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20th July 2017, 23:46 | #261 | Link | |
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21st July 2017, 07:15 | #263 | Link |
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New still image formats have just never taken off, and I doubt any will for quite a while. Most people are content with JPEG, especially due to it being supported by everything everywhere, and if you want quality you just go PNG.
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27th July 2017, 14:37 | #264 | Link | |
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The problem with a new image format is that if it can't do everything the previous ones do it won't succeed. HEIF seems extensible as well as containing pretty much every feature I can think of. WebP on the other hand was rushed and did not have too many benefits over jpeg/png (not to mention being stuck with VP8 as compression codec). |
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27th July 2017, 17:26 | #265 | Link |
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Yeah, Apple support for HEIF is a big deal, honestly. Lots of iOS apps will start using it internally to save bandwidth I'm sure - especially bandwidth hogs like facebook, instagram, snapchat, reddit, etc...
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27th July 2017, 17:41 | #266 | Link | |
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Also, Apple support means a LOT for an image format, given the overrepresentation of Macs in the creative and web design community. HLS was a bad technology, and Apple's support made it extremely widely used. Apple's support of a really good format is going to be a big deal. HEIF AV1 would be ballpark equivalent. However, the lack of HW decoders relative to HEVC could add friction for using AV1 instead of HEVC, particularly in mobile devices, Smart TVs, and other non-PC devices. |
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27th July 2017, 23:27 | #268 | Link | |
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I found this interesting paper comparing HEVC HM and VP9 for intra-coded images, looking how different features impact efficiency. It's just PSNR based, but that is fair as HM and VP9 are both heavily tuned for optimizing PSNR. http://www.m-hikari.com/ams/ams-2013...7-140-2013.pdf This looks interesting as well: http://www.uta.edu/faculty/krrao/dip...eport_0508.pdf I wouldn't want to extrapolate how AV1 would compare from these, of course. |
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27th July 2017, 23:41 | #269 | Link |
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my biggest problem with these papers is that they are pretty old and the encoder software made huge gains over the time up to this date.
only a new test can give a better idea how well they perform today. ok this is about intra coding right now but i wouldn't be so sure anymore if VP9 can't beat HEVC. |
30th July 2017, 15:30 | #270 | Link | |
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That said, in my tests on intra-only cases, I have found that libvpx does indeed under-perform (in my tests by approximately 10%) versus HEVC encoders in any metric. I believe this makes sense, given per-symbol adaptivity in CABAC versus global fw/bw adaptivity in libvpx (which - for intra-only cases - accounts for 5-10%) and less intra prediction angles (which - according to 2nd paper - accounts for approximately 5%). The rectangular block sizes for intra, decomposed ADST/DCT combinations and ADST at larger transform sizes for VP9 gives a few % points back to VP9, but not enough to make up for this. Therefore, I'm willing to give the second paper the benefit of the doubt that it may be sensible (although results are still bigger than what I see in my tests). I think the first paper is bogus. Obviously these are time snapshots and since then, x265/libvpx would both have seen improvements. Note again that this is intra-only. In inter coding, you will see AMVP (HEVC), filtered predictors (VP9) and entropy retention (VP9) making big differences. I believe entropy retention is by far the biggest one, and is the cause that as the keyframe interval increases, VP9 (libvpx) not only matches, but even overtakes HEVC in efficiency. This is obviously limited to VoD use-cases only, and cannot be used for RTC use-cases, so it also acts as an indication of particular cases where HEVC or VP9 would be more useful. And I haven't talked about coefficient coding efficiency yet - the coefficient coding in HEVC is optimized for parallelization and hardware implementability, but the other side of the coin is that its compression performance is not so great. As a result, at higher bitrates, you tend to see HEVC suffering. I'm not sure anyone cares about this for internet VoD, though... |
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31st July 2017, 17:57 | #271 | Link | ||||
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I haven't seen real-world cases where x265 doesn't have a bigger advantage over libvpx with interframe encoding. That is where psychovisual optimizations really start paying off, and encoder implementation>>bitstream syntax. Quote:
AV1 is more parallelizable than VP9 (loop filter can be its own thread, for example), although still less so than HEVC, where you basically get one potential decode thread per 64 pixels of height with WPP. And can parallelize P and B decoding if that isn't enough. |
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3rd August 2017, 00:04 | #272 | Link | |
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Last edited by TD-Linux; 3rd August 2017 at 00:15. |
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9th August 2017, 03:18 | #274 | Link | |
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There's a ton of people behind the AV1 alliance, but assuming that we'll get hardware decoding 1 year after the target code freeze seems optimistic to me. Maybe we'll luck out though if hardware manufacturers are preparing in advance. The other thing that might help is the large push to low power / mobile chips which would want to get the battery life advantage. I'm personally trying to hold out for AV1 hardware decoding to upgrade my laptop and tv media player, but it's been a long stretch. (I originally was going to wait for HEVC decoding but then quickly saw the AV1 train happening). A better optimistic guess is probably mid to late 2019, but lets all cross our fingers that we get it sooner. |
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10th August 2017, 13:09 | #277 | Link | |
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Being under Linux, I think I'll have to wait even longer. However I haven't seen Qualcomm being a supporter of AOM, I don't know what's it's gonna be like on the Android market. |
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30th August 2017, 16:14 | #278 | Link |
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http://www.streamingmedia.com/Articl...te-120214.aspx
Hopefully they can squeeze out a bit more than the targeted 20%. 25 would be nice and 30 really great. Last edited by bstrobl; 30th August 2017 at 16:17. |
30th August 2017, 18:57 | #279 | Link |
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https://forum.doom9.org/showpost.php...&postcount=259
from the pdf page 4 and 5 : target 40-50% and currently ( july 2017 ) 25-35% So the 20% should be here but for what complexity ? Last time I try it was < 1fps for 720p |
1st September 2017, 13:34 | #280 | Link |
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20% over HEVC is the wish of NetFlix, others can have different goals in mind.
That's not complexity - it's just the state of optimizations of the current implementation. Considering that the codec is in pre-bitstream freeze state, speed is not the focus, complexity of a coding tool however is. |
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