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 AVC / H.264

Reply
 
Thread Tools Search this Thread Display Modes
Old 23rd December 2013, 21:29   #1  |  Link
Nico8583
Registered User
 
Join Date: Jan 2010
Location: France
Posts: 796
Quality of BD50 to BD25 then BD25 to CRF ?

Hi,
I have made about 220 movies backups with BD Rebuilder from BD50 to BD25 (profil slower, 1 audio track and movie only) but now I would like to convert them to MKV CRF (between 20 and 23).
I would like to know if there is a big quality difference if I use BD25 source instead of BD50 ? I have all BD25 on my NAS so I don't need to rip original if I can use BD25.
Thanks for your advises !
Nico8583 is offline   Reply With Quote
Old 23rd December 2013, 23:33   #2  |  Link
LoRd_MuldeR
Software Developer
 
LoRd_MuldeR's Avatar
 
Join Date: Jun 2005
Location: Last House on Slunk Street
Posts: 13,208
Why not simply remux your existing BD25 rips to MKV without re-encoding at all?
__________________
There was of course no way of knowing whether you were being watched at any given moment.
How often, or on what system, the Thought Police plugged in on any individual wire was guesswork.


LoRd_MuldeR is offline   Reply With Quote
Old 24th December 2013, 00:15   #3  |  Link
Rumbah
Registered User
 
Join Date: Mar 2003
Posts: 473
Well, in my experience you get much smaller files than 25GB for a movie even with crf 20.

I always use crf 20 preset veryslow level 4.1 and get about 5-10GB per movie file, subtitles and audio included.
__________________
x264 full help - x264 --fullhelp r2345
Cuttermaran HCEnc provider - Support for HCEnc in Cuttermaran
DualDVDRB - Dual core support for DVD-RB free
Rumbah is offline   Reply With Quote
Old 24th December 2013, 00:22   #4  |  Link
Nico8583
Registered User
 
Join Date: Jan 2010
Location: France
Posts: 796
@LoRd_MuldeR : Because I would like to reduce file size to store files on a little NAS

@Rumbah : Interesting point, do you see any difference between BD50 and CRF20 ? You keep 1080p or you resize to 720p ? And I suppose you don't keep HD audio ?

But I'm afraid to see a big difference between BD50 -> MKV and BD25 -> MKV :/
Nico8583 is offline   Reply With Quote
Old 24th December 2013, 00:28   #5  |  Link
Sharc
Registered User
 
Join Date: May 2006
Posts: 3,828
I would assume that the bigger quality loss comes from encoding with CRF 20....23 which will mask the difference between the original BD50 or the BD25 backup as source for the re-encoding.
Sharc is offline   Reply With Quote
Old 24th December 2013, 01:13   #6  |  Link
benwaggoner
Moderator
 
Join Date: Jan 2006
Location: Portland, OR
Posts: 3,751
You could also make your BD-25 discs with CRF 20 in the first place.
__________________
Ben Waggoner
Principal Video Specialist, Amazon Prime Video

My Compression Book
benwaggoner is offline   Reply With Quote
Old 24th December 2013, 02:49   #7  |  Link
Nico8583
Registered User
 
Join Date: Jan 2010
Location: France
Posts: 796
@sharc : it would be great ;-)
@benwaggoner : if CRF20 looks good for me, perhaps I'll stop to make BD25. But first thing is to know quality loss from BD25 :-/
Nico8583 is offline   Reply With Quote
Old 24th December 2013, 13:26   #8  |  Link
LoRd_MuldeR
Software Developer
 
LoRd_MuldeR's Avatar
 
Join Date: Jun 2005
Location: Last House on Slunk Street
Posts: 13,208
Quote:
Originally Posted by Nico8583 View Post
if CRF20 looks good for me, perhaps I'll stop to make BD25. But first thing is to know quality loss from BD25 :-/
I'd agree with Sharc: If the CRF=20 encode comes out at about half the average bitrate (file size) of the BD25 encode, then you probably won't notice the difference between the BD25 and the BD50 source.

But only with some testing you will know for sure
__________________
There was of course no way of knowing whether you were being watched at any given moment.
How often, or on what system, the Thought Police plugged in on any individual wire was guesswork.



Last edited by LoRd_MuldeR; 24th December 2013 at 13:39.
LoRd_MuldeR is offline   Reply With Quote
Old 24th December 2013, 17:29   #9  |  Link
Rumbah
Registered User
 
Join Date: Mar 2003
Posts: 473
I don't see any difference between the BD50 and the CRF20 encode on my TV. That's why I keep it that way.

