Added sample-aspect-ratio (SAR) detection for DV streams. Kludgey right now,
and does nothing for any other LAV input file types. Also, added "-A w:h" command-line option to lav2yuv to specify/override SAR.
(And, small usage print-out fix to y4mcolorbars.)
Authored by: mdoggydog 2001-12-10
Parent: [r1041]
Child: [r1043]
