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Netflix Finds x265 20% More Efficient Than VP9 (streamingmedia.com)
Reader StreamingEagle writes (edited): Netflix conducted a large-scale study comparing x264, x265 and libvpx (Google-owned VP9), under real-world conditions, and found that x265 encodes used 35.4% to 53.3% fewer bits than x264, and between 21.8% fewer bits than libvpx, when measured with Netflix's advanced VMAF assessment tool. This was the first large-scale study to use real-world encoder implementations, and a large sample size of high quality, professional content.A Netflix spokesperson explained why they did the test in the first place; "We wanted to understand the current state of the x265 and libvpx codec implementations when used to generate non-realtime encodes optimized for OTT use case. It was important to see how the codecs performed when testing on a diverse set of premium content from our catalog. This test can help us find areas of improvement for the different codecs."
I just want websites to use the HTML5 video player as opposed to Flash. x265 is not very important except for 4K content and mobile phones. It will, though, eventually become the standard.
"Why is it that as companies get bigger, they get less competent, despite having hired more of the competent people?"
Maybe it's the increased number of levels of management and the inherent increase in distance between any two levels of management.
However, Google decided to incorporate VP10 into AOMedia Video 1 (AV1). The AV1 codec will use elements of VP10 as well as the experimental formats Daala (Xiph/Mozilla) and Thor (Cisco).[72][73] Accordingly, Google has stated that they will not deploy VP10 internally or officially release it, making VP9 the last of the VPx-based codecs to be released by Google.[74]
This is not the case of video codecs.
Video is a huge bandwidth hog and small improvements can really make a difference. This is why we still use JPEG and MP3 but video benefits from the latest technologies. It is also why Vorbis (audio) is much more successful than Theora (video). Both are patent-free formats from xiph.org.
Additionally, with hardware improving, more advanced compression algorithms can be used. For example entropy coders are mostly a performance/ratio tradeoff and newer standards tend to use more advanced schemes. Not that these couldn't have been used before, but the hardware requirement were too steep at that time. And you can't really put "insert preferred encoding scheme here" in your standard to make it future proof, because it wouldn't be a standard. All parts have to work together. You don't want to specify a super duper filter that melts CPUs and botch the job with a crappy entropy coder, you have to balance each part to get the best of your target hardware.
You realize we're comparing a FREE option vs a PAID option. As a business trying to save money here/there, I'd rather go with the free one to be honest.
Additionally, the title of this post is a bit misleading for what Netflix actually found. h.265 was better than VP9 in 4K content, but when it came down to 1080p and lower resolutions, VP9 did just as good or better than h.265. 1080p will STILL rule the streaming market for the foreseeable future, so VP9 is definitely relevant here.
Quote from Netflix on their blog regarding this:
Here’s a snapshot: x265 and libvpx demonstrate superior compression performance compared to x264, with bitrate savings reaching up to 50% especially at the higher resolutions. x265 outperforms libvpx for almost all resolutions and quality metrics, but the performance gap narrows (or even reverses) at 1080p.
http://techblog.netflix.com/20...
Well that AV1 codec will have a much higher chance for success as more industry partners are involved, and it will get better hardware decoding support (both by the vendors, and by the codec itself being designed in a way with hardware decoding in mind). Netflix is part of AOM as well. The only bigger company of significance which is _not_ member of AOM is apple, who suprise suprise sits at the MPEG table and makes bucks with their H.265 patents.
You must be referring to an article on Toms Hardware. The journalist was referring to the same Netflix study, but he was confused by the results, and he jumped the gun. He changed his title the next day. In the Netflix study they used x264 and x265 settings that are optimized for visual quality, and they also did test encodes with settings optimized for PSNR measurement. But then Netflix actually published results of PSNR measurements using the visual quality optimized encodes, which are not meaningful results. On these results, for 1080P content, VP9 appeared to be slightly better than x265. What matters most with video encoders is the actual visual quality they can produce at any target bit rate. Objective measurements like PSNR and SSIM don't correlate strongly with human subjective visual quality testing. Netflix sponsored development of a new visual quality tool, VMAF, which correlates with human subjective testing much more strongly. With VMAF, Netflix showed that x265 produces identical quality to VP9 at ~ 20% lower bit rates.
