Http /Be aware that RedMere cables are directional. a 40 ft (12m) RedMere cable costs about $50 from Monoprice. I don't know what country you're in, but in the U.S. This allows you to make longer cables without using thicker wires. These cost a lot more, but they basically steal some power from the TV, transmit it back to the laptop, and use the extra power to amplify the source signal before it's sent to the TV. The other solution is to get a RedMere cable. Problem with this solution is that you have a thick cable which is unsightly and hard to get around corners (mine is in the attic crawlspace). Return the cable and get a new 10m cable using bigger wires (yours is probably using 28 gauge wires my thick one uses 22 gauge). Since you can't change the laptop's HDMI port, you've got two choices. Your media player is likely pumping out more voltage, enough for the signal to make it to the TV. But not enough is making it through for a picture.
Some of it is getting through so the TV knows something is connected. Likely what is happening is that the laptop just isn't putting out enough power over HDMI for the signal to entirely make it to the TV. But HDMI has so many wires that this is really difficult (the 8m cable I have is nearly as thick as a garden hose).
Normally when you make long cables, you make the wires thick so signal attenuation is minimized. 10 meters is really long as HDMI cables go.
