…
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.
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[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.
Re: AV1 video codec gains broader hardware support
#65I don't know what's up with AV1 software decoding but it uses considerably more CPU than HEVC or VP9
I wonder if it's just because it's new. I remember years ago the first 1.x versions of libopus used way more CPU than Vorbis to decode, now they're comparable. (This was on a teeny little chip where decoding 1 Vorbis stream took a measurable amount of CPU)
Re: AV1 video codec gains broader hardware support
#66What’s so special about AV1?
* No patent fees.
* Wide browser support.
* High performance open source software decode available on x64 and ARM
* High performance open source software encode available, tuned for multicore cloud encoding
* default support for film grain emulation which alone can save about 30% bandwidth when content requires it.
Re: AV1 video codec gains broader hardware support
#67Earlier quoted context omitted.
Only decode, not encode. Intel ARC GPUs also do encode.
I think it makes sense for companies to start with decode though. That hits pretty much 100% of users--everyone watches video. But only a small fraction of users actually create content and need accelerated encode. And Apple especially I think is unlikely to use AV1 for their video recording, given their investment in other formats for that use-case.
Plus unless you are streaming or producing a ton of video most users can afford to wait a bit for software encoding (which is often better quality as well). So encoding is far less important than decoding.
Re: AV1 video codec gains broader hardware support
#68Microsoft Edge does support AV1, but weirdly only through a Microsoft Store extension [1], even though Chrome has support built-in. This actually really sucks because in practice hardly any normal consumers would bother to install a strangely named extension, and so web developers have to assume it's largely unsupported in Edge. Safari ties support to a hardware decoder, which I suppose is understandable to avoid acc…
> ...which is why I've proposed support for AV1 and Opus for the Interop 2024 effort...
A very nice initiative!
Feels like we've been lagging behind on development in this area for some time. And with a wider support (in both hardware and software) more actors should be able to enter this field in the future.
I really hope this gets enough traction in a near future!
Re: AV1 video codec gains broader hardware support
#69How much silicon does it take to add an AV1 decoder to a chip? The areas Apple highlighted in their A17 release looked pretty substantial, but I wasnt sure if it was to scale. https://b3148424.smushcdn.com/3148424/wp-content/uploads/202...
That looks like a pure marketing slide to me. I don't think it would make sense to actually have separate dedicated silicon for these.
Re: AV1 video codec gains broader hardware support
#70Is it really _that_ hard to create a generic video decoding DSP whose firmware could be updated? Most codecs are very similar to each other. IIRC Texas Instruments used multicore DSP to decode MPEG back in the 90s. Or maybe we should have written codecs to be amenable towards GPU shader implementation...
> Or maybe we should have written codecs to be amenable towards GPU shader implementation...
They are, but programmable GPU shaders are nearly always more power expensive than fixed function purpose specific silicon. It's why many key aspects of GPUs are still fixed function, in fact, including triangle rasteriziation and texture sampling/filtering.