Beginner's Q: Variable Bit Rate

bryanbailey wrote on 2/14/2002, 8:07 PM

Begginer's question: What is the advantage of using VBR to render a file?

Comments

bcbarnes wrote on 2/14/2002, 8:51 PM

There is an advantage in that the bit rate is varied based on the amount of motion in the video being compressed. Higher motion areas are given higher bit rates so that there are less compression artifacts, while lower motion areas are given lower bit rates inorder to decrease the overall size of the file. Compare this to a constant bitrate compression, where bits may be wasted on low motion areas, and high motion areas may not have high enough bit rate and end up with compression artifacts (blockiness). Of course, I would imagine that constant bitrate could provide good compression with videos that have all high motion or low motion, if the bitrate is adjusted correctly.

bryanbailey wrote on 2/14/2002, 8:53 PM

Well, I was reffering to audio, not video.

Baylo wrote on 2/14/2002, 9:22 PM

Same concept, though. High bit rates are only used when needed, thereby reducing the size of the file in comparison to a file compressed at a constant high bit rate.

Mark

sonicboom wrote on 2/15/2002, 1:33 AM

so when i render an audio file, should i render it at the highest quality vbr stereo audio?
thanks, sb