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1. Re: VBR or CBR for H.264 Blu-Ray?
JSS1138 Apr 13, 2013 9:23 AM (in response to EdwurdAdam) -
2. Re: VBR or CBR for H.264 Blu-Ray?
Rallymax-forum Apr 15, 2013 1:24 PM (in response to JSS1138)Jim Simon wrote:
Neither. CQ mode is best.
http://tangentsoft.net/video/mpeg/enc-modes.html
For more information on a description of Constant Qiuality (CQ) vs Constant or Variable Bitrate (CBR, VBR) have a look here on page 5..
http://www.x264pro.com/wp-content/uploads/x264_PRO_Help.pdf
The Adobe bundled h.264 doesn't have CQ though so it's best to go with VBR vs CBR because it will steal bits from less complex frames before and after when it's needed. It will also allow short term bursts of information (up to the Maximum threshold) so that when bits are needed it can use them. - eg a scene change.
Also, do 2-pass. The first pass it will learn about when it's going to easy and hard to make frames. With that information on the second pass it can steal from the future since it knows that the future frames might not need many bits.
Also, if you have a very simple frame it will reduce the bitrate and save you on the total size. If you use Constant Bitrate you don't have any of these efficiencies.
Constant Quality doesn't look at the problem from a bit perspective. It makes a variable bitrate based on the quality of each frame you want to hit.
'hope that helps.



