[MPlayer-dev-eng] Overlay Video/Image) on top of Mplayer

[Sriraman G]

Hi masters,
   i am totally confused with the term overlay.(a declaimer before
starting :) ).

i had a program which uses vf_overlay (a.k.a bmovl,bovl2,vf_osd) to
draw things on top of mplayer video. I had written that program around
1 year back (i was using program to overlay images and video-in
video). What vf_overlay does is it mixes the external image with
mplayer decoded frames. The process is bit expensive because it has
got (YUV > RGBA -mixing - RGBA > YUV) conversion. Also one of the draw
back is the overlaid stuff will get scaled with video scaling.
    To fine tune the program i am looking for some other work around,
on the way i found about hardware overlays,
Could any one plz help me how i can take use of hardware overlay to
improve my video mixing program?
 (I have a NVIDIA geForce which supports overlay)... from the XV
documentation i found that there is a function like BlittImage()..and
all also there is concept of port which i am not clear about.. i
searched a lot for information (for the last few months i am digging
the net). Could please some send me at least some good links so that i
can read and understand how i can take use of that..

Also, i found abt colokey in the man pages. (even though u don't have
any practical knowledge with this, i think that using colorkey will
give us option put things over a playing video but it can't prove
alpha (semi transparency).

Thanks in advance
Sriraman
sriraman.krishna at gmail.com