BBC Confirms 50% Bitrate Savings For H.265/HEVC Vs H.264/AVC (bbc.co.uk) 110
An anonymous reader writes: A research team from the BBC has done a series of tests to confirm earlier computations showing a ~50% savings in bit rate for H.265/HEVC compared to video using H.264/AVC at comparable quality. "The subjective tests used a carefully selected set of coded video sequences at four different picture sizes: UHD (3840x2160 and 4096x2048), 1080p (1920x1080), 720p (1280x720) and 480p (832x480), at frame rates of 30Hz, 50Hz, or 60Hz. The video content was chosen to represent diverse spatial and temporal characteristics, and then coded using HEVC and AVC standards at a wide span of bit rates producing a variety of quality levels." Here is the full published analysis. "The tests confirmed the significant compression efficiency improvements achieved in HEVC, verifying the results previously reported using objective quality metrics (PSNR based methods)." The team did not test against VP9, which is shaping up to be an impressive standard as well.
The only thing we need to know is: (Score:1)
What is it's Weissman Score?
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Now you can consume 4k video on your 3" screen (assuming anyone's mobile device has the grunt to decode it). :)
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I recall from several years ago when Apple released iMovie for their iDevices, that they could encode videos more quickly than their high-end, vastly more expensive Intel-based computers [appadvice.com] simply because the dedicated hardware encoder in the SoC could beat the Intel CPUs.
Re:And still unsupported just about everywhere (Score:4, Insightful)
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Flagship phones released last year should all have hardware HVEC decoders.
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"comparing" video CODEC quality is very hard... (Score:5, Interesting)
I've played in this space in a former position. Interesting lessons learned:
- PSNR is nearly worthless: An image with almost the same score can look terrible. Not all the time, but enough of the time.
- The only quantitative test I found that worked reliably was an old analog Tektronix PQA500 (lots of work to use for digital CODEC.)
- Management didn't like the PQA data (it said our product was terrible), decided to use PSNR data (product is great!)
- Customers fixed this discrepancy and product line failed spectacularly (due to video quality, surprise!)
- I never could find any published information sufficient to recreate the Tek PQA algorithm.
Re:"comparing" video CODEC quality is very hard... (Score:5, Informative)
Which, if you click through, is why the study performed subjective tests; by asking viewers to rate the quality of several videos at several bitrates on a 10-point scale in a series of tests. They found that PSNR systematically underestimated the perceived quality of H.265 (relative to H.264).
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I saw that in the paper, I was hoping someone might know something about Tek's old JND algorithm that's become known since then, or how it performs relative to SSIM or VQM in human subjective studies. Almost all the work in these spaces is patented or commercial...
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Subjective quality perception is a very weird metric. If you add high-frequency random noise, people perceive it as a more detailed image - an optical illusion causing them to interpret small-scale noise artifacts according to their expectation according to surroundings.
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Develop a widget to plug in between an HDMI cable and your TV that adds random noise.
I don't see how that would conform to the compliance and robustness requirements of HDCP. Nor do I see a market for HDCP-incompatible gear.
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You can't see because your view is impeded by a massive army of streamers
If you mean people who play video games and stream them, streamers will themselves be impeded by the coming crackdown by video game publishers on streaming the publishers' copyrighted intellectual property. It's already started with Nintendo, Capcom, Sega, and Blizzard at various points.
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How does random noise violate those requirements? If you're charging enough for the device, you can protect the output stream and still get it certified.
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In practice, the fixed costs of a company joining a particular DRM scheme raise "charging enough for the device" to such a level that production of a low-volume video processor intended to measurably degrade objective picture quality would likely be unprofitable.
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What on earth does that have to do with compliance and robustness? That's just unprofitable, not non-compliant.
I wouldn't be surprised if it banned modification (Score:2)
I haven't read the HDCP agreement myself, but I wouldn't be surprised if it forbade modification of the video signal.
Even if this is not forbidden, a DRM scheme operates on the principle that implementations are assumed noncompliant until proven compliant. The fixed costs of an equipment producer joining a DRM scheme include the cost of an audit (possibly probabilistic) of the compliance of the equipment producer's product on behalf of the scheme's maintainer. So even if it were compliant, whether a device
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I haven't read the HDCP agreement myself, but I wouldn't be surprised if it forbade modification of the video signal.
You can definitely modify the video signal - http://support.xbox.com/en-US/... [xbox.com]
Looks like there are HDCP certification services that will test your device for under $5000 (Simplay Labs). I assume they would be liable if the device was actually non-compliant.
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Yes it is. A million ways to fool it. However, SSIM is getting widespread usage, and highly regarded among all of those who hate PSNR.
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Or a GPU with h265 acceleration, which is getting quite common these days.
