Hydrogenaudio Forums > Nero AAC -br vs. -cbr

Hydrogenaudio Forums > Lossy Audio Compression > AAC > AAC - General

Heiko242

Jun 3 2008, 02:20

Hi guys,

could someone explain the difference between the switches -br and -cbr in Nero AAC?

-br <number> : Specifies "target bitrate" mode.
<number> is target bitrate in bits per second.
-cbr <number> : Specifies "target bitrate (streaming)" mode.
<number> is target bitrate in bits per second.

Sorry for the dumb question.

Nick E

Jun 3 2008, 03:40

QUOTE(Heiko242 @ Jun 3 2008, 02:20)

Hi guys,

could someone explain the difference between the switches -br and -cbr in Nero AAC?

The -cbr switch seems to be for CBR (Constant Bit Rate) and the -br switch for ABR (Average Bit Rate).

That's what's said here in the sticky note on config:

http://www.hydrogenaudio.org/forums/index....showtopic=44310

QUOTE

Using VBR mode (-q) will give the best quality. The default setting is -q 0.5, which will give about 160-170kbps on average. For ABR, use the -br options. For CBR, use -cbr. Note that the bitrate is in bits per second, not kilobits.

memomai

Jun 11 2008, 02:24

the cbr mode is not exactly a constant bitrate. You'll see in decoding process, that the bitrate is variable around 3 or 4 kbits around the specified bitrate.

the nero aac codec is optimized for VBR mode, like every other modern lossy codec. The -cbr switch is useful for example internet streaming, because the bitrate stays in the specified kbps area. The ABR mode has more freedom in taking less or more bits per second depending on the complexity of the music / sound file, but it tries to stay in your specified kpbs area. It may be useful if you want to create a filesize for your needs.

Gabriel

Jun 11 2008, 04:53

Once again, CBR does not mean that every frame will use the exact same amount of bits.

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