High-Definition Multimedia Interface (HDMI)
HDMI is a one-cable, copy-protected way to connect a high-definition AV component to another component. HDMI can pass 1080p video and HD audio (DTS Master Audio and or Dolby True HD) on one cable. This content can copy-protected between, for example, a Blu-ray player and an AV receiver or an AV receiver and a video display such as a plasma, an LCD or a front projector.
HDMI cables do not lock and therefore can be easily pulled out. HDMI takes up a lot less space on a receiver or an AV preamp than component video (analog), which has three connectors, each one larger than an HDMI connector.
HDMI as a format uses HDCP copy protection, which is a relatively robust encryption.However, this encryption has been broken. It is not common for mainstream consumers to copy content that is copy-protected from Blu-ray to other media.
HDCP copy protection is needed for the digital transfer of the highest-resolution 1080p digital video (and high-resolution audio like Dolby TrueHD and DTS-HD Master Audio) from players, including Blu-ray machines, AV preamps and receivers, via an HDMI cable.
HDCP copy protection is the main culprit for HDMI connectivity or "handshake" issues that frustrate the home theater enthusiast and/or AV installer. Without HDCP, Hollywood movie studios will not release content in master quality versions.
HDMI Handshake
Nothing pisses off consumers and home theater installers more than the dreaded "handshake" issues found with HDMI. The overall design of HDMI has been a nightmare that should have resulted in some sort of public executions because of the frequent software/firmware changes, the lack of communication between the developers and the AV companies and beyond.
In theory, HDMI should provide flawless, one-cable connection for all AV equipment that sends HD audio and video on affordable and high-performance cables. It should be so easy and reliable that every consumer and retailer/installer gladly accepts the fact that content sent via HDMI is more often than not copy-protected. In reality, AV equipment varies in versions of HDMI compatibility, so that an HDMI 1.1 first-generation Blu-ray player could be connected to an HDMI version 1.2 AV receiver and then plugged into a brand spanking new HDMI 1.4 LCD or plasma HDTV. On first try, the system might work, but because of these copy-protection issues, you might find later that there are intermittent problems (or none at all). These are due to handshake issues.
Note: non-HDCP copy-protected components, like DVD-Video players with HDMI or satellite receivers, rarely suffer from HDMI handshake issues. Newer copy-protected components are also better than the highly flawed first-generation players.
Solutions to HDMI "Handshake" Issues for Home Theater Systems
1. Reboot the gear. Amazingly, this works. I hate to sound like the Indian guy at the call center for your cable company, but your home theater system is acting more and more like a computer, yet it doesn't get restarted as often. Sometimes a simple power cycle will solve your problems.
2. Update the firmware. Download new firmware for your gear, as HDMI compatibility issues keep AV manufacturers up late at night, cooking up solutions. One spin of a DVD you burned from your computer can make things work perfectly all of a sudden.
3. Not all cables are created equal. For long runs (longer than a meter or two), use only high-quality HDMI cables. Some connect better than others.
4. Keep your system simple. Adding switchers and extra junk into your HDMI-based system makes things more likely to fail. Run your audio and video via HDMI from your Blu-ray and other sources into HDMI inputs on your receiver, and then from your receiver to your video display.
5. If you have a LONG run of HDMI cable between your receiver and your video display, use a fiber optic cable. It's the best solution for performance and bandwidth. It also works is probably the best solution for some connectivity issues.
HDMI has been through many format upgrades in its first few years on the market.
HDMI 1.0
HDMI 1.0 was the first version of the much-ballyhooed HDMI one-cable, copy-protected connection system that have changed the way HD content gets from AV sources en route to video display and audio playback systems. HDMI 1.0's specifications boast a maximum TMDS bandwidth of 4.9 Gigabits. It supports up to 3.96 Gigabits of video bandwidth (1080p video at 60 Hz or UXGA) and eight-channel LPCM/192 kHz-24-bit audio.
HDMI 1.1
HDMI 1.1 version of HDMI was released on May 20, 2004. This added the ability to provide support for the now-dead DVD-Audio format.
HDMI 1.2
The HDMI 1.2 version of HDMI, released on August 8, 2005, added the following to HDMI functionality:
• Support for DSD or one-bit SACD sources
• Type A connectors for computer (PC) sources
• Support for low-voltage devices
• Synchronization of home theater-oriented video with computer screens.
HDMI 1.2a
The 1.2a version of HDMI, released on December 14, 2005, added functionality for:
• Full Consumer Electronics Control (CEC) features and tests.
HDMI 1.3
The HDMI 1.3 version of HDMI, released on June 22, 2006, added the following to functionality:
• Increased bandwidth to 340 MHz
• Supports Deep Color (optional), with 30-bit, 36-bit and 48-bit color, much increased over past standards
• Audio synch
• Optionally supports Dolby True HD and DTS Master Audio decoding in external receivers and AV preamps
• Approved use of type C "mini" connector
HDMI 1.3a
The HDMI 1.3a version of HDMI, released on November 10, 2006, added the following to HDMI functionality:
• Modifications to improve connectivity of the mini-connector (type c)
• Source Termination guidance
• CEC capacitance limits modified
• SRGB video range clarified
• Audio commands added
• Compliance test specification
HDMI 1.3b
The HDMI 1.3b version of HDMI, released on March 26, 2007, is much hyped, but only adds testing to the HDMI standard and, from a consumer standpoint, is basically the same connection as HDMI 1.3a.
HDMI 1.4
HDMI 1.4 is an advancement from HDMI 1.3b which was an advancement from HDMI 1.2 which was an advancement... you get the idea.
The 1.4 version of the HDMI spec added higher potential resolutions, HDMI Ethernet Channel (HEC), Audio Return Channel, and 3D Over HDMI. The latter is the most useful right now, as 3D is getting an extreme marketing push from all angles. HDMI 1.4 supports several 3D formats.
You don't need to upgrade your HDMI cables to take advantage of the new features (with the exception of HEC). If you're interested in 3D, though, you will need a 3D capable TV and 3D capable Blu-ray player (or the PS3)..
For even more information, check out the Wikipedia article or visit HDMI.org.
Long runs over HDMI cables can be problematic. It is important to test any cable before running it through walls. Certain companies make high-quality optical cables with converters to HDMI on either end, allowing for long, error-free runs.
HDMI Switchers
In the early days of HDMI, nearly all receivers had no more than one (if any at all) HDMI input. It became increasingly complex to control an HDMI system with a Blu-ray player, an HD DVD player and an HD DVR. These system complexities gave birth to the HDMI switcher component. The first units were 2x1 (meaning two inputs and one output) and quickly grew to be as large as 6x2 at the consumer level and far larger on the commercial side.
Today, HDMI switchers are more for older systems, as they do not easily (if at all) pass the HD audio that comes on HDMI 1.3. If you desire both HD video and high-definition audio (DTS Master Audio and or Dolby True HD), which both require the more current HDMI connections, you are better off upgrading your AV preamp or receiver than using an HDMI switcher. If you have an older system and are willing to bypass the HD audio options on Blu-ray for lossy surround sound formats like DTS and or Dolby Digital, you can use an HDMI switcher to add inputs and flexibility to your system.
