$ /Applications/Video/mp4box_EvalVid/MP4Box -h extract
Extracting Options
-raw TrackID: extracts track in raw format when supported
-raws TrackID: extract each track sample to a file
* Note: "TrackID:N" extracts Nth sample
-nhnt TrackID: extracts track in nhnt format
-nhml TrackID: extracts track in nhml format (XML nhnt).
* Note: "-nhml +TrackID" for full dump
-single TrackID: extracts track to a new mp4 file
-avi TrackID: extracts visual track to an avi file
-qcp TrackID: same as '-raw' but defaults to QCP file for EVRC/SMV
-aviraw TK: extracts AVI track in raw format
$TK can be one of "video" "audio" "audioN"
-saf: remux file to SAF multiplex
* Note: can be used when encoding scene descriptions