Is there any way for me to downsample and go mono before encoding WMA without consuming much CPU and changing the samplerate and for the other encoders I have running on the same channel, "under the same Bass recorder"?
I got lost what you are trying to do. ;-)
You want to downsample without changing the samplerate?
-> Downsampling involves changing the samplerate!
-> However, resampling is supported via BASSmix, e.g. change a stream from 44.1kHz to 22.05kHz
-> Same is with going from stereo to mono. This can be done via Matrix Mixing
I belived that WMA accepted higher samplerate and downsample it self
-> Have you tried this with BASSwma already?
Regarding VBR vs. CBR detection:
There is not much what BASS.NET could do, since BASS.NET does not do the actual frame header parsing.
BASS is doing the decoding of MP3 frames and so only BASS could give such information.
However, the issue is, that there is no clear standrad about a VBR header in the frames.
Some encoders write "Xing", some "VBRI" etc.
See this post for more details:
https://www.un4seen.com/forum/?topic=5034.msg33620;hl=vbr;topicseen#msg33620