My phone, released in 2014, has no trouble with 1080p H.265 HEVC. The Adreno 330 GPU does it all without the CPU breaking a sweat.
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It plays fine on all tablets I have tried it on, and it plays on some of the little 40 dollar pcs they make now.
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vs H.264 yes (Score:5, Informative)
50% bitrate reduction vs H.264 sure, but not vs x264 which is the current gold standard for HQ video compression.
It's like comparing a new audio codec to the original fraunhofer MP3 encoder. LAME on the other hand is a significantly better MP3 encoder like x264 is a better H.264 encoder.
My own compression testing between HEVC and x264 show that at verty low bitrates, yes HEVC is better, but only at bitrates below what I would normally use and what I would consider "quality" encodes.
When you compare say a 10GB x264 encode of a full-length BluRay film, even 8GB for the HEVC does not provide an equal or superior copy.
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So if a crude HEVC encoder is equivalent to a very refined h264 encoder, what might a refined HEVC encoder be able to achieve given enough development?
Re: vs H.264 yes (Score:2)
Absolutely.
I have high hopes for the x265 project (development already underway) in the future.
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Additional info as to which encoders they used:
"HEVC HM Reference Software Codebase, Version 12.1. [Online]. Available: http://hevc.hhi.fraunhofer.de/... [fraunhofer.de] "
"AVC JM Reference Software Codebase, Version 18.5. [Online]. Available: http://iphome.hhi.de/suehring/... [iphome.hhi.de] "
Also, my experience with x265 encodes have been that (dark) low detail areas tend to look terrible, whereas everything else looks extremely good given the bitrate (be it high or low). I remember reading that this was a known (and non-trivial) issue i
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I was referring to an H.264 reference encoder...
Also I mentioned x265 in another comment. At this point x265 is hardly better than an HEVC reference encoder. Something you would know if you actually knew what you were talking about and have actually used these encoders and done lots of testing and comparisons.
How is describing my results from my own encoding comparisons rambling?
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I think it's safe to assume that the article is talking about reference encoders. The HEVC consortium set out to reduce bit-rate by 50% at equal quality for the HEVC standard and for reference H.264 vs reference HEVC they came out pretty close to that goal.
I was merely pointing out that if you instead compare a reference HEVC encoder or even the current "best" HEVC encoder compared to the best H.264 encoder (x264), the different in quality is negligible so far, especially for bitrates that actually yield a
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I think it's safe to assume that the article is talking about reference encoders.
Why would that be safe to assume? That is a useless comparison, and not one that would interest the BBC in the slightest.
What is far more safe to assume is that it is a comparison between their current h.264 encoding setup vs. whatever h.265 coded they would use in practice. Neither would be the reference codec.
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What is far more safe to assume is that it is a comparison between their current h.264 encoding setup vs. whatever h.265 coded they would use in practice.
I don't find that more safe to assume because if they were comparing any HEVC encoder to a non-reference H.264 encoder, i.e. a newer, higher quality H.264 encoder then their claims of 50% reduction in bitrate would not be possible.
Nobody in the encoder community has posted any sorts of encoder results with such a reduction in bitrate. What has BBC done that is so incredibly special to achieve what nobody else has?
I find it much more likely that they are comparing to a reference H.264 encoder as that would
Half the data is ten times as good (Score:2, Funny)
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I thought bittorrent was mostly used for Linux distributions?
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Pirates will be eager to adopt though. Patents are no issue for them, but bitrate is.
I have done my own comparisons (Score:5, Interesting)
I have done my own comparisons of AVC (using x264, single-thread, veryslow preset) and HEVC (using x265, disabling wavefront processing because it slightly reduces quality, veryslow preset). All 1080p video, significant because HEVC is supposed to scale to 4K better than AVC.
My conclusions:
1) x265 takes FAR longer to encode, but we knew that. Understandable.
2) When "low in bits", x265 blurs images rather than making them look blocky. This sometimes looks better but to me often looks worse.
3) x265 seems to force a denoise filter. Video is far easier to encode efficiently when denoised, so I figure this is part of the data savings. It's a bit of a cheat, however, because I can get far smaller file sizes by running a denoise filter myself for x264-encoded video.
I looked closely, for example, at Captain America the Blu-ray. Much of the detail of, e.g. car leather and grass and tree leaves is lost in an x265 encode, even at about the same overall data rate as x265/
x265 supports "--tune grain", roughly analogous to "--tune film" for x264, but it makes the video vastly larger -- often larger than x264's version, and it often looks worse. It does a better job of keeping grain, however.
My experience is very similar to many others' in forums. I had committed to switching my encoding to HEVC, but the results of my tests showed it is not ready for prime time. Some may not mind blurry ("soft" is probably a better word) video, or video that looks like it has been through a denoise filter, but I do.
