Here's a table of what video (from my motley collection of test files and movie trailers) were viewable on my desktop Mplayer, Mplayer on my tablet, and the Nokia media player on the tablet.
Key: Y yes, N no, Nc codec not supported, Nf format not supported, Nl did not launch, ns no sound, nv no video

file	Nokia media player	Tablet mplayer	Desktop mplayer codec video/audio	aspire mplayer	aspire mediamaster
3gp.3gp	Y	Y	ffodivx/-	need ubvmp4d.dll
bmp24.avi	Nc	N	N ffmsrle/-	Nc
bmp32.avi	Nc	Y	rawbgr32flip/-	Y
cinepak.avi	Nc	Y	ffcvid/-	need vid_cvid.xa
divx.avi	Nf	Y	ffodivx/-	Nc
dv_pal_progressive.avi	Nc	Y	qdv/-	need mcdvd_32.dll
dv_pal_progressive.dv	Nl	Y	qdv/-	N
huffyuv.avi	Nc	Y	ffhuffyuv/-	need huffyuv.dll
indeo.avi	Nc	N	indeo5ds/-	need vid_iv50.xa
mpeg4.mp4	Y	Y	ffodivx/-	need ubvmp4d.dll
qcif_RGBA.avi	Nc	Y	rawbgr32flip/-	Y
qcif_RGB.avi		Y	rawbgr24flip/-	Y
qcif_UYVY.avi		Y	rawuyvy/-	Y
qcif_Y8.avi	Nc	Y	rawy800/-	Y
qcif_YUY2.avi		Y	rawyuy2
qcif_YV12.avi		Y	rawyv12/-
qcif_YV16.avi		N	N YV16
qcif_YVU9.avi	Nc	Y	rawyvu9/-	Y
uncompressed.avi	Nc	Y	rawbgr24flip/-	Y
wmv9.avi	Y	Y ffwmv3	wmv9dmo/-	Y
Animusic-PipeDream.wmv	Y/slo	Y ns	wmv9dmo/wma9dmo	need wmadmod.dll	Y ns
Anna	Y	Y ffodivx/mad	ffodivx/mp3
SteveSw31.mpg	Nl	Y ffmpeg1	mpeg12	Y	Y
toystory.avi	Nc	Y cvid/pcm	ffcvid/pcm	Y
wmvideo.wmv	Nc	Y	wmv8/wmadmo		Y ns
whiterain.ra	Y	no vid	rv3040/ffcook	need drv3.so, cook.so
000_2216.qt	Nl	Y/slow	ffmjpeg/pcm	Y
hakuna1.mov	N	Y/bad	ffcvid/pcm	Y nv
sample_h264_100kbit.mp4	Y	Y	ffh264/faad
robots_m480.mov	Nl	Y/err	ffsvq3/ffqdm2	need qtx codecs, slow
queen-damned_lo.mov	Nl	Y	ffsvq1/ffqdm2	need qtmlClient.dll, QuickTime.qts
misc2.wmv	Nc	Y	wmadmo/dmo
misc	Nl	Y	ffodivx/pcm
misc18.mpg	Nl	Y	mpegpes/mp3 n/sound