If you are only reporting, OK.

If you ask for help, then "... and so on..." is not enough. Copy all the output text from running mplayer to where it is available and post a link.

No video - did you run mplayer as root, or made sure the user has permission to access (rw) the /dev/s3c-* files?

No audio - by default the speaker is disabled, either use headphones, or insert and remove headphones (which enables the speaker), or enable it by

echo 1 > /sys/devices/platform/hhtech_gpio/speaker_en