This is not to say that x265 is junk. I am sure it will mature over time just like x264 had to over time. x264 started out as being not all that much better than divx, the previous generation.
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Forgot to add: I was using recent builds (about a month back) of x265.
Whenever a comparison is made, the x265 folks always say that the latest versions are much improved over whatever was used in the comparison. They may be, but they still need some work based on my tests.
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HandBrake has x265 built in.
https://handbrake.fr/ [handbrake.fr]
It has some quirks though. It's GUI based, but some of the defaults are plain stupid. Someone wanting "simple" is at risk of getting "inferior" instead.
If you want to devote the time to learning the quirks, you can export a preset for your users once you've got the settings right.
I made a simple preset to get you (and anyone else) started. MKV container, no cropping/resizing, no filters, default x265 settings (which you'll need to play with), untouched audio
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Just noticed hairyfeet's sig. Oh well.
Decided to unmask myself because nobody will see it anyway.
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I always use Staxrip
https://github.com/stax76/stax... [github.com]
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I don't understand how people produce decent encoding (using any format). But, they do exist. Download anything you like from a reputable pirate group, the x265 encoded videos simply come out significantly smaller with a similar quality. I do not pretend to be an videophile, but these groups are. And they use x265 and it comes out SIGNIFIGANTLY smaller than x264 every time.
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This is because release groups are completely, utterly clueless about video. The file size is set ahead of time. Most groups set e.g. "8GB for 1080p movie", "4GB for a 720p movie" etc. in x264. Historically speaking, these pre-selected sizes were designed to fit on different media types, such as CD, single-layer DVD, dual-layer DVD.
Few people use DVDs anymore, but most groups still make files far larger than they need to be.
I rarely download pre-made videos because of this, so haven't downloaded any encoded
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I have never seen a competent current group do that. They all encode based on quality, some full length movies come out 200M, others 900M+. Based on the content. They all come out looking good, and for 265, all come out significantly smaller than their 264 counterparts.
I used to do a lot of 480, horrible quality, but the smallest file size you could find anywhere. Now groups using 265 come out with smaller files in 720. Crystal clear, amazing video, at less then the smallest worst quality used to provide.
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2) When "low in bits", x265 blurs images rather than making them look blocky. This sometimes looks better but to me often looks worse.
Blocking is because of a limited amount of information to display data. Blurring is about adding noise. Noise is annoying.
The encoding community seems to disagree (Score:3)
I've read many many posts indicating that for low bitrate stuff, 265 is doing very well but for the higher end stuff, it's only marginally better than 265 (more like 25%)
That's an approximation, I don't recall the exact figure, but I do recall it being significantly less than 50%
This is pretty disappointing, perhaps other tweaks and improvements will be eeked out over time, but as it stands, I can't see a 3TB movies folder being recompressed to 1.5TB with the same quality at this point in time.
(I know that would be lossy to lossy and stupid, that's not the intention of the post)
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Addition of an extra channel in the space of one existing channel . Great for more branded content on existing bandwidth or spectrum.
Two times the nation building UK content to limit the impact of foreign broadcasting having an impact on traditional UK news and documentaries.
The role of video over IP considering the limitations of infrastructure going to most towns, cities, villages and its ability to support
It's just middle-out. (Score:3)
Influence of software in the displays (Score:1)
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I don't see any mention of how motion compensation and other "smart" features of the display devices influenced the perceived quality.
Probably because the BBC are smart enough to use professional monitors without any of that crap.
And even if they did, as long as the settings are the same for both showings, it shouldn't be a big problem.
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Re:Unbiased source? (Score:5, Insightful)
Not-for-profit does not mean not-with-costs.
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Umm, all the employees and in particular the leaders who draw multiple million dollar salaries?
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Do you think that is how normal for profit enterprises work????
Re: Unbiased source? (Score:1)
There seems to be this misconception that because the bbc is publicly funded it seeks to do everything "in the public interest " and generally doesn't behave like any other large corporation.
The truth as I see it at least is that there are a lot of highly paid media types with one eye on their careers who justify every decision using exactly the same metrics as the rest of the industry. The bbc news website is turning into a clickbait riddled buzz feed clone exactly because they judge success in terms of un
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The truth as I see it at least is that there are a lot of highly paid media types with one eye on their careers who justify every decision using exactly the same metrics as the rest of the industry.
Two eyes.
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It went to Eton and then it was eaten?
Re:Unbiased source? (Score:5, Interesting)
Name another media company that went out of their way to develop a patent-free media codec that was independent and competitive with other codecs of the time? (Google Dirac)
The BBC are publicly-funded, and under immense pressure to justify their funding at the moment - there's talk of scrapping the TV licence, and with it the BBC. They receive no advertising revenue in the UK at all. They only get some foreign revenue from sale of media (not even their own codecs or patents), and that goes to their commercial arm which isn't funding stuff like this.
