The following information is provided as is, and the authors take no responsibility for the correctness.

$ foo2lava-wrapper -z1 testpage.ps | opldecode |more
Event=StartOfJob;
OSVersion=Linux;
DrvVersion=2.0.1410.0;
Resolution=1200x600;
RasterObject.Compression=JBIG;
Sides=OneSided;
MediaSize=na_letter_8.5x11in;
MediaType=plain;
MediaInputTrayCheck=top;
RasterObject.BitsPerPixel=1;
RasterObject.Planes=000000,0,0,0,0,0,0;
RasterObject.Width=9792;
RasterObject.Height=6400;
RasterObject.Data#20=

                        DL = 0, D = 0, P = 1, - = 0, XY = 9792 x 6400
                        L0 = 128, MX = 0, MY = 0
                        Order   = 3  ILEAVE SMID
                        Options = 92  LRLTWO TPDON TPBON DPON
                        50 stripes, 0 layers, 1 planes
RasterObject.Data#32768=
RasterObject.Data#32768=
RasterObject.Data#32768=
RasterObject.Data#32768=
RasterObject.Data#32768=
RasterObject.Data#6432=
Event=EndOfPage;
Event=EndOfJob;

References http://foo2lava.rkkda.com