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 > MPEG-4 ASP

Reply
 
Thread Tools Search this Thread Display Modes
Old 23rd September 2002, 17:52   #1  |  Link
pandv
Registered User
 
Join Date: Oct 2001
Posts: 62
Idea about saving space for 1 cd encodes (B-Frames and lumimasking like)

Sorry, I try to explain a complex thing in english, and I need to be very schematic to avoid confusion (if you want a spanish post, let me know).

The savings using B-Frames are in the quantizer increment, because the next frame is not affected (it's based in the previous P or I Frame).

In a normal encode we have K-blocks and M-blocks, the M-blocks are based in the previous one (from the previous frame), the K-blocks are independent.

So, if a block (M or K) in one position is followed by a K block in the next frame (same position), maybe we can increment the quantizer for this bloc, without visual notice (the bad quality is replaced in the next frame with a new block).

With MVHints, I think we have the needed information to compute this situation.

It's possible? It's realistic?

pandv.
pandv is offline   Reply With Quote
Old 23rd September 2002, 17:57   #2  |  Link
Koepi
Moderator
 
Koepi's Avatar
 
Join Date: Oct 2001
Location: Germany
Posts: 4,455
You got the idea right

But I really dislike the "abuse" of pframes for this matter as bframes are on their way and already looking very nice according to... uhm... I think it was sysKin

He has a better idea for MVhints: making them real hints as offset for improved motion search, resulting in an even better quality for 2pass+MVhints instead like now decreasing quality!

His motion estimation will become default soon and thus some other benefits, too.

Regards,
Koepi
Koepi is offline   Reply With Quote
Old 23rd September 2002, 18:28   #3  |  Link
-h
Kilted Yaksman
 
-h's Avatar
 
Join Date: Oct 2001
Location: South Carolina
Posts: 1,303
This is a good idea, but would probably be integrated with motion masking.

In that case, we would adaptively set the TOOSMALL_LIMIT value, which determines how sparsely detailed a block has to be before being skipped. We would increase the limit (skip more blocks) if the block happens to have a large motion vector, or additionally if we know that the next frame will replace that block with an intra block.

However that doesn't really happen all that often in the context of a full movie, but you may gain 1% or so in compression.

-h
-h is offline   Reply With Quote
Old 24th September 2002, 04:19   #4  |  Link
Aktan
Registered User
 
Join Date: Feb 2002
Posts: 258
"Every little bit helps"
Aktan is offline   Reply With Quote
Old 24th September 2002, 11:12   #5  |  Link
Koepi
Moderator
 
Koepi's Avatar
 
Join Date: Oct 2001
Location: Germany
Posts: 4,455
Integrating this with adaptive quantization is a great idea because you're willing to sacrifice some "original" blocks for bitrate there - this makes perfectly sense, I didn't think about that before, sorry.

But without lumi masking the resulting frames/macroblocks should be as close to the original as possible IMO.

Regards,
Koepi
Koepi is offline   Reply With Quote
Old 24th September 2002, 13:30   #6  |  Link
pandv
Registered User
 
Join Date: Oct 2001
Posts: 62
Happy to read good news about B-Frames and MVHints.

And, about skipping blocks, I proposed this only for 1 CD encodes, because the Koepi's statment (should be as close to the original as possible) it's true if you have enough bitrate available. If you are bitrate limited I am more for "should look as good as possible". So, if implemented, I think it need to be optional.

pandv
pandv is offline   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 12:46.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2017, vBulletin Solutions Inc.