My guess would be when you change the minimum bitrate to -b192 that the encoder uses the bit reservoir more liberally in an attempt to not balloon the size up as much since it can not use smaller than 192kbps frames.
When using LAME in VBR mode, setting a low bitrate minimum doesn't affect audio quality. The minimum bitrate setting is used after encoding the frame, when audio data gets packaged into sufficient sized frames.
*NOTE* No psy-model is perfect, so there can often be distortion whichis audible even though the psy-model claims it is not! Thus using asmall minimum bitrate can result in some aggressive compression andaudible distortion even with -V 0. Thus using -V 0 does not soundbetter than a fixed 256 kbps encoding. For example: suppose in the 1 kHzfrequency band the psy-model claims 20 dB of distortion will not bedetectable by the human ear, so LAME VBR-0 will compress thatfrequency band as much as possible and introduce at most 20 dB ofdistortion. Using a fixed 256 kbps framesize, LAME could end upintroducing only 2 dB of distortion. If the psy-model was correct,they will both sound the same. If the psy-model was wrong, the VBR-0result can sound worse.
[lossy codec] for the overly paranoid.
When using LAME in VBR mode, setting a low bitrate minimum doesn't affect audio quality.
How big can the reservoir become? Is it even possible to add it to 320kbit frames?
Only thing I do't understand: why is audio data stream not exactly the same when using -Vx -b nnn as with plain -Vx? (I tried last night - foobar said that there is a difference, and peak difference isn't small).
Since LAME can occasionally select the wrong bitrate in VBR mode, it seems like it would be a good failsafe to allow such a behaviour "just in case" and for the overly paranoid.
I've been experimenting with various VBR options, and I'm slightly confused as to how LAME decides what birate to use for each frame. As I understand it, LAME will try different bitrates and select the lowest bitrate that achieves acceptable quality.
Quote from: halb27 on 22 March, 2010, 04:03:24 AMOnly thing I do't understand: why is audio data stream not exactly the same when using -Vx -b nnn as with plain -Vx? (I tried last night - foobar said that there is a difference, and peak difference isn't small).What onkl said.
I was talking about potential quality impovement on (rare) occasion of -V0 -b 320 | mp3packer over plain -V0. Bitrate of these variants are nearly identical on average.
-V0 can produce better quality than CBR320 with specific samples
Largest frame uses 10976 bits = 1372 bytes = 420.175000 kbps