HDMI Trouble

HDMI high-speed interface has now become common products are widely used in various kinds of digital equipment, including audio-visual equipment sorts of TV and Blu-ray Disc players, smartphones and mobile range of digital cameras, as well as PCs and monitors. 

Does not feel 8 years have passed since the HDMI was first introduced to the world. But over time, many complaints began to appear about the damage to the HDMI. At the time confirmed at Minoru Ohara, president and CEO of Allion Japan Inc., 

he said that it was a lot of damage or defects found during testing HDMI. Details of the authentication tests including HDMI specification unfortunately kept secret, but essentially, when the composition of the HDMI tentatively divided into "physical layer" and "logical layer," the second layer was found to have problems.

Problems in the Physical Layer

Physical layer consists of cables, connectors and circuitry for processing electrical signals. While the logical layer is used for the process of encoding, processing the data packet video / audio, read EDID (extended display identification data), exchange CEC (consumer electronics control) data and so on. Most problems in the physical layer due to cable impedance lines and the source device. When a problem occurs at the physical layer, for example, there will be no image displayed on the screen or blink occurred.

Because HDMI kabeltingkat require high transmission, the cable passed the authentication test does not pose a problem. However, in the market, there are some cheap cable that is claimed to be compatible with HDMI even though they do not pass the exam. 

The cable is exactly what caused the problem. Especially, when the length of the cable reaches 10m or more, sometimes drastically deteriorated transmission quality .... Examples of the causes of the problems associated with line impedance of the diode clamp is used to protect the HPD (Hot Plug Detect) and the circuit board embedded in the source devices such as Blu-ray Disc player to support the HPD from the HDMI. Line impedance fluctuates due to the capacitance diode.

Problems In Logical Layer

Damage to the logical layer associated with the function "CEC" to control other devices connected via HDMI. With the CEC, the optical device can now be controlled using the TV remote, but sometimes the process fails.

CEC sometimes result in problems since the specification essentially been replaced and new functionality added to it along with various updates HDMI specification. Not to mention there berbai kinds of differences between the specifications of the HDMI CEC specification. 

Some manufacturers even add their own extensions to the CEC, which is named so-and-so link. It is making the situation worse, because the source range of device manufacturers and manufacturers of optical disc device such as a TV sync use the same path, so the problem on the CEC will have a greater possibility. However, if the path used separately, CEC sometimes it does not work.

HDCP (high bandwidth digital content protection)

HDCP and HDMI have different independent standards. So HDMI does not always have to support HDCP. However, DVD players (source) and TV (sync), which relates to video content, must support HDCP to protect copyrights. Several kinds of digital equipment camcorders, digital cameras, mobile phones, and so forth, does not support HDCP. So, when two devices are compatible with the HDMI connected and one of them does not support HDCP, it would appear an error message "It does not support HDCP". 

This kind of error is not considered a problem due to the HDMI, since HDMI specification does not currently need to have compatibility with HDCP. However, for the user it is a nuisance. Will still need to be considered that are not defective in terms of specification but users consider it a flaw.