• SLR

  • h265/HEVC v AV1 masters fight

phiber You're right, researching more into this, and it seems the resolution to aspect ratio is the issue here.

As you said, to be native 16K resolution without any cropping or upscaling and suitable for the standard side by side equirectangular 180° VR Video, we need 2:1 aspect ratio which is not achievable currently according to the AV1 latest 6.3 level. Hopefully they will address this in the next/ future levels.

As for the AV1 Tile width, I was talking from encoding standpoint of how we can achieve AV1 16K in the most reliable and fastest way with software encoders like SVT-AV1.

Because, currently, as of writing this, the most reliable and fastest way to encode and decode AV1 16K video is by using parallelism, mostly because of the current software encoders and hardware decoders limitations.

Since the Stereoscopic video sides are logically separate, we could also encode/ decode them separately. And AV1 pretty much supports this and here were the AV1 Tiles comes to play when encoding 16K resolution. This way it can be "fast" to encode and "light" to decode thus smooth to playback.

Because AV1 tiles are not fixed, but "flexible" which means they can be encoded in uniform and non-uniform tile spacing, and can be grouped into tile groups and each group can be encoded/ decoded independently.

This is the reason why RTX 5080/ 5090 have 2 Decoders, mostly to deal with "Multiview Videos" in very high resolutions like MV-HEVC for example:

https://blogs.nvidia.com/blog/generative-ai-studio-ces-geforce-rtx-50-series/

Although AV1 does not mention the same approach officially, but it actually can be done through SVT-AV1 and FFmpeg according to some 16K AV1 encoders as I read.

Personally, I can't confirm any of this, as I never encoded videos higher than 8192x4096 @60FPS @10-bit @400Mbps CBR for both AV1 and HEVC. Because that's the maximum of what my PC can encode easily and my RTX 4080 GPU can decode and play smoothly.

The VR 16K resolution videos are pretty much still undiscovered territory and most of us couldn't explored yet. When it comes to any VR video resolution higher than 8K, I'm still learning myself.

Now, that we'll finally have 16K VR Cameras like "Blackmagic URSA Cine Immersive" which also uses dual 8K sensors to achieve this ironically.

This will trigger everyone in various industries to invest, develop and advance the VR 16K @60FPS encoding and decoding and in both software and hardware for sure. Which will make the encoding/ decoding process less complex for the user and less taxing on the hardware.

Best Regards.

    AVP and recently the RTX 5000 line added hardware support for MV-HEVC. A format basically MADE for VR. My guess is that that's the future not AV1. Might take some time before enough devices support it though so I get why we have AV1 at the moment. But I think it would have been a more interesting development if they added MV-HEVC instead (even though I can't even play it yet). Bet the next quest, etc. will support this too.

    'MV-HEVC is an extension of the High Efficiency Video Coding (HEVC) standard, designed to efficiently compress multiple video views of the same scene captured from different vantage points. It addresses the limitations of traditional video-coding methods such as simulcast encoding, which often resulted in high bitrates for multi-view content and lacked efficient inter-view prediction."

      fenderwq Absolutely right, this is why the flagship RTX 50 series (RTX 5080 and 5090) has 2 Decoders actually.

        Hairsational Not really necessarily believe the world is actually flat as it's commonly understood when you think of a "flat-earther" But I do 100% believe that we have not been told the entire truth about the space program and what is actually out there, nor am I 100% certain we have even been to the moon, meaning actual humans and not just probes or unmanned missions. I think there is some shady stuff happening we are not privy to that could drastically change the way we perceive everything if we knew about it . There are a lot of people like myself that typically get sucked into the flat earther segment simply because of that but dont actually believe the world is flat like a piece of paper. To me being a flat earther is similar to how the whole "conspiracy theorist" label first started off as a way for the CIA and FBI to discredit actual whistleblowers and distract people from things we now know very well as truths. It's more of a badge of rebellion to go against the conventional principals we are told and taught to signal we dont actually buy all your BS and know there is more to it, we just dont know exactly what it is yet, if that makes sense?

            fenderwq right, what corporation will want to rally behind an open source codec if there are no licensing monies to be made haha

                • VVRXVR

                  • Post #57
                  • Edited

                  metichemsi Interesting point and could be debatable, but many streaming services are actually switching to AV1 to avoid paying licensing fees, and because it's more efficient than HEVC.

                    metichemsi That's fair. Anyone who genuinely believes the earth is flat in 2025 though... 😑

                      Can you guys point me to where SLR officially said that they won’t be sharing the higher bitrate files anyone? I’ve turned the whole forum upside down and still found nothing about it.

