iPod Basic question about VBR

GanChan

macrumors 6502a
Original poster
Jun 21, 2005
590
24
Newb question....I imported several CD tracks today with my iTunes set to mp3, 192 VBR, normal Stereo. When I checked the bit rates of the finished files I noticed that while none of the tracks were less than 192, some were up around 197 or 198. So far, so good. My question is: How high above 192 would iTunes theoretically let a track go, with my current settings?
 

BlizzardBomb

macrumors 68030
Jun 15, 2005
2,537
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England
At a 192kbps VBR, the 192kbps is your guaranteed minumum bitrate. Therefore, you will never get a bitrate lower than 192kbps.

If you didn't know already VBR stands for Variable Bitrate. This means for louder sounds, it will increase the bitrate and for the quiet bits, it will lower the bitrate. So if your song is something with really heavy or loud sounds, you will find the bitrate to be higher than a relaxing or gentle tune. The bitrate you get at the end is an average of the whole song and this makes it hard to predict what bitrate it will be.
 

GanChan

macrumors 6502a
Original poster
Jun 21, 2005
590
24
BlizzardBomb said:
At a 192kbps VBR, the 192kbps is your guaranteed minumum bitrate. Therefore, you will never get a bitrate lower than 192kbps.

If you didn't know already VBR stands for Variable Bitrate. This means for louder sounds, it will increase the bitrate and for the quiet bits, it will lower the bitrate. So if your song is something with really heavy or loud sounds, you will find the bitrate to be higher than a relaxing or gentle tune. The bitrate you get at the end is an average of the whole song and this makes it hard to predict what bitrate it will be.
Let me rephrase: In a variable-bitrate configuration, how high above 192 would my encoding possibly allow itself to go in a particularly loud moment? 320? 256? No limit? In other words, how is the RANGE of the variation determined?
 

ham_man

macrumors 68020
Jan 21, 2005
2,265
0
Theorectically (spelling, I know), the bitrate could go as high as 320 kbps. However, on iTunes 192 VBR on the normal setting, I would not expect anything above 201 or 202. Hope that answers your question...