Welcome to Doom9's Forum, THE in-place to be for everyone interested in DVD conversion. Before you start posting please read the forum rules. By posting to this forum you agree to abide by the rules. |
![]() |
#1401 | Link | |
Registered User
Join Date: Aug 2015
Posts: 34
|
Quote:
![]() Last edited by TD-Linux; 30th January 2019 at 01:45. |
|
![]() |
![]() |
![]() |
#1402 | Link |
Registered User
Join Date: Oct 2017
Posts: 56
|
I originally created the figure and presented it for the first time during Streaming Tech Sweden 2017. There have been some changes since then.
Here is an updated figure: ![]() Please note that the figure is only based on public information available from ISO/IEC/ITU and from the patent pools. Please also note that not all of the MPEG LA patent holders are shown in the figure. |
![]() |
![]() |
![]() |
#1403 | Link | |
Registered User
Join Date: Mar 2004
Posts: 1,011
|
Quote:
|
|
![]() |
![]() |
![]() |
#1404 | Link | |
VP Strategy, Beamr
Join Date: Jan 2018
Location: Palo Alto, CA
Posts: 50
|
Quote:
Even with the updates, the main problem with this chart is that it's a bit misleading.. for 2 reasons. First, I think most people in the video industry assume that AVC patent licensing is and was perfectly clean and simple... that all necessary standard-essential patents were licenseable in the MPEG LA patent pool. That's not true. Nokia, Qualcomm, Broadcomm, Blackberry, Texas Instruments, MIT all hold standard-essential AVC patents outside the MPEG LA pool (although Qualcomm messed up and a judge ruled they can't assert them for AVC). Multiple legal battles have been fought over AVC patents, including some pretty big cases... Microsoft v Motorola, and Apple v Nokia. Today, everyone can agree that the patent licensing situation for AVC is much better than it is for HEVC. But it didn't start out that way, and it took some time for the situation to settle. Also, there are quite a few more patent holders in some of these HEVC pools than shown in this chart. In his talk, Tim mentioned that patents are issued that may not be valid, and then said "and you could go around and try to invalidate them all, but they're really expensive to do that, and there's a lot of them". Well, if you're a multi-billion dollar company (Apple, Samsung, Google, Amazon, etc.), you have a lot of lawyers, and that's what they're paid to do. If you're being asked to pay tens or hundreds of millions of dollars a year in patent license fees, you have all the motivation in the world to spend whatever it takes on legal fees to right-size the problem. When multiple multi-billion dollar companies have this issue, collectively there is a lot of motivation. It turns out that when challenged in court, most patents don't hold up. They can be invalidated for many reasons... prior art, unpatentable claims, obviousness, the invention was anticipated, etc. This type of effort is being undertaken by Unified Patents (as a service to many large tech companies), and there is a relatively new law called the America Invents Act that provides a faster, less expensive way to get rid of bad patents, called an Inter Partes Review (IPR). Unified already filed an IPR against Velos Media, and you can expect more such filings under their Video Codec domain. But you don't even have to invalidate patents in order not to pay a fortune. Again, keep in mind that no one is asking for patent license fees for content distribution (streaming, etc.), except for UHD-Blu-ray disc (a small per-disc fee to HEVC advance). Only hardware device manufacturers need to license HEVC patents, and they are dealing with that issue and they continue to support HEVC in every device they make that supports video. For video services, HEVC is free. Now that the majority of active end-user devices support HEVC, it makes a lot of financial sense for video services to make their VOD catalog, or the majority of their live channels available in both AVC and HEVC (not just 4K and HDR content... all content). The bandwidth savings and customer experience improvement far outweigh the additional cost of encoding and CDN storage. |
|
![]() |
![]() |
![]() |
#1406 | Link | |
VP Strategy, Beamr
Join Date: Jan 2018
Location: Palo Alto, CA
Posts: 50
|
Quote:
|
|
![]() |
![]() |
![]() |
#1408 | Link | |
Registered User
Join Date: Oct 2014
Posts: 464
|
Quote:
|
|
![]() |
![]() |
![]() |
#1409 | Link | |
Registered Developer
Join Date: Mar 2010
Location: Hamburg/Germany
Posts: 10,044
|
Quote:
One encode, several metrics. Not re-encoding targeted for metrics.
