针对qt4的(视频格式为rgb32)
v4l_grab_movie(&v4l_dev);
unsigned char *pBuffer= v4l_dev.buffer;
QImage image(pBuffer,320,240,QImage::Format_RGB32);
QPixmap pixmap;
pixmap=pixmap.fromImage(image);
label->setPixmap(pixmap);
label->setFixedSize(pixmap.width(),pixmap.height());