Sounds like a no brainer - VBR gives the extra data rate when its needed but does not waste it when its NOT needed. Whats not to like.

I was surprised several heavy-hitting-forum-ites recommending CBR?!?!?! Stability is the issues? Is this accross many DVD players or accross an entire 2-3 hr movie, or accross a wide range of data rates?

I have always used VBR having no trouble (so far) and not hearing anything on this forum in several years of as a member. Thats why I pose the question.

I have allways used VBR and it has allways worked good for me ..Accept with SVCD"s you can sometimes run into problems if you set the Minimum too low and the Max too high then sometimes you can get sudden Bitrate jumps that can cause the Picture to slow down then speed up again cuz the DVD Player cant speed the Disk up fast enough to read the sudden spike in the bitrate, but besides that it has been great and much better than CBR with File size and Quality...

I agree. VBR is better than CBR in most cases, especially when making a DVD that is longer than 1 hour, or making a SVCD longer than 40 minutes. If your average bitrate is close to the maximum bitrate of the medium then there is no need to use VBR because you don't need to save bits.

I have had some troubles with VBR SVCD's on my standalone player and this is of the reason lucifer said. It skips or freezes if the minimum bitrate is too low, the maximum too high or if the bitrate variation too big. This is one reason that I only use CBR when encoding SVCD with Canopus Procoder because the minimum bitrate in my "demo" is set too low to work in my player and it can't be adjusted in Procoder. But it works if I set a higher minimum bitrate in TMPGEnc or CCE.

Are you sure the recommendation is for the video part? I can understand if they recommend CBR audio because VBR audio is not supported by SVCD / DVD standards.


Ronny

First of all, CBR and VBR and part of the same beasty. After all, even CBR has necessary differences in bitrate here and there.

However, I've found CBR particularly useful in two circumstances:

1. When transcoding to another format. Sometimes I like to put things in VCD MPEG1, or I'll be moving Pal to NTSC. In those cases I'll usually encode at 8-10mbs CBR because there seems to be less chance for audio to get out of synch in the transcode process...or at the very least its a stable shift rather than a progressive one, which seems more likely with VBR.

2. I use CBR for MPEG2 SVCD with my Dazzle card when I'm using the apollo drivers because otherwise I get blocks at the lower bitrates.

cheers,
mark

I should think the VBR is MOST HELPFUL at lower rates and almost totally useless at high rates???

But this touches on my next post regarding the capture of noisy sources.... Perhaps a high CBR might be better than VBR at any rate...

Well check out my post on this. I hope it gets interesting...

High bitrate CBR will allways be better than any bitrate VBR.

VBR was invented for one purpose only - not to improve quality - but to get good quality in smaller filesize by lowering the bitrate when high bitrate is not really needed. But naturally a constant bitrate of 10mbs will be better overall than a VBR at max 10mbs that drops every now and then. The cost of CBR is space - an mpeg encoded in pure CBR takes up more space than an equal VBR mpeg.

The equation is dependent on available space - if you only have a certain amount of space for a specific playingtime - you might only be able to get a constant bitrate of 4mbs - then it may be possible to actually increase quality by using VBR that saves space by lowering the bitrate to say 2mbs in easy areas making it possible to use that extra space to increase the bitrate to 6mbs in more difficult areas and still end up with the same filesize.

But if you have enough space to use highbitrate 10mbs CBR and still make your project fit - then that will give you best quality.