__________________
LAV Filters - open source ffmpeg based media splitter and decoders |
|
![]() |
![]() |
![]() |
#1410 | Link | |
Registered User
Join Date: Aug 2015
Posts: 34
|
Quote:
https://beta.arewecompressedyet.com/...y-525f981376bd |
|
![]() |
![]() |
![]() |
#1411 | Link | |
Registered User
Join Date: Jun 2013
Posts: 89
|
Quote:
The real problem is that VMAF is not that good. It, for example, spectacularly fails with samples that greatly benefit from AQ (yes, I know you already hinted at this).
__________________
saldl: a command-line downloader optimized for speed and early preview. |
|
![]() |
![]() |
![]() |
#1412 | Link | ||
Registered User
Join Date: Oct 2017
Posts: 56
|
Quote:
Quote:
|
||
![]() |
![]() |
![]() |
#1413 | Link | |
Registered User
Join Date: Feb 2003
Location: New York, NY (USA)
Posts: 82
|
Quote:
Netflix uses "hVMAF" as official notation in their charts. "h" means "harmonic", which means it uses harmonic means, which bias towards the least favourable. So in your example, the harmonic mean would be 62.66, whereas the average would be 62.86. Neither of these is 65.3. So I'm personally not as concerned about the averaging mechanism aspect of your concern. (In the CLI, use --pool harmonic_mean or something similar, depending on which exact tool you use.) On the other hand, I don't believe that VMAF uses temporal consistency in the reconstruction (the "motion" component is calculated from the source), so that particular concern ("frame throbbing" - i.e. keyframe pulsing or grain/textured-background tearing) I agree with. [edit] Actually, I have to hedge a little here, since I'm not 100% sure VIF (another VMAF component) has a temporal component to it. I don't think it does but I'm not 100% sure. [/edit] Since we're on the subject, here's some more of my personal concerns about VMAF: * it's luma-only; * AQ (x264/5) or SAO (x265) appear to have a negative impact on vmaf score, which is inconsistent with the reported visual results. I do have more detailed thoughts on this but let's leave that for some other time; * the actual MOS/VMAF correlation depends very strongly on the viewing environment and therefore on the used model file, but most poeple simply use the default model without knowing what viewing environment it represents. Just to be clear, I'm not trying to talk badly about VMAF, I think it's a great tool, it's better than the alternatives and it's fantastic that they opensourced the library as well as the models so that we can learn and understand how it works and constructively critique it. Hopefully, over time, that will make it even better, which should be the ultimate goal. Separately, I also do agree with you that in the end, we should probably make a distinction between codecs optimized using VMAF vs. those that did not. This isn't an excuse to suck at writing encoders or to not use VMAF when writing encoders, but at the end of the day, we have to acknowledge that as in any metric, we're assuming a perfect correlation between our metric-of-the-day and the visual experience (or MOS score). That correlation will in practice always be imperfect, and therefore tuning towards/using that metric needs to be done with care and with visual confirmation (otherwise queue up the incoming VMAF artifacts - I wonder what they will look like?). Last edited by Beelzebubu; 30th January 2019 at 22:11. |
|
![]() |
![]() |
![]() |
#1414 | Link |
Registered User
Join Date: Jun 2013
Posts: 89
|
@Beelzebubu
What's really funny, Netflix will not be using VMAF on their published AOM content as is. Why? Because of film grain synthesis ![]()
__________________
saldl: a command-line downloader optimized for speed and early preview. |
![]() |
![]() |
![]() |
#1415 | Link | |
Moderator
![]() Join Date: Jan 2006
Location: Portland, OR
Posts: 3,536
|
Quote:
If VMAF is bad at dealing with film grain, they need to address that. The nice thing about VMAF is that it's really a machine learning framework. They can keep on adding new clips and kinds of encodings and training it to rate those. The big expenses is getting the subjective ratings to use as ground-truth data. But VMAF itself can always be as good as the ground truth data from subjective testing. |
|
![]() |
![]() |
![]() |
#1416 | Link | |
Registered User
Join Date: Aug 2015
Posts: 34
|
Quote:
I don't know what Netflix currently does, but if I were them I would filter the grain from the video, run the VMAF-targeting dynamic optimizer to produce the rate controlled stream, and then add the noise parameters back as a final step. |
|
![]() |
![]() |
![]() |
#1419 | Link | |
Moderator
![]() Join Date: Jan 2006
Location: Portland, OR
Posts: 3,536
|
Quote:
|
|
![]() |
![]() |
![]() |
#1420 | Link | ||
Member
Join Date: Nov 2002
Posts: 147
|
SVT-AV1 encoder!
https://github.com/OpenVisualCloud/SVT-AV1
Quote:
![]() Quote:
|
||
![]() |
![]() |
![]() |
Thread Tools | Search this Thread |
Display Modes | |
|
|