I'm looking for a lossless audio codec to capture video. The codec must be
available from the video capture software(s), thus it must be integrated and
be available in my WindowsXP lists of codecs. It must be capable of
compressing 48khz sampling rate.

I use various software to capture/process HuffYUV video such as VirtualDub
1.5.9, Adobe Premiere 6.0, Sonic Foundry Vegas 4.0. Once the processing
done, I use TMPGenc Plus 2.59 to compress the high quality final to MPEG1.

I installed various lossless audio codecs such as FLAC 1.1.0, Monkey 3.97,
La 0.4 and Shorten 2.3b. These codecs work only in command-line or GUI
software. Their codecs don't appear in other video/audio processing
software. Thus can't be called by other software, so they are pretty much
useless for me.

I want to use a lossless audio as an "intermediate" codec. (much like I use
lossless HuffYUV codec for the video track). Presently I capture the audio
track of the video in PCM audio at 48kHz, 16-bit, Stereo. Multiplied this by
8 hours of capture + another 8 hours to process. At this my secondary 80Gig
HD runs out of space in no time.... 50% audio compression would satisfy me.