做基于达芬奇平台SEED DVS6446视频采集回放实验，在超级终端显示运行无错误，但是采集不到图像，显示屏是漆黑一片，是什么原因，哪位高手知道，请多多指教。具体操作流程如下：
192.168.1.100 login: root
Last login: Sat Jan  1 00:04:56 2000 on console
Linux 192.168.1.100 2.6.10_mvl401-davinci_evm #47 Tue Oct 19 06:11:52 CST 2010 a
rmv5tejl GNU/Linux

Welcome to MontaVista(R) Linux(R) Professional Edition 4.0 (0501140).

root@192.168.1.100:~# cd /opt/seed_exp
root@192.168.1.100:/opt/seed_exp# ./loadmodules.sh
cmemk: module license '(c) Texas Instruments' taints kernel.
cmem initialized 4 pools between 0x83c00000 and 0x84400000
dsplinkk: no version for "struct_module" found: kernel tainted.
DDR_START 0x87600000 DDR_SIZE 0x800000
root@192.168.1.100:/opt/seed_exp# ./unloadmodules.sh
root@192.168.1.100:/opt/seed_exp# ./loadmodules.sh
cmem initialized 4 pools between 0x83c00000 and 0x84400000
DDR_START 0x87600000 DDR_SIZE 0x800000
root@192.168.1.100:/opt/seed_exp# ./video_app
loopback demo started.
Capturing 720x576 video.