Why the need for a new connector?
HDMI (High Definition Multimedia Interface), the highly touted but much maligned next generation audio/video connection has been around since late 2002. It is the evolution of the Digital Video Interface (DVI).
DVI is now used on modern computer monitors and graphics cards. There were also a number of consumer televisions and home theatre projectors released with DVI inputs. The good news is that HDMI is backwards compatible with DVI, the bad news is it won’t work 100 percent of the time (more on this later).
It used to be that hooking up a home theatre involved three cables; one for video and two for audio. The advent of the DVD format made the home theatre a realistic option to movie theatres, but it also made things more complex to install. We reached the point where attaining the highest quality audio and video required a component cable with three(!) connections for the video signal and up to eight(!!) cables for audio. And that’s just from a DVD player to an AV receiver. Now add the cables from receiver to TV, cable box to receiver and a gaming console or two, not to mention a dedicated CD or universal disc player. The snake pit of cables behind many home theatre racks would give Indiana Jones a heart attack.
HDMI is a consumer friendly connection that simplifies and improves the home theatre. One cable, that carries both audio and video signals, can do the job that previously required up to eleven separate cables. The high bandwidth of HDMI allows for transmission of up to 1080p content (component cables top out at 1080i). Since the HDMI signal is purely digital, it eliminates the quality degradation in the digital to analogue (and back again) conversion process. There is also no interference within the cable itself. Two-way communication (of device command controls) is supported, which can greatly ease the configuration and operation of multiple HDMI devices.
Although component cables do have the bandwidth to carry high definition video (up to 1080i), content providers like movie studios, didn’t want to give consumers (or pirates) an easy route for copying high definition movies. With High-bandwidth Digital Content Protection (HDCP) as part of the HDMI specification, consumers could now enjoy up-conversion of standard DVDs and the high-def content of Blu-ray without easily being able to duplicate high definition copyrighted material, and thus keeping the movie studios happy.
Another benefit is that HDMI has been accepted as a worldwide standard. This means that new consumer electronics will all have the same connector regardless of what country or region they are manufactured for.
Versions of HDMI
The HDMI format is a great advancement for the home theatre, however its implementation has been somewhat messy. Currently, five different versions of HDMI can be found in various audio and video components.
Versions 1.0 to 1.2
There have been incremental improvements to the initial release of HDMI 1.0. DVD-Audio support was a major feature added to version 1.1. But it wasn’t until HDMI 1.2 that SACD support was introduced. Hence, high resolution multi-channel music lovers had to wait until the release of HDMI 1.2 to fully enjoy their music collections via a single cable. It also became abundantly clear that PCs were becoming more integrated into the home theatre and so HDMI included better support for PC connectivity.
Then in June of 2006, HDMI 1.3 arrived. Push for the upgrade from version 1.2 came from the imminent arrival of the HD DVD and Blu-ray formats. One of the first products to support HDMI 1.3 was Sony’s PS3.
HDMI version 1.3 doubles the bandwidth from 165 MHz to 340 MHz. This translates into an increase in bitrate from 4.9 Gbps to 10.2 Gbps, allowing the maximum bit depth of colour to go from 8 bits per channel to 16 bits per channel. While previous versions of HDMI allowed for a maximum of 17 million colours, HDMI 1.3 allows for 2800 Trillion colours, or Deep Color as the marketing gurus have dubbed it.
Video refresh rate capability of up to 120 Hz is also an upgrade over the 60 Hz of previous HDMI versions. And even though it’s way in the distance, HDMI 1.3 also supports the 1440p resolution.
To top it all off, HMDI 1.3 also supports the much anticipated lossless audio formats Dolby TrueHD and DTS-HD Master Audio.
Finally, there is HDMI version 1.4. The specifications for this version were finalized in August 2009, with products supporting this version expected to appear in stores in mid-2010. The upgrades in this version include: video support for up to four times the current 1080p resolution, 3D support, Ethernet over HDMI and an even wider colour gamut/range.
HDMI 1.4 supports two new video resolutions: 4096 x 2160 at 24 Hz [which is four times 1080p] and 3840 x 2160 at 24 Hz, 25 Hz and 30 Hz.
The integrated Ethernet channel, up to 100Mbps, will allow components to share Internet access. For example, in the future an AV receiver could be the new Internet hub/router, distributing online content to other home theatre components.
But perhaps the most exciting addition is the support for three different methods of 3D imaging. These include frame alternative, line alternative and field alternative. There is also support for side by side [half 2D, half 3D] and 2D plus depth.
Other new features include an audio return channel which will allow TV sets to send audio for decoding [from cable or Blu-Ray, etc] and extended colour space support for sYCC601, Adobe RGB and Adobe YCC601.
And last but not least HDMI 1.4 will introduce two new connectors, in addition to the existing connector. There include an HDMI Micro connector (19-pin, designated “Type D”) and an HDMI Automotive Connection (“Type E”).
Which version do you need?
Do you need the latest version of HDMI to enjoy high definition video and audio? No.
Even though Deep Color capable displays are starting to trickle out, high-def movies encoded with Deep Color aren’t on the market. And even if they were, you’d still be able to enjoy Blu-ray movies in their current high definition glory through any version of HDMI.
