I added "Qt for Embedded Linux example application" to configure. And I remade rootfs.
But, there are no libQtMultimedia* in /build/rootfs/lib/.
I copied DigiEL-5.9/x-tools/arm-cortex_a8-linux-gnueabi/arm-cortex_a8-linux-gnueabi/sysroot/usr/lib/libQtMultimedia* in /build/rootfs/lib/.
I operated "Video Graphics Item Example" and "Video Widget Example".
An error disappeared.
The frame was displayed, but a picture is not displayed.