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 > VP9 and AV1

Reply
 
Thread Tools Search this Thread Display Modes
Old 26th September 2022, 09:42   #1  |  Link
spoRv
Registered User
 
Join Date: Nov 2016
Posts: 151
AV1: MOD2 or MOD8 - which is better?

I'd like to convert some DCP 2K trailers; as they are 2048x858 and 1998x1080, hence MOD2, I'd like to know if, padding video with black borders until I obtain MOD8 (2048x864 and 2000x1080), AV1 will encode better or if it's the same.

AFAIR there were problems with MOD2 AVC and HEVC encoding with some hardware players; it's still the case with AV1?
spoRv is offline   Reply With Quote
Old 26th September 2022, 21:17   #2  |  Link
benwaggoner
Moderator
 
Join Date: Jan 2006
Location: Portland, OR
Posts: 4,752
Quote:
Originally Posted by spoRv View Post
I'd like to convert some DCP 2K trailers; as they are 2048x858 and 1998x1080, hence MOD2, I'd like to know if, padding video with black borders until I obtain MOD8 (2048x864 and 2000x1080), AV1 will encode better or if it's the same.

AFAIR there were problems with MOD2 AVC and HEVC encoding with some hardware players; it's still the case with AV1?
Mod compatibility issues are almost entirely due to decoder/video rendering problems, not encoding problems. In general, I'm 100% confident in Mod8, and secure with Mod4 as long as I can test across older players. The good news about using AV1 is that there isn't old AV1 hardware, so in theory everything should work, and any issues could be addressed with a firmware fix.
__________________
Ben Waggoner
Principal Video Specialist, Amazon Prime Video

My Compression Book
benwaggoner is offline   Reply With Quote
Old 5th October 2022, 17:07   #3  |  Link
spoRv
Registered User
 
Join Date: Nov 2016
Posts: 151
Quote:
Originally Posted by benwaggoner View Post
Mod compatibility issues are almost entirely due to decoder/video rendering problems, not encoding problems.
My fault... I wrote encoding when I meant decoding...

I try to use MOD8 at least - and MOD16 whenever possible.

Back to DCP resolution: I'm aware that 1998x1080 is perfectly 1.85:1, but isn't it "better" (easier? faster? better quality?), for resizers, to have for example 2000x1080 that, when multiplied x0.96 is 1920x1036.8 instead of 1998x1080 that should use x0.96096096... to get 1920x1037.8378368... ?
spoRv is offline   Reply With Quote
Old 6th October 2022, 11:12   #4  |  Link
StainlessS
HeartlessS Usurer
 
StainlessS's Avatar
 
Join Date: Dec 2009
Location: Over the rainbow
Posts: 10,980
JFYI, BlueRay h264 rip to MKV of 1920x1080 shows in DGIndexNV log window as being 1920x1088 internally.
(shows internal and external dimensions, Might depend upon encoder).
__________________
I sometimes post sober.
StainlessS@MediaFire ::: AND/OR ::: StainlessS@SendSpace

"Some infinities are bigger than other infinities", but how many of them are infinitely bigger ???

Last edited by StainlessS; 6th October 2022 at 11:15.
StainlessS is offline   Reply With Quote
Old 6th October 2022, 18:50   #5  |  Link
spoRv
Registered User
 
Join Date: Nov 2016
Posts: 151
I was aware of the 1920x1088 "thing" - I guess it was to maintain MOD16; I remember that some HDTV recording were indeed 1920x1088, and IIRC few were 1280x1088!
Indeed MOD16 was used for SD resolution on DVD, VCD, SVCD, DVB: 720x576, 704x576, 720x480, 704x480, 544x576, 544x480, 480x480, 352x288, 352x240
spoRv is offline   Reply With Quote
Old 7th October 2022, 10:09   #6  |  Link
nevcairiel
Registered Developer
 
Join Date: Mar 2010
Location: Hamburg/Germany
Posts: 10,344
Internally h264 is always mod16, and more modern codecs even use bigger blocks and av1 can use up to 128x128 superblocks resulting in a theoretical maximum of mod128, but in reality the encoder is likely going to use smaller blocks at the borders. All of these are technical details and irrelevant to the user, as the video is properly cropped automatically by the decoder to ignore the excess needed solely for encoding.
__________________
LAV Filters - open source ffmpeg based media splitter and decoders
nevcairiel is online now   Reply With Quote
Reply

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 01:14.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.