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12th February 2015, 10:49 | #1 | Link |
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webm (vp9/opus) stuttering on mobile
Hi from Italy;
i'm making several tests with vp9. I want to understand if i can use vp9 istead of h.264 to improve quality/bitrate of my videos online. i have some problems. Firefox and Chrome (desktop windows) can playback without problems WebM(vp9/opus) videos. Chrome on Nexus 4 , Samsung Galaxy S3, Nexus7, with Kitkat or Lollipop, has stuttering problems. There is not a bandwith problem because videos are server by local web server. I tried with several encoders and several parameters (changing profile from 0 to 3) but nothing changes. so, with youtube-dl i downloaded some youtube videos, and those videos works well, but has no audio track (?). i tried to understand what are differences about my videos and youtube videos by mediainfo, but i'm not able to understand what change. this is a sample use of encvpx.exe script called by "Hybrid" encoder gui. Hybrid is the name of the software. vpxenc --codec=vp9 --passes=1 --pass=1 --target-bitrate=1500 --end-usage=vbr --good --cpu-used=3 --undershoot-pct=0 --buf-sz=6 --buf-initial-sz=4 --buf-optimal-sz=5 --drop-frame=0 --resize-allowed=0 --kf-min-dist=0 --kf-max-dist=250 --auto-alt-ref=0 --noise-sensitivity=0 --sharpness=0 --static-thresh=0 --tile-columns=2 --tile-rows=2 --threads=8 --width=1280 --height=720 --yv12 -o "C:\Juassikvp9.vp9" - i tried also with mediaCoder, but nothing changed. any suggestions to avoid stuttering problem? How youtube encode vp9 avoiding stuttering problems? thanks. |
14th February 2015, 23:44 | #3 | Link |
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Be aware that most GPUs and mobile devices don't have hardware decoding of VP9 yet, so it has to be done in software. Because modern PCs have much faster CPUs than mobile devices, a typical modern PC will be able to decode VP9 video just fine while a mobile device will likely choke and turn into a stutter fest (this can also happens on older and lower-end PCs as well).
When it comes to YouTube on mobile, I believe the YouTube app currently defaults to h.264 (I'm not 100% sure on this, so I'm going to check in a bit...) If you really want to get VP9 playing on mobile, you'll probably have to use a lower resolution like 480p or 360p. Last edited by Nintendo Maniac 64; 15th February 2015 at 00:06. |
18th February 2015, 14:52 | #4 | Link | |
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19th February 2015, 04:08 | #5 | Link | |
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Not a lot of videos on youtube have Opus streams, though. And I don't know if browsers support VP9/Vorbis. AAC was never a part of webm's supported container codecs AFAIK. Personally, I don't care about codec combinations as I don't use browsers for playback. And Matroska supports all combinations. |
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19th February 2015, 07:27 | #6 | Link |
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Dedicated media players are likely to have better optimized decoder performance compared to web browsers. Case in point, MPC-HC v1.7.8 uses much less CPU for decoding VP9 than any web browser.
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20th February 2015, 14:24 | #7 | Link |
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@MoSal thanks, now i have understand.
i did not give an important information : i work on website and i want to use vp9 to give higher quality at the same bitrate instead of h.264. My first target is android because android does not support apple streaming very good so i must to use progressive download. Youtube webm content works good on my nexus4. i will try to understand @xooyoozoo indications and so i can publish an example page, if you are interested. thanks to all, really. |
20th February 2015, 17:32 | #8 | Link |
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Have you actually confirmed that with vp9 you're getting better quality than with x264 (--preset veryslow, 1-pass crf with vbv)?
Otherwise you're loosing h/w support that every device has, waste server storage and greatly increase encoding time for no reason whatsoever. |
21st February 2015, 11:18 | #9 | Link | |
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no? |
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22nd February 2015, 22:51 | #10 | Link | |
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If someone does have such a demo, I'd love to see it. |
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23rd February 2015, 10:32 | #12 | Link | |
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Like Ben, I would be most interested to see some comparisons.
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5th March 2015, 17:41 | #13 | Link | |
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i don't want to compare it subjectively. Talking about slower conversion of x264 i tried to keep Constant Quality (CF 20) and try slower to faster conversion. Slower makes smallest file. thanks. So, i tried also with H.265, but i obtained same size of x264 ... Your advices is very good for me, thanks, but i don't want to go off topic about vp9 stuttering problems on mobile, if possible. |
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5th March 2015, 19:27 | #14 | Link | ||
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All the standard metrics that get cited are also single-frame only, which means they don't account for how images change between frames. Since that's a critical component of moving video, codecs heavily optimized for SSIM and PSNR will tend to introduce temporal artifacts. x264 and x265 are primarily optimized towards subjective quality. There is the internal metric of "rate factor," but it's not designed to provide objective comparisons between difference pieces of content or different settings, and isn't available in any other codecs. Quote:
I'd expect that the limitation of VP9 would be based on single-core performance. Reducing frame size is the easiest way to improve performance, followed by reducing bitrate, and lastly reducing frame rate. Since frame rate needs to be divided by an integer, it's a particularly painful way to reduce CPU load, and is very rarely worth it unless you're already below 320x240. There have been improvements in VP9 decoder performance, so making sure that a recent one is being used would also help. Although enforcing that for customers would be challenging. |
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5th March 2015, 22:26 | #15 | Link | |
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The weird thing, though, is that Google's (and therefore Chrome's, Opera's, Firefox's) VP9 decoder needs the encoder to operate in `frame-parallel` mode, which additionally worsens entropy coding because that also disables the backward context update tool. |
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mobile, stuttering, vp9 |
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