Won't play the following video, audio works fine

I have a MPEG4 video in an MKV container, but it won’t play the video, just black screen. Audio is working though.

The data for the video are this:

Format : MPEG-4 Visual
Codec ID/Info : Advanced Simple Profile
Duration : 1h 13mn
Bit rate : 1 169 Kbps
Width : 640 pixels
Height : 352 pixels
Display aspect ratio : 16:9
Frame rate mode : Constant
Frame rate : 23.976 fps
Compression mode : Lossy
Bits/(Pixel*Frame) : 0.216
Stream size : 614 MiB (88%)
Default : Yes
Forced : No

Edit:  I’m using the current firmware 1.07.18 on the WD TV Live SMP.

Nothing seems to be worng with the encoding.  You may try playing back the file from a USB drive.  You can also reset the SMP by holding its reset button for 1 second, if issue persists try re-encoding your file with a different software.