MPEG tools in TMPGEnc

[compusic]

The MPEG tools have multiplex function, there's one thing strange. In the type option there's "mpeg-2 program" which is followed by "VBR". since I let the tools multiplex CBR stream without any problem, I wonder why only "VBR" is showed here ( there's no "CBR" listed here)?

[Mug Funky]

the bitrate even in CBR "breathes" a little. mpeg-2 is inherently VBR (so is mpeg-1 really, but must usually be muxed at a constant rate unlike mpeg-2).