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Old 13th January 2012, 18:01   #1  |  Link
iwod
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x265 - Work already started?

http://code.google.com/p/x265/

https://github.com/chenm001/thevc

I was wondering why it isn't based or branch off from x264. Are they starting from scratch?
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Old 13th January 2012, 18:05   #2  |  Link
poisondeathray
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There is a blog link on the google page, but it's in chinese

http://chenm003.blog.163.com/

There seems to be only 1 author/contributor ? Where are the other "usual suspects" ?
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Old 13th January 2012, 18:07   #3  |  Link
LoRd_MuldeR
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Doesn't look like the "x265" project you are linking to is created by the people who created x264.

Also it's under an BSD license, which means they can't take any code from x264, which is under the GPL:
https://github.com/chenm001/thevc/blob/master/COPYING

(There is no "Copyleft" in the BSD license, which is an important idea of the GPL, so they are not compatible)


Finally we need some prove for those claims:
Quote:
Simple and powerful HEVC/H.265 implement.
Optimize for embedded, FPGA, GPU, MultiCores system.
Given that h.265/HEVC has not even been officially released (scheduled for January 2013), I doubt their implementation is complete or even optimized yet

(Maybe that implementation is based on an early draft version of h.265/HEVC)
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Last edited by LoRd_MuldeR; 13th January 2012 at 18:14.
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Old 13th January 2012, 18:09   #4  |  Link
poisondeathray
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Wouldn't it be a better idea to join forces ??

What are the x264 dev's thoughts ?
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Old 13th January 2012, 18:32   #5  |  Link
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Update: Actually it appears that "x265" and "thevc" may be two different projects, just the x265 author is working on the latter too.

(So forget about my comment about the license issue, as x265 actually is GPL'd)
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Old 13th January 2012, 19:32   #6  |  Link
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think the final draft of HEVC/H265 is out next month.
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Old 14th January 2012, 09:08   #7  |  Link
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Its kind of cheeky and a little deceiving to be using the name x265 if the projects are completely unrelated, because it would be human nature to expect it to be from the same authors and to the same quality as x264...

h265 is a long way off yet, as its target is a 50 percent improvement in the compression vs size. This is achievable, but requires large amounts of CPU. Also no point if the standard encode settings (and use for transmission) of h265 isn't much better than h264 for the same CPU usage. If you encode on tight x264 settings and the resultant size is say, 500MB, and you compress in h265 to the same CPU usage (may be low settings) and for the same quality its 500MB or larger, its a bit of a disadvantage.

That aside, to get 50 percent better than h264 it may encode at 0.17 fps compared to the 100 percent larger h264 (using x264) encoding at 25fps...

A note on the percentages above, seeing people online often misinterpret or incorrectly state percentages:
h265 half the size, is 50 percent better. Since its half h264, you need to double it to get back to h264 size, meaning 100 percent larger.

Processing requirements of h265 for its target size etc is one reason why it hasn't been released yet. Little point releasing something unusable that can be possibly improved if delayed . h265 is probably the logical choice for future Ultra High Definition Television (UHDTV) transmission and distributable media (blu-ray etc), since its 76804320. It would also be the logical choice for Quad Full High Definition (QFHD) 38402160 if thats the future resolution instead of UHDTV.

Probably wouldn't have been a bad idea for these people to work on x264 and use what they can from it once the standard is released. At the moment, they could do a whole heap of work on h265 only to find they have to redo the whole lot if the standard changes before releasing :S

Last edited by burfadel; 14th January 2012 at 09:11.
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Old 14th January 2012, 11:31   #8  |  Link
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i'm sure fixed function hardware will make h265 fast to encode, just look at the speed of quicksync encoding and ati's upcoming equivalent. I'm sure ARM chips will be able to do it too but existing chips will indeed be very slow i'm sure. Hopefully existing hardware decode cpu/apu's might be able to add support to hardware decode h265 but can't see them being able to hardware encode h265.
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Old 14th January 2012, 12:17   #9  |  Link
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Quote:
Originally Posted by hajj_3 View Post
Hopefully existing hardware decode cpu/apu's might be able to add support to hardware decode h265
Not possible with current hardware. Most likely it will take a couple years before hw decoders start popping up in GPUs and other generic consumer devices. The format needs to be adopted widely first.
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Old 14th January 2012, 17:38   #10  |  Link
iwod
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Well we can do the decoding with special Hardware. All Mobile Devices will force this to happen compared to previously they all try to use the CPU as much as possible.

