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Originally Posted by Mug Funky
CBR encodes will render bitrate scans less useful though... some would say inadmissible as evidence of quality.
remember that commecial DVDs use CBR when there's room. simply because:
a) it's 1-pass and maximum quality, so if there's room on the disc, do it  . |
I am not saying you are wrong, but your experience completely flies in the face of my experience.
First of all, I have probably a hundred commerical DVDs and I am not aware of even one of them that is CBR encoded. I don't doubt their existance, but I would expect them to be quite rare. Observing their bitrate using PowerDVD and bitrate viewer, they tend to on average to fluctuate between 4-6Mb/s and occasionally spike higher and lower than that.
Secondly, I never encode CBR even if there is plenty of room, I encode a 1 pass VBR quality-based encode at maximum quality. The benefit is it takes less room on the disk (so it burns/authors faster) while theoretically maintains the same quality as full bit-rate CBR and encoding at the same speed as CBR. In fact, I encoded 48 minutes of NSTC 29.97 D1 footage at max quality-based VBR MPEG-2 encode/192Kbps AC-3 audio and it took 1.76GB. I could have encoded the video at "9.3Mb/s" CBR MPEG-2 and really gained nothing, but perhaps even lost something in compatibility!
When there is a question of a 1-pass VBR max quality encode possibly being too big to fit on a SL DVD-R, then I go to regular VBR based encode and set the max/min bitrates depending on the footage length.
Finally, here's an interesting article.
http://www.emedialive.com/Articles/R...8309&PageNum=2
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There are two modes of DVD encoding, constant bit rate (CBR), and variable bit rate (VBR). When encoding in constant bit rate mode, the level of compression difficulty or motion within the video stream is irrelevant, because the same bit rate is used throughout the entire process. So a static talking-head segment of a given video project will be compressed at the same bit rate as dynamic, high-motion scenes, which does a disservice to both and makes inefficient use of the disc's overall bit budget. Most home videos are encoded in CBR because it is quick and less complicated. (Most entry-level tools don't even include VBR encoders.) So the quality of the final product is consequently compromised. According to DVD author Richard Diercks, "No professional video should be encoded in constant bit rate (CBR), even if bandwidth is high. Our experience is that variable bit rate (VBR) always looks better."
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