I have noticed that x265 requires much more CPU for encoding AND decoding than x264. For example, my slightly aged laptop will not handle playing my 1080p x265 streams.
All these codecs allow you to choose the bitrate, so efficiency is meaningless without a common basis for comparison. In this case it turns out they mean efficiency at the same video quality. But video quality is a completely subjective thing - how can you compare it in a reproducible manner? So I dug into how Netflix is deterministically measuring something subjective. That in itself is a pretty fascinating read.
tl;dr - they took subjective test results from showing video samples to people, then used machine learning to develop an algorithm which produced similar results.
That's pretty shortsighted, even for a business. If you factor in the bandwidth costs of delivering 20% more data, using the paid CODEC might actually make better financial sense.
Speaking of which (HTML5 Video and Netflix):
The IETF has a working group to produce a new gen video codec "NetVC" (Designed to be easy for wide adoptions, as the previous efforts of the IETF like Opus for audio).
The main candidate is by a group called "AOMedia" (association for openmedia), working on AV1 (AOMedia's Video codec 1).
The association includes:
- Google (of Youtube fame) : They are using their current development as a base for AV1 (what would have become VP10 if there wasn't this whole NetVC story).
- Xiph (of Vorbis and Opus fame, with also contributions toward Flac, Speex, etc.) : They are developing a very interesting project called Daala, and they ended up also contributing the innovation done for Daala into AV1.
- Cisco : They gave what they have developed for their Thor codec also into AV1.
Netflix has also joined the AOMedia and they are investing resources into it.
Same with several browser makers (including Mozilla).
With all the people involved:
- you know there's some interesting performance coming (given the brains involved here, given past successes like Opus, and given the promising results of research projects like Daala).
- given that 2 top content providers like Google (Youtube) and Netflix are on board, there's a high chance of seeing deployment of the new codec.
- given that browser makers like Google (chrome), Mozilla, and Microsoft (Edge) are on board, there's a high chance of seeing browser support for the new codec.
- given that hardware chip maker like ARM, Intel, AMD, Nvidia, etc. are on board there's going to be hardware decoding support.
(Adobe is on board too, so browser support is guaranteed for the Widevine DRM plug-in required by Netflix' licensors. Not that it matters that much, because that part of HTML5 Video is already defined and deployed everywhere, except maybe with Firefox on Linux which is a bit delayed)
But you know that this looks promision,
and maybe same time next year, we'd be reading summaries along the lines of "Netflix and Google find AV1 20% more efficient than HEVC/H.265" "And also cheaper, royalty-free and widely supported"
"Sufficiently advanced satire is indistinguishable from reality." - [Tips: 1DrYakQDKCQ6y52z6QbnkxHXAocMZJE61o ]
It's also a tyranny of "good enough". Seriously when a 40mpxl image comes down as a 10MB JPEG and look identical to any better format it really doesn't make much of a difference. Doubly so that most images are not 40mpxl.
Video on the other hand is not yet good enough.
A small nitpick, but sad to see a common but serious maths error in a technical article.
20% fewer bits is not equivalent to 20% more efficient, but 25% more .
Efficiency would be the reciprocal of the bitrate. A ratio of 4:5 becomes 5:4 when looked at the other way around.
If you were to halve the bitrate, it would be twice as efficient, not 50% more.
Or to put it in simple money terms, its like if two items are $100, one gets a 20% discount to $80, the other is now 25% more expensive.
I didn't know about this, so researched and found this page that explains "10-Bit H.264".
I offer it here so that someone can complain that I am karma whoring.
I come here for the love