I ask the following just for understanding the music quality as a result of OGG encoding. I noticed some time ago (when I LAME'd my CDs to MP3s), that LAME and a setting "alt preset std" would essentially sense the quality of a poor recording and fall back to 128kbps (... when it would otherwise encode VBR with an average ~160).

This can be noticed if you RIP something like Billie Holiday. For example, if I RIP a Fats Waller 3 minute tune ... for OGG settings '6', '4.9', and for LAME, I get resulting files sizes of 2984, 2306 and 2811 respectively. Playing the music results in indiscernable listening difference, and apparent kbps of ~145, ~110 and 128.

I wonder ... (1) is there development room for OGG to "sense" the quality and to fall back to an appropriate (apparent) kbps? ... or ... (2) is OGG "sensing" better quality in the recording than is LAME??

Hi,
I don't think you should worry about the bitrate too much.

There's no such thing as "quality sensing" in any audio encoder I know of.
When using VBR, they simply choose a sufficient bitrate for accurate encoding, so the drop in bitrate is certainly because of the recordings being near-mono.

This can also happen with the following kinds of signals:
- near-silent
- highly redundant
- empty frequency subbands (should not happen in regular music, especially for the higher bands).

Cheers