In essence you can use any PC with the operating system of your choice. The most common operating systems to choose from are; Porteus Kiosk, Windows or Linux.
As a general rule of thumb, when choosing any computer for signage playback we recommend choosing one with a processor with a Passmark CPU Mark of at least 1500, preferably over 2000. If you go below 1500, it highly depends on the efficiency of the rest of the components, the operating system and the quality of the drivers (especially the video drivers) how smooth the playback will be.