You'd be better off capturing as a DV-AVI (avg 10:1 compression). The compression is still lossy, but not nearly as lossy as MPEG2 (avg 40:1)
AVI is just a file format, it doesn't have a particular standard compression method associated with it. Lossless AVI uses RGB or YUV no compression formats or HuffYUV which gives about a 4 :1 compression ratio.
Fav quote - "Experience is whatcha don't get 'till ya don't need it no more."
System - Athlon 1.4GHz, Win98, Hauppauge PVR250 receiver and compressor.
Software -Magix Movie Edit Pro 10, Nero 6 + NeroVision Express, Moho 4.61, PSP 8.1, Bryce, Quicktime 6.52 pro, Goldwave 5, DVD-Lab.
Cameras - Panasonic GS9, Canon ES8400V, Canon EOS D20 and Canon A70