What about lossless audio? You also don’t need HDMI 1.3 for high resolution sound. If your Blu-ray player decodes the lossless formats internally, then the uncompressed sound can be sent from any player equipped with any version of HDMI to any receiver equipped with any version of HDMI. The only circumstance where HDMI 1.3 is necessary for sound is if you want your receiver to do the decoding of the lossless audio. Sure, many of us prefer to use the (generally) better decoders built into receivers rather than use the DVD player’s decoder and Digital to Analogue Converters, but it’s not necessary.
But, there have been problems. The first problem with HDMI was the connector itself. You would think that any HDMI plug would fit into any HDMI input. Alas, this is not the case. Sometimes the plastic surrounding the plug is too big to properly insert it into the input jack. And when it does fit, it sometimes falls out. Although to be fair, this is more of an issue for reviewers who need to constantly swap devices in and out of their equipment racks.
The second problem is HDCP. No, we’re not going to get into the consumer rights debate. We’re talking about compatibility issues. We alluded to DVI incompatibility earlier. The problem is not all DVI equipped displays had HDCP compliance. If this is the case with your display, you will not be able to connect, a DVD player say, using the HDMI output with an HDMI to DVI cable.
The biggest headache with HDCP is the “handshake.” Sounds friendly enough, doesn’t it? Unfortunately the “hand shake” hasn’t always worked properly and it has lead to interoperability problems between HDMI devices.
Some components will work fine with each other, but some won’t. The most maddening situation is when you’re watching a movie and at some point he DVD player and TV need to shake again but this time they get it wrong and you lose the picture.
The HDCP “handshake” has become enough of an issue that the creators of HDMI, Silicon Image, have recently established Simplay Labs. Their aim is to test and certify HDMI products so that compatibility is ensured. Certified products (including cables) carry the SimplayHD logo.
Shopping for HDMI cables
Buying HDMI cables should be much simpler than analogue cables. Any HDMI cable will work with every audio video component, regardless of what version of HDMI the component offers.
With HDMI cables, there is no need for shielding since there is no interference within the cable. A thicker copper core will however allow a longer cable run. For runs longer than 5 meters, a thicker cable is recommended because of inevitable signal attenuation. Signal boosters are available for transmitting a signal over longer distances.
Pay attention to the build quality of HDMI cables. Look for cables that have the HDMI logo on them. This means that the product has been tested at one of the HDMI authorized testing centres and meets the HDMI specification.
One other aspect to consider is the plug itself. While gold plated plugs are generally believed to be better, you should be careful. Although silver is a better conductor, gold platting reduces the likelihood of corrosion. The problem is that poorly made, inexpensive cables use poorly applied, thin coats of gold platting. The platting is susceptible to flaking or scratching off and in the end may provide a poor conduit for the signal.
HDMI is a really great format that offers many benefits over analogue cables. Without doubt most cables running to your AV receiver will eventually be HDMI.
Latest Update (November 2009)
On November 19, 2009, HDMI Licensing announced that it will be abandoning the convention of labeling HDMI cables and consumer electronics components with version numbers. Manufacturers will no longer be allowed to use HDMI specification version numbers in the labeling, packaging or promotion of their products. Instead a transition will be made to market and label HDMI cable products as one of five types (see logos above):
1. Standard HDMI Cable
2. Standard HDMI Cable with Ethernet
3. Standard Automotive HDMI Cable
4. High Speed HDMI Cable
5. High Speed HDMI Cable with Ethernet
In the case of cable products, these restrictions are effective immediately. Non-cable products must comply with the new restrictions by January 1, 2012. Why the change? These new requirements are designed to simplify the product selection process for consumers, enabling them to purchase an appropriate product based on features.
Standard HDMI Cable The Standard HDMI cable is designed to handle most home applications, and is tested to reliably transmit 1080i or 720p video - the HD resolutions that are commonly associated with cable and satellite television, digital broadcast HD, and upscaling DVD players.
Standard HDMI Cable with Ethernet This cable type offers the same baseline performance as the Standard HDMI Cable shown above (720p or 1080i video resolution), plus an additional, dedicated data channel, known as the HDMI Ethernet Channel, for device networking. HDMI Ethernet Channel functionality is only available if both linked devices are HDMI Ethernet Channel-enabled.
Automotive HDMI Cable Designed for internal cabling of vehicles equipped with onboard HD video systems. Tested to a more robust performance standard, and capable of withstanding the unique stresses of the motoring environment such as vibration and temperature extremes.
High Speed HDMI Cable The High Speed HDMI cable is designed and tested to handle video resolutions of 1080p and beyond, including advanced display technologies such as 4K, 3D, and Deep Color. If you are using any of these technologies, or if you are connecting your 1080p display to a 1080p content source, such as a Blu-ray Disc player, this is the recommended cable.
High Speed HDMI Cable with Ethernet This cable type offers the same baseline performance as the High Speed HDMI Cable shown above (1080p video resolution and beyond), plus an additional, dedicated data channel, known as the HDMI Ethernet Channel, for device networking. HDMI Ethernet Channel functionality is only available if both linked devices are HDMI Ethernet Channel-enabled.
To learn how to properly connect your home theatre, please read our Connecting your Home Theatre with the proper cables article.
Home Theater Connection Diagram (courtesy of Ultralink Products)
Click here to view a larger printable version of the diagram.