1.What is overlay? In my V4L programing ,I read some demo programs such as xawtv. I find ,in xawtv's source code, the capture mode can be divided to two kinds .One is capture ,the other is overlay . And I also find the following in videodev.h #define VID_TYPE_CAPTURE 1 /* Can capture */ #define VID_TYPE_OVERLAY 8 /* Overlay onto frame buffer */ I cannot understand what is difference. 2./dev/video0 cannot be opened multiple times this question has been asked in another previous post .but now I cannot get the answer . 3./dev/video0 cannot be set param mutiple times when I open the /dev/video0 first , I can set mmap mode ,and set grab size for ioctl(..VIDIOCMCAPTURE..). but if I want to change the grab size ,I use the same code to set grab size for ioctl(..VIDIOCMCAPTURE..) ,I will get erro. what lead to this ? can you give me some hints? __________________________________________________ Do You Yahoo!? Yahoo! - Official partner of 2002 FIFA World Cup http://fifaworldcup.yahoo.com
