CBR & VBR are confusing me...

[FusionMafia]

I'm converting al the Survivor episodes i've taped and want to burn them to DVDs. I've found out that at TMPGenc OK settings are CBR 4000kbs which lets me have 3 x 45min episodes on one DVD-R.

I tried to encode with VBR and 5000kbs as maximum 4000 as avarage and 3000 as minimum and can't see any difference between the earlier CBR encoded episode. Even the file sizes are same.

Do you have any tips about that? I would like to get rid of the blockiness in high motion scenes without making the file size bigger.

[Kooz]

jesus they some big bitrates! you should have NO blockiness!

CBR - Constant bit rate. the bitrate is forced for all frames, regardless of information in the frame. thus, a high action scene will have bitrate of XXXX and a black screen will have the same bitrate.

VBR - Variable bit rate. bitrate is varied according to information in the scene. thus, a high action scene will have XXXX bitrate and a black screen may have XX bitrate.

thats how i understand it. VBR should produce smaller file sizes.

I think you need to tell us your encoding process. I get DVD quality at about 12Mb per minute, less depending on source.

[Khizhiy]

It's simple. Using VBR you intend to lower the bitrate by giving the maximum bitrate to the high action scenes and squising simple ones into smaller places. It is the average bitrate value that you are supposed to lower. If you keep CBR and average VBR equal, you will still get better result for the VBR. Maybe, it is hard to distinguish without practice when the values are 4000 and higher.

[FusionMafia]

I fully understand the difference between VBR and CBR but i can't see any results in high motion scenes when I'm using VBR. And because the file size is exactly the same as using CBR makes me wonder if it's wise to waste time using VBR encoding.

[stanwebber]

your vbr bitrate range is needlessly narrow. specify 0 min, 9.8mbps max & let the encoder sort out the optimal bitrate allocation. dont worry, with an avg of 4000 the bitrate will never get anywhere close to 0 or 9.8mbps