                        Hairsational They specifically say "streaming", I don't think people ever disputed the idea that AV1 will have better picture quality than HEVC at the same (low) bitrate that SLR uses. It's just that the comparison is pointless, because while AV1 might look better relatively, it still looks bad in an absolute sense, and definitely worse than the HEVC master.

                            phiber I mean which of the 6 scenes in the first post, because the AV1 and HEVC streaming versions have different bitrates.

                              HEVC seemed to me to be very slightly better in streaming than AV1 but for me, and in all codecs, the bitrate used is really too low for a site like SLR. I don't understand their goal of offering such low bitrates because it is the basis of their business. They can do the best video editing and tune their compression, a low bitrate will smooth out all the details. Maybe the majority of their customers are happy with the low bitrate but it is always better to satisfy advanced users to progress. Because one day these users will see the differences on other competing sites and will demand an increase in quality. And there are a lot of competing sites that offer bitrates above 50 mb/s. So if they want to save on licensing costs by using AV1, I have nothing against it, but the quality has to be there.

                                Hairsational well I was looking at the slr her scene with Nathan, I started comparing, going back in forth between the two versions...but this why i think av1 better, so as I was testing out both I thought well they kinda the same, both skip at the same rate while streaming, so going back in forth for a Lil while, thinking yeah I could see av1 looks slightly better, but here's where I made my choice..
                                Then I decided to change the file size version and bro the hevc version was at the highest version 4000 or something then I was going switch the av1, bro the whole time the av1 was on the second highest file, I was comparing two different file size but both looked the same, so I decided av1 looks better, for that particular video but I haven't tested the other examples.

                                  25 days later

                                  I downloaded two of them in the different versions to have a look and test them.

                                  The hevc encodes are often pretty good on this site. Not great, but passable. The same goes for the two videos I downloaded. The AV1 encodes here are worse. (Not to mention the horribly noise-reduced awful glowing encodes on recent AV1 releases from SLR Originals, but I digress.)

                                  Generally, AV1 tries to remove all skin detail, which it sees as noise, and since porn is all about skin you have to work around that. That is not being done here.

                                  First of all, don't encode on a GPU. It will be faster, but the result will be poor unless the bitrate is ridiculously high.
                                  Rather, encode on the CPU. Use SVT-AV1-PSY 3.0.2, or whatever is newest. It comes with Staxrip. You can just replace the codec build in the encoders folder if you want to use another build.
                                  Do not tune for SSIM or PSNR, they do not preserve skin detail. Outlines matter most for those. Tune for VQ.
                                  Do not use quantisation [quantization] matrices. They will blur skin and only save a small bit of size.
                                  You need to test-encode to see which bitrate (crf) is appropriate.
                                  Change the bit depth to 10 bits [ConvertBits(10) in AviSynth], before encoding. The codecs are most efficient when using 10 bits. (It's not the same as HDR, because it doesn't change the colorspace, and all players that I know of play it fine.)

                                  For the video: For Women: Royal Treatment
                                  The hevc version is okayish, but the av1 version looks really bad.
                                  Using the following non-default parameters to re-encode the large "original file" with SVT-AV1-PSY 3.0.2 I get a picture quality that is much better (a LOT better than the av1) than either of the two and a smaller file size:
                                  --rc 0 --crf 33 --preset 6 --tune 0 --tf-strength 3 --enable-qm 0 --sharpness 2 --enable-overlays 1 --qp-scale-compress-strength 2 --psy-rd 3 --hbd-mds 1

                                  For: Pink Me
                                  She's a bit of a porcelain doll, and the background is monotone so the video compresses well with any codec.
                                  Both the hevc and the av1 blur the skin however.
                                  You get better detail and the same file size with the "original" recoded with:
                                  --rc 0 --crf 23 --preset 6 --tune 0 --tf-strength 3 --enable-qm 0 --sharpness 2 --enable-overlays 1 --qp-scale-compress-strength 2 --psy-rd 3 --hbd-mds 1

                                  These encode at about 7 fps on a modern CPU, depending on what you have. Skip the two last parameters to speed it up a few fps, but it affects the quality slightly for the worse. By all means use preset 4 or even 2 if you have aeons or a supercomputer at your disposal. You might get a slightly smaller file size.

                                  Again: Do not encode on a GPU.

                                    sEARCHERNo00 I wish I understood what you were saying. I'm all about making the videos look better. I know the camera side, not really the computer side. If you'd care to help, feel free to send a direct message and I'll try some stuff.

                                      sEARCHERNo00
                                      Really hoping SLR staff takes notice of your explanations and testing. Working with tweaked encoding settings (especially adapted to the type of content to be encoded) could be beneficial both in terms of video quality and file sizes.
                                      @doublevr