I always use 1080p. I think you wouldn't see any difference between a BD25 to CRF20 as with most BD50 releases the movie itself isn't bigger than 25GB. But the only way to judge the quality is to just test it with your eyes.

For the audio part I use 448 ac3 5.1 as my Pi can play it without a problem and it sounds good to me. And most amplifiers take the direct spdif stream.
__________________
x264 full help - x264 --fullhelp r2345
Cuttermaran HCEnc provider - Support for HCEnc in Cuttermaran
DualDVDRB - Dual core support for DVD-RB free
Rumbah is offline   Reply With Quote
Old 24th December 2013, 19:27   #10  |  Link
Video Dude
Senior Member
 
Join Date: Apr 2004
Posts: 1,049
Quote:
Originally Posted by Nico8583 View Post
Hi,
I have made about 220 movies backups with BD Rebuilder from BD50 to BD25 (profil slower, 1 audio track and movie only) but now I would like to convert them to MKV CRF (between 20 and 23).
I would like to know if there is a big quality difference if I use BD25 source instead of BD50 ? I have all BD25 on my NAS so I don't need to rip original if I can use BD25.
Thanks for your advises !
Since you did movie only with only one audio track, there is a good possibility that not all movies were recompressed in BD-RB as they could already fit on the BD-25. It is the menus, extras, and additional audio tracks that push it over to BD-50 many times.

Before re-ripping your collection, take a look at the file sizes and look for discs smaller than typical BD-RB x264 compressed target size. This would indicate BD-RB only remuxed the video and the video stream would match 1:1 with the source. This will save you time and effort of re-ripping those discs.
Video Dude is offline   Reply With Quote
Old 24th December 2013, 21:43   #11  |  Link
benwaggoner
Moderator
 
Join Date: Jan 2006
Location: Portland, OR
Posts: 3,751
Note you can make BD-25 compatible bitstreams WITH CRF. The -vbv-bufsize etcetera will still apply and keep things compliant.

For BD-25 and CRF 20, I'd recommend going down to a 25 Mbps peak and Level 4.0, which allows you to turn --slices 4 off. If you go down to a 15 Mbps peak, you can also use a 2 sec max GOP instead of 1 sec, and that might be just fine with CRF 20 and high-quality encoding settings.
__________________
Ben Waggoner
Principal Video Specialist, Amazon Prime Video

My Compression Book
benwaggoner is offline   Reply With Quote
Old 25th December 2013, 11:18   #12  |  Link
Nico8583
Registered User
 
Join Date: Jan 2010
Location: France
Posts: 796
Thanks to all for your responses, I'll make a try soon
But my goal is to stop to make BD25 because an optical disk is too much expensive versus a HDD :/
Nico8583 is offline   Reply With Quote
Old 27th December 2013, 01:36   #13  |  Link
foxyshadis
ангел смерти
 
foxyshadis's Avatar
 
Join Date: Nov 2004
Location: Lost
Posts: 9,564
Quote:
Originally Posted by benwaggoner View Post
Note you can make BD-25 compatible bitstreams WITH CRF. The -vbv-bufsize etcetera will still apply and keep things compliant.

For BD-25 and CRF 20, I'd recommend going down to a 25 Mbps peak and Level 4.0, which allows you to turn --slices 4 off. If you go down to a 15 Mbps peak, you can also use a 2 sec max GOP instead of 1 sec, and that might be just fine with CRF 20 and high-quality encoding settings.
I had no idea you could have a larger GOP depending on the bitrate. Thanks, that's incredibly handy to know! (Of course, the PS3 doesn't care anyway.)
foxyshadis is offline   Reply With Quote
Old 29th December 2013, 23:26   #14  |  Link
benwaggoner
Moderator
 
Join Date: Jan 2006
Location: Portland, OR
Posts: 3,751
Quote:
Originally Posted by foxyshadis View Post
I had no idea you could have a larger GOP depending on the bitrate. Thanks, that's incredibly handy to know! (Of course, the PS3 doesn't care anyway.)
Yeah, it can be helpful when targeting lower average bitrates when you really weren't going to get peaks that high anyway.

Generally x264 does very nicely with 15 Mbps peaks for 1080p24 content.
__________________
Ben Waggoner
Principal Video Specialist, Amazon Prime Video

My Compression Book
benwaggoner is offline   Reply With Quote
Old 30th December 2013, 20:45   #15  |  Link
plonk420
amd & h.264 fanboy
 
plonk420's Avatar
 
Join Date: Jun 2002
Location: NTSC
Posts: 419
also, convert your lossless audio to 5.1 640kbps AC-3 (or, if you're okay with 448kbps, as previously mentioned)
plonk420 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 04:04.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2021, vBulletin Solutions Inc.