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12th April 2018, 03:45 | #621 | Link | |
Angel of Night
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12th April 2018, 06:25 | #622 | Link |
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VP9 already had 1/8 pel MV precision, it was probably just inherited from there.
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12th April 2018, 21:23 | #623 | Link |
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Harmonic showed a comparison demo at NAB, pitting AV1, AVC, HEVC and JVET against each other. At the equivalent bitrate of 1.9 Mbps they got the following results:
Codec -- PSNR -- VMAF AVC -- 32.7 -- 58 HEVC -- 36.7 -- 80 AV1 -- 37.2 -- 83 JVET -- 38.5 -- 88 That's all the info I got. |
12th April 2018, 22:52 | #624 | Link |
German doom9/Gleitz SuMo
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They still use PSNR? Don't we prefer SSIM/dB today? Well, VMAF is more like that.
What does it prove? ... More computational complexity is the solution? We need more supercomputers. This statement might contain sarcasm. Last edited by LigH; 12th April 2018 at 22:55. |
14th April 2018, 12:39 | #625 | Link | |
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14th April 2018, 13:14 | #626 | Link |
German doom9/Gleitz SuMo
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For this one selected sample, maybe? Many show demos pick the one comparison with the results making the own preferred product look best. I do not even see any link to this show here (maybe colinhunt was there in person?).
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16th April 2018, 10:46 | #629 | Link | |
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16th April 2018, 17:14 | #631 | Link |
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enctac for Vp9 in comparisons I recomend to disable frame-parallel as is at outdated feature and use row-mt because in my tests it don't hurt quality and inprove speed (in reality row-mt has highther metrics but the variation is so low that statistically is insignicant, it has a variance of 0.0002 for ssim scores and 0.04 for vmaf scores). Plus apart of CPU 0 is also interesting to use CPU 1 an least one time in the comparison.
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16th April 2018, 23:35 | #633 | Link |
German doom9/Gleitz SuMo
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As usual, it is impossible to give a guaranteed ratio of efficiency between two codecs, it always depends on the material processed with it, as well as how annoying a specific person rates the loss.
The development of both HEVC (x265) and AV1 is not yet done, and AV1 is in a much earlier stage (it has not even many speed-up techniques implemented yet). But it is already considerably more efficient than x265. Unfortunately, it also requires a lot more time to encode. |
17th April 2018, 09:05 | #635 | Link |
German doom9/Gleitz SuMo
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At its current speed, I don't have the patience to run elaborate test sequences, they would probably take months without using a "render park".
And how much difference does it mean to you whether it is 10% or 15% or 20%? Where is your personal threshold for ... which action? |
17th April 2018, 14:38 | #637 | Link |
German doom9/Gleitz SuMo
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Because AV1 software is not yet mature enough, neither as encoder nor as decoder. If you have a device which has a hard time playing FullHD HEVC and can't handle UHD HEVC in real time, then do not even consider trying to play AV1.
The AOM is just even in the process to release specifications. There was no time yet to speed-optimize any software implementation. And without specifications being officially finalized, no hardware producer would be a fool to already release accelerating decoder chips. |
17th April 2018, 17:58 | #638 | Link |
Derek Prestegard IRL
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Clearly a very long way to go.
Development of psy is of course critical in getting good subjective quality. In the tests I've seen the encoder still favors blurring heavily which smells a lot like simple PSNR tuning Also, hopefully AV1 avoids the pitfall of VP9 - terrible rate control. Provided these issues are handled, the encoding speed comes up and fast software decoders plus hardware decoders come out, I'd see AV1 being quite useful on the web - specifically in Chrome and Firefox, since these will likely never get HEVC support. As a premium OTT service operator, I struggle to see the value in it, however, since DRM standards only allow for delivery of 480p (and in some cases 720p) on Chrome and Firefox due to the insecurity of Widevine on these platforms. One of the biggest value propositions for using a new codec is being able to deliver high resolution video. If my DRM requirements prevent this, there's less incentive to spend the cost to make yet another video format. The way I see it, we'll have to keep making H.264 basically forever, we have to make HEVC today to deliver UHD + HDR video to all the 10 foot endpoints plus some mobile devices, and that is an increasingly mature ecosystem with high quality today. VP9 is an option, but it's moot for us since everything that supports VP9 also supports HEVC, and practical HEVC encoders are better than libvpx. What does adding AV1 get me? |
17th April 2018, 18:32 | #639 | Link | |
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My Personal Opinion, judging from small amount of testing and limited information, AV1 is the same or ( 10 - 20% ) better. ( Bitrate Reduction ). That is at the expense of 500x to 1000x+ encoding time. And as said, AV1 encoder is not optimised for speed yet, expect the final to be around 6 - 10x encoding time. |
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17th April 2018, 22:19 | #640 | Link |
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Look closer (--cpu-used=2 and --cpu-used=1).
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