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CBR vs VBR vs ABR

CBR, VBR, and ABR are different ways of controlling bitrate. The best choice depends on whether you care most about compatibility, quality, or predictable file size.

Overview

A bitrate mode is not a codec by itself. It is a control strategy used by an encoder. MP3, AAC, Opus, and video codecs all have their own rate-control behaviours, but the same broad ideas appear again and again.

Comparison table

ModeMeaningStrengthTrade-off
CBRConstant bitrate.Predictable and simple.Can waste bits on easy sections or starve hard ones.
VBRVariable bitrate, usually quality-guided.Efficient quality for music and storage.Final size is less predictable.
ABRAverage bitrate target.Balances file-size predictability with local flexibility.Usually less directly quality-focused than VBR.

Which to choose

MP3 examples

lame -V2 input.wav output.mp3
lame --abr 192 input.wav output.mp3
lame -b 320 input.wav output.mp3

For LAME MP3 specifically, -V settings are common for VBR, --abr selects average-bitrate mode, and -b by itself is commonly used for CBR-style fixed bitrate encoding.