Soft video encoder for M4
THere seems to be a lot of info on QVGA and not so much on VGA
http://www.codeforge.com/s/0/STM32F4-VGA-320x200-256-colors-keil

But this brochure has some info

With a 48MHz PIXCLK and 8-bit parallel input data interface it is possible to receive:
 - up to 15fps uncompressed data stream in SXGA resolution(1280x1024) with 16-bit per pixel
 - up to 30fps uncompressed data stream in VGA resolution (640x480)with 16-bit per pixel