Since UHDTV will have 4 times the pixel compare to 1080P Full HD, i wonder would 50% reduction be enough?
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Old 14th January 2012, 17:43   #11  |  Link
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What is the goal of H.265?
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Old 14th January 2012, 17:45   #12  |  Link
LoRd_MuldeR
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From Wikipedia:

Quote:
Said to improve video quality and double the data compression ratio compared to H.264., HEVC can scale from 320 x 240 pixels all the way up to 7680 x 4320 resolution.
Quote:
HEVC aims to substantially improve coding efficiency compared to AVC High Profile, i.e. to reduce bitrate requirements by half with comparable image quality, at the expense of increased computational complexity. Depending on the application requirements, HEVC should be able to trade off computational complexity, compression rate, robustness to errors and processing delay time.
We'll see how much of that will hold true

And we probably won't know until an H.265 encoder with the same level of optimizations as x264 has nowadays will be available - which can take years!

(Remember: There are enough "bad" H.264 encoders, which could easily lead to the conclusion the H.264 is worse than MPEG-4 ASP, if there weren't the "good" ones to prove the opposite)
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Last edited by LoRd_MuldeR; 14th January 2012 at 17:55.
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Old 14th January 2012, 17:48   #13  |  Link
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If no "heavy" stays behind, the fate of H.265 will look alike the one of on6 codec, or any ogg ones.
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Old 14th January 2012, 18:15   #14  |  Link
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Quote:
Originally Posted by burfadel View Post
Its kind of cheeky and a little deceiving to be using the name x265 if the projects are completely unrelated[...]
Note that x264 just applies an x letter to "h.264", most likely inspired by xvid. So continuing the tradition with x + h.265 is not particularly cheeky. It's an ambuitious name (much like x264 at the start when xvid was the choice codec), but that's it.
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Old 14th January 2012, 19:19   #15  |  Link
Dark Shikari
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There seems to be a history of projects like this. For example, there was a Chinese developer who has been (for years) spam-mailing hundreds of video codec developers with his "H.265" codec which has absolutely nothing to do with the actual H.265.
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Old 14th January 2012, 19:38   #16  |  Link
poisondeathray
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x265.nl , x265.com aren't registered domains yet . Maybe someone should register before someone makes a play
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Old 14th January 2012, 21:03   #17  |  Link
mariush
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Well, I registered x265.net now.

If Dark Shikari or one of the x264 guys want to start on x265 sometimes in the future, I'll be willing to transfer it to them for free.
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Old 27th January 2012, 19:32   #18  |  Link
iwod
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Quote:
Originally Posted by Dark Shikari View Post
There seems to be a history of projects like this. For example, there was a Chinese developer who has been (for years) spam-mailing hundreds of video codec developers with his "H.265" codec which has absolutely nothing to do with the actual H.265.
So would we get an official x265 project? Since there is now even a x262
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Old 27th January 2012, 20:04   #19  |  Link
Dark Shikari
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H.265 is quite different from H.264 in terms of structure; it'd be a pretty hefty modification.

But if someone really wants to try...
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Old 27th January 2012, 20:55   #20  |  Link
hajj_3
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i think the only real advantage to most people is smaller filesize for the same quality, 700mb files would be far smaller. I can't see that many people using this for the higher quality as it would take ages to encode i'm sure. Needless to say i'd love to see an x265 real project
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