Players
Televisions.com
Player Articles
First aid for HDMI TV connector cable with common problems and solutions explained.
First aid for HDMI TV connector cable with common problems and solutions explained.
by
Florian Friedrich on 04/05/2009
It's all about HDMI in the TV and home-theater business these days, but this slim-line connector is far from trouble-free. We have some tips and tricks for successfully dealing with the universal interface.
It sounds so practical: One cable for everything - audio, video, and control. But, sadly, HDMI is not as simple as it may appear on first blush. The universal interface can also cause a variety of problems for TV and home-theater users - and once it throws a tantrum, nothing will work correctly. It's no wonder when you consider the sheer number of different manufacturers of HDMI products - there are just bound to be problems. But, what exactly is HDMI?
What is HDMI? And what's the benefit?
The "High Definition Multimedia Interface" is the first fully digital, universal interface for transmitting audio and video data in the consumer-electronics sector. The HDMI connection allows transmission of uncompressed picture and sound data, in a clearly-defined direction: from a "sending device" to a "receiving device". The sending and receiving devices constantly exchange information about which signal to transmit in which standard.
A consortium of chip manufacturers and consumer-electronics companies oversees the development of HDMI technology and issues licenses to companies wanting to use HDMI. Development progress is indicated using version numbers, and each new version number should guarantee backwards compatibility with all previous versions. HDMI combines various picture and sound connections that have existed over the years in to one cable, as well as improving upon the signal quality.
The HDMI logo.
First-ditch problem-fixers:
So far, so good. But, in practice, the system is fraught with difficulties: The sound cuts out, the image flickers or turns blue, the communication doesn't work. So, what now? We've collected together some tricks that we've found very useful in the past:
- Simply remove the cable, plug it back in, and try again.
- It can also be helpful to turn the devices off and then back on again, but in a different order. A different switch-on sequence can solve a number of problems.
- Better yet: Unplug the devices completely from the power supply, and then plug them back in again - this can work wonders.
- Swap the cables around to see if they're contributing to the problem. Even try swapping expensive cables for cheap ones - cheaper doesn't always necessarily mean poorer quality.
- Sometimes it helps to update the devices - similarly to PCs - to the newest firmware version.
- Try increasing the source device's resolution in steps from low (for example, 576i/p) to high (1080p/60).
- If none of these tricks fix the problem, you can always get some advice from an expert dealer.
HDMI is just a type of socket. The electronics behind it define what the connection can transmit and receive.
Tell the manufacturer!
Many frustrated customers have given up trying to contact manufacturers' hotlines and service addresses, which are often unable to deal with the full complexities of HDMI technology. The manufacturers' test labs are also often very slow to respond.
Nevertheless, you should try to inform the company of your specific problems, so that they may be able to take them into consideration in future upgrades. Without sufficient feedback, they won't be able to produce useful upgrades!
Well-known problems:
Handshake difficulties:
The mutual greeting between the devices (the so-called "handshake") is a critical moment for HDMI communication. If it works correctly, nothing else will generally go wrong. If the handshake doesn't work, try the tricks we mentioned above.
Problems with the HDCP copy-protection:
Every HDMI receiving device has to support High-bandwidth Digital Content Protection (HDCP), but some versions of sending devices do not have HDCP - some digital cameras, for example. The copy-protection uses a video-signal encryption that's produced by the sending device, and which the receiving device decrypts with the help of a code.
The source device checks at regular intervals to see if the receiving device is still there - if it doesn't get an answer, it stops transmitting the video signal. If there's a communication problem between the devices, either you'll not see a picture or you'll just see snow. Generally, a new handshake will help to solve the problem - at least, that is, if both sides conform to HDCP.
Picture errors:
Interference in the picture can come from an external source, such as radio waves or magnetic fields; this is most likely to occur if your cables are too long. With a bit of luck, simply changing the layout of the cables may help to resolve this kind of picture error. To test if the interference is external, try standing the devices directly beside one another and connecting them with as short an HDMI cable as possible.
Difficulties with AV receivers, switchers, and amplifiers:
All kinds of problems can occur in the home-theater when relaying, switching or amplifying HDMI signals. For Mr. Normal User, it's virtually impossible to track down the error in these complex processes. Only specialists can do this, since they will analyze the signals precisely. Nevertheless, we've got another tip for you: Always make sure your software is up to date, and try different components until you find a combination that works seamlessly.
Many dealers are quite cooperative, and will allow potential customers to try out various devices - they're more than aware of the problems of HDMI communication. Using a cable that's too long can also cause trouble - the problems become particularly critical above 10 meters. In this case, the best plan is generally to use two shorter cables with a repeater in the middle.
AV amplifiers, such as the Yamaha DSP-Z11, not only have to relay HDMI signals, but also decode and re-encode them.
Different HDMI versions:
The various HDMI versions rarely cause technical problems, but their properties - and above all those of HDMI 1.3 - have repeatedly led to misunderstandings for consumers. When version 1.3 was introduced, many got the false impression that this version defined specific device properties - this simply isn't the case.
HDMI 1.3 says nothing about the device itself; rather, it is nothing more than a catalog of definitions that were being introduced to the standard. The result: Many consumers are confused and don't know which devices they can safely buy.
Digg
del.icio.us
Reddit
Google