cut from image without loading

i have a so big JPG image. It's about 1GByte. And i need to cut/clip subimage among (x1,y1,x2,y2) coordinates without loading full image. Maybe it can be made on lower level programming. e.g. by studying JPEG File Format, but i need higher level code, or Components ..,pls help me
[295 byte] By [OttScreenNamea] at [2007-10-2 4:04:33]
# 1
I think ImageReadParam.setSourceRegion() does the trick.
itchyscratchya at 2007-7-15 23:27:12 > top of Java-index,Security,Cryptography...
# 2
great. Thank you so much!!!
OttScreenNamea at 2007-7-15 23:27:12 > top of Java-index,Security,Cryptography...