There's no profit in them evaluating codecs, only if they then go out and build their own hardware that uses it. They didn't manage to do that with Dirac either, so why they would with this I have no idea.
All they want to know is what's best to push through iPlayer and store in their archive.
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The benefit for them is that they can reduce costs by reducing the bitrate, and claim not to have reduced picture quality. They have done it before - when HD broadcasts started they were around 18Mb/sec IIRC, but were later reduced to less than half that (average per channel, they actually balance about 18Mb/sec between two channels in a kind of VBR system). They claimed that the picture didn't suffer but it very clearly did, and it's now rather poor.
They are under immense financial pressure, and reducing b
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Erm you do realise that this isn't actually a quality reduction?
If you read up on HEVC, you'll notice it's a completely separate codec to AVC that was designed specifically to hit 50% better (higher quality same bitrate or same quality at half bitrate). AVC was the benchmark codec that it was being compared to.
So the BBC is just confirming that they hit that mark.
https://en.wikipedia.org/wiki/... [wikipedia.org]
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Switching from MPEG-2 to H.264 really is about a 50% savings. If your video looks bad at 18Mbps MPEG-2, you need better hardware. It won't look great, it's almost as much as the ATSC standard. It's not as bad as satellite TV that allocates less than 5Mbps H.264 to HD channels.
None of it's anything compared to the 20Mbps+ H.264 used on Blu-Ray.
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But if no quality reduction it is also a benefit to the user. Why stick to a patent encumbered standard when there's an alternative, just because someone is making money (which will happen with either standard)?
You can't prove a negative (Score:3)
Because the set of subsisting patents is so large that you can't prove a negative. It costs a substantial chunk of change to deploy set-top decoder hardware for a new data format. Once hardware implementing a decoder for an allegedly royalty-free format has been shipped out, patent holders can come out of the woodwork and claim that their patents apply to the new format. With a patented format, on the other hand, it's more efficient for a patent holder to just join the existing patent pool.
Re:Unbiased source? (Score:5, Informative)
The problem is, HEVC is expensive. While the MPEG-LA made h.264 the way it is by making streaming free (if the viewer doesn't pay) and offering caps to the maximum license fees, thereby encouraging big users (Cisco, Apple, Microsoft, Netflix, etc) to switch to h.264 and merely pay the cap every year
Of course, MPEG-LA wanted to encourage the switch to HEVC by offering the same terms, and several patentholders balked which is why they pulled out of the MPEG-LA pool and created the HEVC Alliance which licenses without a cap, without free streaming (they want some money per HEVC stream), meaning the money you save in bandwidth might go straight to licensing fees.
And I'm sure the BBC streams under h.264 were basically cost-free since the streams were available at no charge (granted, you paid with your TV license, but the MPEG-LA doesn't count that), so switching will create costs.
Re:Unbiased source? (Score:5, Interesting)
Right. This is why I think VP9 actually could win and become the new standard (replacing H.264).
H.265 and VP9 seem like they are definitely in the same ballpark on quality. And H.265 is heavily encumbered with patents; you have to pay royalties, and you never know what the royalties might cost in five years. VP9, on the other hand, is simply free: no royalties, no restrictions on what you may do with the video.
Even if VP9 takes a lot more CPU time to encode, and even if H.265 is slightly better than VP9, not having to pay royalties (not even having to keep track of what you do with the video!) is such a huge benefit. It seems like a no-brainer.
And Google will be making sure that all the Android phones at least will have good hardware support for VP9 decoding. VP8 never had a chance against H.264 because the hardware support wasn't there, and large companies were content to pay the capped fees as you noted.
All that's left is possible legal FUD around VP9, but even that seems pretty cut-and-dried to me. MPEG-LA tried for something like a year to find patents to put into their patent pool to extract royalties from VP8, and in the end Google gave them a one-time payment [osnews.com] of (to Google) a relatively small amount of money. Thanks to that one-time payment we know MPEG-LA won't ever come after anyone for using a VP8-derived codec, and I have no reason to think anyone would be able to prevail in court if they try it.
Given all of the above, it seems to me that VP9 is the obvious choice for the new video standard, and I kind of wonder why anyone is still interested in using H.265 and paying the royalties.
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If I recall correctly Google also held some important media-related patents from its Motorola purchase that allowed Google to just basically cross-license the H264 patents, the small
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the money you save in bandwidth might go straight to licensing fees
+1 Nailed it. And since bandwidth always increases while license fees usually do not decease, the deal gets worse the longer you play this game.
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Name another media company that went out of their way to develop a patent-free media codec that was independent and competitive with other codecs of the time? (Google Dirac)
There is nothing royalty-free about HEVC [wikipedia.org].
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What does that have to do with Dirac?