Moderator: Captain Ned
ffmpeg -i [input.mp4] -vn -codec copy [output.m4a]
This can be done with a program like YAMB. If using YAMB, just go to the "Editing" section and then double-click "Click to extract streams from...," choose your input file, choose the desired audio stream, and under options tell YAMB to "Excract to MP4." If you need it to be an M4A file for some reason, you just have to rename it..
And as far as lossless goes, there is some argument that it is getting more and more unnecessary to depend on it to achieve optimal sound fidelity. First, as mp3/ogg/apple compression algorithms get better, the differences between, say a 256k lossy file and, say, FLAC, becomes more and more esoteric.
Secondly, there are apparently some cases where, say, the 256k encoded music you get directly from iTunes may even give you better fidelity than buying the CD and ripping to FLAC or other losseless formats. Apparently, this is because iTunes (and maybe some other stores) get at least some of their music content from higher quality/bitrate masters (from which a CD is also made). Now, if iTunes would use lossless codecs to begin with, this would be even better... One can dream.