Computers that play Blu-Ray discs have to deal with High-Definition Copy Protection (HDCP). This is a system involving both software but also hardware chips that are placed in equipment that might be used to play Blu-Ray content. Because the manufacturers of blue Ray discs do not want unauthorized copy of their material, and because digital copying is the worse for them since no quality is lost and mass copying is easier to accomplish, manufacturers place HDCP on Blu-Ray discs frequently. These should HDCP copy protection is more common at this time than when Blu-Ray first came out.
The HDCP system is easy to understand and it is annoying. If a Blu-Ray disc is manufactured with HDCP copy protection, then when it is played the Blu-Ray disc asks the player whether the player, and every other device in the signal transmission train has a little HDCP chip in it. This is something the manufacturer had to build in. The devices that must have this chip are the Blu-Ray player itself, video card, any switches that switch the video before it gets to the monitor or the TV, and the monitor or the TV itself. If a Blu-Ray disc with HDCP is played on a simple set top Blu-Ray player then that player as well as a TV also must to have this chip.
If an HDCP encoded disc is played on equipment without the chip-that is not "HDCP compliant"- the disc either will not play or will play with reduced video resolution,or may play without the fancier types of audio-play in simple two channel stereo rather than 7.1
Additionally the single chain must be all digital. If HDCP compliant equipment is connected together with any analog connectors then Blu-Ray's with this copy protection will not play. The most common place this will occur is connecting into the monitor. If playing from a computer, using the DVI or HDMI cable is necessary. The old-fashioned analog computer monitor cable will transmit the image to the monitor well but will disrupt the copy protection. Similarly set top Blu-Ray players which are connected to the monitor or TV using the composite connectors-the three red blue and green jacks-will disrupt the copy protection. The high-definition image will get through on non-copy protected material however. If all of the equipment is HDCP compliant than switching over to a DVI or HDMI cable is all that is needed under these two circumstances.
The situation is a little bit more complicated if there are two monitors. Most of the time as long as one of these is HDCP compliant -- and is connected with a digital cable -- the discs will play. Sometimes the window playing the Blu-Ray material can even be played on the analog monitor.
Usually the documentation of each piece will state that it is HDCP compliant. Sometimes checking that is what's needed to determine which part might need to be replaced.
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