cbr vs vbr

[coops75]

If someone could give me a short answer I would appreciate it. I have a basic understanding of the difference, but with a 44 min project am I better off encoding at a cbr of say 8800 or 2-3 pass vbr with a low of say 4000, average of 7000 and max of 8800? This would be for a dvd project.
Would the picture quality be better using one over the other? Thanks again.

[Mirror_Image]

This isn't a short answer, but some a greater understanding of the diference between cbr and vbr might help:

http://tangentsoft.net/video/mpeg/enc-modes.html

In much greater detail:

http://www.research.ibm.com/journal/rd/434/westerink.html

Read or disregard as you see fit.

[energy80s]

For any bitrate, CBR will always give better quality than VBR as you are constantly throwing the maximum bitrate at every single MPEG frame. However if you are constrained by file sizes (ie. for fitting so much video on a single disc) then VBR is the way to go.

[Akai Rounin]

"...with a 44 min project am I better off encoding at a cbr of say 8800 or 2-3 pass vbr with a low of say 4000, average of 7000 and max of 8800?"

With encoding settings that high, the result is likely to be awesome for a 44 minute file either way. My preference is to always use a Constant Bit Rate (CBR). What really matters is if the maximum encode level can be read on your playback device, standalone DVD or VCD player.

What is your source? Is it really so high a quality as to require so high an encode rate? Are you just trying to archive or preserve as much of the video data as possible for the future?

HUN-YA!

Akai Rounin

[mh2360]

I always find that CQ (constant quality) set to about 70 - 80, max bit-rate to 2500, min bit-rate to 1150, lets me fit about an hour of good quality SVCD onto a 80 Min CDR... depends on movie though, lots of action means bigger file. This encodes MUCH faster than VBR...

[SLK001]

For only 44 minutes (and if you don't want to put anything else on your DVD), using CBR will encode faster than VBR (but you will use up most of your disk). Perceptual quality differences between the two encoding methods mentioned would be virtually nil.

In this case, I would go for the high bps CBR, author, and then just burn to DVD... Short, quick and relatively easy.

[coops75]

Thanks for the info. Akai- the source is dv and the final mpeg2 using cbr does look good. I used a high bitrate because I am new at this and just figured what the heck? But I will try again at a lower bitrate and see if I can notice much of a difference/ Say 6000. I encode directly from the Premiere timeline and that looks a lot better than rendering the avi and then dragging it into cce.
I understand that the max bitrate to use is about 9600 but many dvd players have difficulty reading that high a br. Perhaps that is why discs play well at my house but will not play on my parents machine even though it is supposed to play dvd-r. Thanks again