get the "xine-lib" source code, untar the source pack, in directory misc, you can find xine-fontconv.c , compile it as follow:

gcc xine-fontconv.c -o xine-fontconv `freetype-config --cflags --libs` -lz

after then, we get xine-fontconv, so we can use it to generate our own fonts. the format as follow:

./xine-fontconv  fonts.ttf  fontsname [encoding [encoding] [encoding] ... ]

for exampel:
 ./xine-fontconv /usr/share/fonts/zh_CN/TrueType/gbsn00lp.ttf gbsn cp936 gb2312 gbk big5

the above command will generate some font pack, just like gbsn-24.xinefont.gz ..., then copy  these  *.xinefont.gz to /usr/share/xine/libxine1/fonts/

at last, modify the ~/.xine/config file to apply the fonts we just generated. add following sentences:

subtitles.separate.subtitle_size:64
subtitles.separate.vertical_offset:0
subtitles.separate.font:gbsn
subtitles.separate.src_encoding:gb2312


note: you can find these in xine faq