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.

 

Go Back   Doom9's Forum > Video Encoding > New and alternative video codecs

Reply
 
Thread Tools Search this Thread Display Modes
Old 18th May 2018, 14:09   #61  |  Link
pie
Registered User
 
pie's Avatar
 
Join Date: Sep 2012
Posts: 16
Quote:
Originally Posted by LigH View Post
Building the googletest sources fails
iirc with mingw you need to pass -Dgtest_disable_pthreads=ON or something to that effect.
pie is offline   Reply With Quote
Old 18th May 2018, 14:26   #62  |  Link
LigH
German doom9/Gleitz SuMo
 
LigH's Avatar
 
Join Date: Oct 2001
Location: Germany, rural Altmark
Posts: 5,309
@pie: That was the old "master" version.
_

@jonatans:

This dev version crashes reading from a Y4M:

Code:
Assertion failed!

Program: E:\Programme\xvc\Win64\xvcenc.exe
File: H:/development/media-autobuild_suite-master/build/xvc/app/xvc_enc_app/y4m_reader.cc, Line 124

Expression: pic_fmt.input_bitdepth != 0
Source is the usual "foreman" clip from Derf's collection on xiph.org, only patched to PAL frame rate:

Code:
YUV4MPEG2 W352 H288 F25:1 Ip A128:117
FRAME
Maybe a "C420" should be added to the Y4M header so that your Y4M reader knows exactly which YUV variant it is?
__________________

German Gleitz board
MediaFire: x264 | x265 | VPx | AOM | Xvid
LigH is offline   Reply With Quote
Old 18th May 2018, 14:47   #63  |  Link
jonatans
Registered User
 
Join Date: Oct 2017
Posts: 23
Yes, our y4m parser assumed that the C parameter would be present in the y4m header.

I have just changed so that "C420" is assumed if there is no C parameter present.

I also added support for "Cmono".
jonatans is offline   Reply With Quote
Old 18th May 2018, 17:45   #64  |  Link
LigH
German doom9/Gleitz SuMo
 
LigH's Avatar
 
Join Date: Oct 2001
Location: Germany, rural Altmark
Posts: 5,309
A good reason to build anew: xvc-dev 2018-05-18 bbf1325
__________________

German Gleitz board
MediaFire: x264 | x265 | VPx | AOM | Xvid
LigH is offline   Reply With Quote
Old 22nd May 2018, 19:59   #65  |  Link
benwaggoner
Moderator
 
Join Date: Jan 2006
Location: Portland, OR
Posts: 2,431
Quote:
Originally Posted by augman000 View Post
By the way: I am really liking xvc. It is beating AV1, x265, and VP9 in my tests with PSNR and SSIM scores. I'd like to measure VMAF as well but I have been unsuccessful in all my attempts to compile a working win64/win32 binary.
SSIM and especially PSNR are not very good metrics, particularly with advanced new codecs. Or anything that is psychovisually tuned.

VMAF is probably the least-bad objective metric we have, but still has some pretty big limitations and blind spots. It wasn't tested with anything >1080p or below something like 300 Kbps. SDR 8-bit only. A quite weak temporal comparison module. And it was trained on just x264, and so doesn't know what to do with new types of artifacts AV1 and HEVC can have.

Plus there's the whole question of how you aggragate individual frame scores into a clip score. Just the mean of the metrics can't discriminate between content that is consistently mediocre versus oscillating between terrible and pristine.

With a new codec, actually looking at it is really the only thing that can give a better than a rough ballpark. Certainly a difference of less than 5 VMAF, 4 PSDR dB, and 3 SSIM dB should be verified visually.
__________________
Ben Waggoner
Principal Video Specialist, Amazon Instant Video

My Compression Book

Amazon Instant Video is hiring! PM me if you're interested.
benwaggoner is offline   Reply With Quote
Old Yesterday, 05:13   #66  |  Link
maxcoolzero
Registered User
 
maxcoolzero's Avatar
 
Join Date: Apr 2018
Location: NY, USA
Posts: 3
Wow. Looks cool
maxcoolzero is offline   Reply With Quote
Old Yesterday, 09:12   #67  |  Link
jonatans
Registered User
 
Join Date: Oct 2017
Posts: 23
Quote:
Originally Posted by benwaggoner View Post
SSIM and especially PSNR are not very good metrics, particularly with advanced new codecs. Or anything that is psychovisually tuned.

VMAF is probably the least-bad objective metric we have, but still has some pretty big limitations and blind spots. It wasn't tested with anything >1080p or below something like 300 Kbps. SDR 8-bit only. A quite weak temporal comparison module. And it was trained on just x264, and so doesn't know what to do with new types of artifacts AV1 and HEVC can have.

Plus there's the whole question of how you aggragate individual frame scores into a clip score. Just the mean of the metrics can't discriminate between content that is consistently mediocre versus oscillating between terrible and pristine.

With a new codec, actually looking at it is really the only thing that can give a better than a rough ballpark. Certainly a difference of less than 5 VMAF, 4 PSDR dB, and 3 SSIM dB should be verified visually.
Thanks Ben, those are all very valid points.

I agree that PSNR is not a very good metric for determining visual quality. It is good for determining how close the compressed pictures are to the original pictures (in a mathematical sense - after all that is what PSNR measures, on a sample by sample basis). So if two different implementations are tuned to minimize MSE ("tune PSNR") then PSNR gives a good indication of how good the implementations are at doing just that. And even though this generally doesn't correlate well with visual quality it is good in the sense that it does not give any "false positives" (i.e. if one compressed picture A is tuned towards PSNR you cannot easily create another compressed picture B with higher PSNR by making it look worse than A).

We have put some results for the NETVC test conditions and test sequences at awcy.divideon.com, comparing xvc to AV1, both codecs with PSNR tuning (https://awcy.divideon.com/?job=1pass...3A34%3A38.388Z) including results for PSNR (16.5% savings) MS-SSIM (23.3% savings) and VMAF (18.5% savings). It can be seen that the gains are quite sequence dependent but the overall trend is very clear and quite consistent among the metrics.

There is also a comparison between xvc and HM (https://awcy.divideon.com/?job=1pass...3A34%3A38.388Z) which shows slightly larger bitrate savings.

But, as you correctly point out, what matters in the end is the visual quality which can only be determined by actually looking at compressed video (encoded under fair conditions when it comes to complexity etc.)

Please share your impressions if you have had a chance to look at any xvc encoded sequences or made any visual comparisons.
__________________
Jonatan Samuelsson
Co-founder and CEO at Divideon

www.divideon.com | xvc.io
jonatans is offline   Reply With Quote
Reply

Tags
codec, compression, video codec, video encoding, xvc

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +1. The time now is 05:06.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2018, vBulletin Solutions Inc.