A small device that allows one to increase the number of output signals generated by their source so they can connect more than one display. HDMI splitters are relatively competitively priced devices, with a slight variation depending on how many screens it can connect.

Uses of an HDMI splitter

If you have a single source but multiple screens an HDMI splitter can help solve this issue for you. You will be able to watch the same movie or presentation on multiple screens. HDMI splitters take the source signal and send the exact same signal to all the connected displays. 

Possible issue

As the signal is digital it can be copied without loss, the quality of transmission is consistent. For this to be true in effect the HDMI splitter has to be of good quality or you will notice lack of audio and visual clarity.

Given HDMI splitters are able to form digital handshakes, the splitter can read and match the signal of each display. But this requires the splitter to send out an identical signal to all the displays. This also means that if one has 2 displays that are of a different resolution the HDMI splitter will send an output signal at the lowest common denominator. For instance, if one screen is 1080pand the other is 720p, the splitter will send 720p to both. A way to eradicate this is to use an HDMI downscaler between the lower-resolution display and splitter. The downscaler will receive the 1080p signal and downscale it for the 720p display without it being realised by the splitter. In effect, this fools the splitter and it keeps sending the 1080p signal to all displays.

HDMI splitters are relatively inexpensive devices. A splitter with more out-ports or of better quality will be from a higher price point, of course.