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19th October 2020, 18:15 | #2301 | Link | |
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YouTube also has much lower quality expectations than premium content, so they can get away with consistently suboptimal encoding. One people are paying for a service or content, their expectations go way higher. The general expectation is to not have any distracting artifacts. When someone is paying extra to subscribe to or buy UHD or HDR content, expectations go even higher. YouTube being free can cut a whole lot of corners. Pretty much all video game footage on YouTube has painful artifacts, for example. Encoding AV1 at high-quality while at low enough bitrates to justify adding another encoding target is slow. If one's willing to spend that amount of time to make AV1 look good, one could also do x264 --preset placebo and x265 --preset veryslow. One of the biggest AV1 features that was supposed to save bits versus H.264 and HEVC was its film grain modeling. But that only works for moderate degrees of grain. With the really heavy So, YouTube is pretty much the ideal AV1 platform for the moment, as it targets lower quality SW decode without DRM. It's utility for premium content is a lot lower for the moment due to lack of HW DRM, broader availability of HEVC, and high quality bar. Obviously trends are going in the right direction, as all the major CPU companies have announced AV1 HW decode support and AV1 quality-at-perf-at-bitrate has improved enormously in the last 12 months. But we're still several years away from having even 50% of PCs having HW AV1 support. A ROI justification for AV1 would be very hard to make right now. I imagine YouTube is spending far more to encode and store AV1 than they are saving in bandwidth at this point; it's not like they can stop encoding and storing the H.264 streams anytime soon. |
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19th October 2020, 18:51 | #2302 | Link |
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I've not investigated it myself yet, but I did see someone complaining recently that new Youtube videos were VP9 and AV1 only, not H.264
Dont know if that's related to Apple rolling out VP9. Or if its possibly just a change in which one gets encoded first. But we must be pretty close to Youtube not having to bother with H.264 anymore. They claim to no longer support IE11 and push people towards chrome. The fraction of people who can't view VP9 must be pretty small and shrinking. |
19th October 2020, 19:49 | #2303 | Link | |
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Netflix provides 4K at very low bitrates using new techniques like shot based encodings which are the worst thing I have ever seen on my 4K TV despite what they say here: https://netflixtechblog.com/optimize...g-47b516b10bbb I mean YouTube is many times better in encoding quality than these new "optimized" techniques. It's a nightmare and a legacy of Spring-Summer COVID bandwidth restrictions that they decided to fight using these failed new encodings in order to keep bandwidth low, especially in 4K content. As you work in the industry, is it possible to shake briefly their heads in order to open their eyes and see the mess they have caused ? I wonder when this nightmare of limited bandwidth will be over, hopefully before the unlimited COVID lockdowns.
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20th October 2020, 18:37 | #2304 | Link | ||||
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The current codec wars are a challenge, as many aren't adopting HEVC (which is broadly available outside of Chrome/Firefox) in favor of using H.264 now and hoping for AV1. HEVC can lower bandwidth by around 40% versus H.264 at similar quality with today's encoders. HEVC would be the best way to drop aggregate bandwidth/increase top bitrate quality in 2020-2021 while people wait for HW AV1 decoders to become common. |
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20th October 2020, 18:40 | #2305 | Link |
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I note that the RDNA 2 GPU that the Xbox Series S/X and the PlayStation 5 have customized versions of include AV1 HW decoders. Those might be the first high-volume AV1 HW decoder devices to the market. Game consoles get used a lot for premium content streaming.
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20th October 2020, 19:40 | #2306 | Link | |
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So, Netflix is already on the boat of HEVC 10bit since the beginning of 4K in 2014. The artifacts I'm talking about have nothing to do with low bandwidth or codec of 4K content, but with the change in encoding type as Netflix mentioned in its article. As I said before, the problem is not low bandwidth by itself but the way Netflix is trying to handle it using the "optimized" techniques of 4K re-encoding during the last few months.
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21st October 2020, 04:25 | #2309 | Link | |
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Unfortunately, I don't recognize many of the names on doom9 from the AV1 process, but please speak up if I'm mistaken. |
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21st October 2020, 19:19 | #2310 | Link | |
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I suppose it's possible one or both cut AV1 as a cost savings measure, but I can't imagine it's a material addition to a GPU of that complexity. It's more in the mobile SoC space where transistors and power are a such a high premium that adding AV1 could be a material cost hit. I guess I better get on a preorder for both and try them out. |
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21st October 2020, 19:27 | #2311 | Link | |
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Cross-pollination between the communities is always a really good idea. Any decent encoder development needs a lot of experienced eyes for subjective quality evaluation and tuning. There's been a historical bias towards objective metric tuning in the VPx and then AV1 development (PSNR first, now VMAF) which misses lots of psychovisual tuning opportunities. And VMAF is just not a sufficiently sensitive instrument to compare different adaptive quantization approaches. That's more an issue with the training set used for VMAF's machine learning, which was limited to x264 without much variation in AQ modes or strengths. Especially because AV1 itself and libaom were both tuned using VMAF, we'd really need a new set of subjective ratings of real-world AV1 encodes using a variety of different psychovisual tunings. That ground truth data would then make for a much better-trained VMAF for AV1 evaluation. As it is, the VMAF tuning baked in during AV1 and libaom development results in AV1 yielding VMAF scores that overestimate its subjective quality ratings versus, say x265 HEVC. That bias will go away if VMAF is retrained on subjective ratings of actual AV1 output. |
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22nd October 2020, 20:01 | #2313 | Link | |
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(DG2 = Xe-HPG/high-power Gen12 discrete; DG1 = Xe-LP/low-power Gen12 discrete) |
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23rd October 2020, 08:35 | #2314 | Link | |
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24th October 2020, 08:45 | #2315 | Link |
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Paint.NET now has full read/write .avif capability: https://blog.getpaint.net/2020/10/23...now-available/
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25th October 2020, 11:38 | #2316 | Link |
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For the owners of Ampere cards (haha it was a joke) there is a new version of NVEnc excellent transcoder by rigaya (the developer) who added AV1 HW decode in his app.
Obviously, you can't use the app for playback but only to transcode in HW even an AV1 clip. Give it a try, you two unique owners of Ampere cards: https://github.com/rigaya/NVEnc/issues/273
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29th October 2020, 17:42 | #2317 | Link |
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AMD's RX6000 gpu's can decode AV1, presumably fully hardware decode rather than hybrid decode: https://www.amd.com/en/products/grap...eon-rx-6800-xt
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29th October 2020, 18:46 | #2318 | Link |
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Very exciting to see 4kp60 4:2:0 10 bit AV1 hardware encoding in the next gen Intel 11th Gen!
https://www.anandtech.com/show/16205...th-xe-graphics I wonder if their encoder implementation is any good |
30th October 2020, 01:00 | #2319 | Link | |
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https://www.reddit.com/r/intel/comme...h_gen/gahs822/ Decoders: 1x 4k60 8b 4:2:0 AVC 4K60 12b 4:2:2/4:4:4 HEVC/VP9/SCC 4K60 10b 4:2:0 AV1 Encoders 4K60 8b 4:2:0 AVC 4K60 10b 4:4:4 HEVC/SCC/VP9, RA |
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30th October 2020, 01:57 | #2320 | Link |
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My understanding is that none of the new gen GPUs have HW AV1 encoding. Given its complexity, it may be pretty hard to get meaningful compression efficiency gains out of the mm^2 a GPU vendor is willing to devote to encode. The quality@perf math can be very different for a GPU.
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