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The inevitable rule in the information age is: "if it can be digitized,
it will."
The transition from analog to digital in the video world has been quick
and a key enabler of this has been HDMI, High Definition Multimedia
Interface. Virtually all HD equipment utilizes HDMI to transport
audio/video from the sources to the display. The original rendition of
HDMI, HDMI 1.0 was released back in 2002 and has been the de facto
standard for HD Video transmission. As the digital revolution has
continued, HDMI has also evolved from 1.0, 1.1, 1.2 and mostly recently
HDMI 1.3.
Revision History:
HDMI 1.0 -Single-cable digital audio/video connection with a
maximum bit rate of 4.9 Gbps. Supports up to 165Mpixels/s video
(1080p60 Hz or UXGA) and 8-channel/192 kHz/24-bit audio.
HDMI 1.1 - Added support for DVD audio
HDMI 1.2 -Added support for One Bit Audio, used on Super Audio
CDs, up to 8 channels. Ability for PC sources to use native RGB
color-space while retaining the option to support the YCbCr CE color
space.
HDMI 1.3- Increases single-link bandwidth to 340 MHz (10.2 Gbps)
-Optionally supports 30-bit, 36-bit, and 48-bit xvYCC with Deep Color
or over one billion colors, up from 24-bit sRGB or YCbCr in previous
versions.
-Incorporates automatic audio syncing (lip sync) capability.
-Supports output of Dolby TrueHD and DTS-HD Master Audio streams for
external decoding by AV receivers.
-Availability of a new mini connector for devices such as camcorders.
Do I need HDMI 1.3:
You will still get incredible HD picture quality with HDMI 1.1 and HDMI
1.2. HDMI 1.3 is backwards compatible with previous versions of HDMI.
Getting HDMI 1.3 display and HDMI sources will enable you to take
advantage of the extra feature enhancements available. If you are in
the market for a new HDTV, then it would be advisable to get one with
HDMI 1.3 support. However, you should look for the specific features
that are supported.
HDMI 1.3 - what is different:
On the physical layer level, all HDMI versions utilize Transmission
Minimized Differential Signaling, TMDS and the physical connector looks
identical. The major enhancements of HDMI 1.3 are:
Expanded Data Rate Support
HDMI 1.2 supports aggregate data rate of 4.95 Gbps.
In order to ensure that HDMI is the connectivity of the future, HDMI
1.3 has provisions to eventually double the bandwidth from 4.95 Gbps to
10.2 Gbps. For comparative purpose, USB 2.0 has a maximum data transfer
rate of 480 Mbps, 1/20 of the data rate of HDMI 1.3.
Although, HDMI 1.3 has provision for up to 10.2Gbps, the transition
will be gradual with the first devices available to achieve 6.75Gbps
initially.
Deeper Color and higher resolution
The increased bandwidth in HDMI 1.3 enables higher display resolutions
beyond the typical 1920x1080P resolution and improved color depth. For
example, HDMI 1.2 allows 8 bits/ pixel to be allocated for color
information. In version 1.3, HDMI has provisions to support 10, 12 and
16 bit color/ pixel thus allowing for even improvement in picture
quality.
Lip Synch Correction
The modern HDTV performs complex digital processing to the incoming
video signal such as de-interlacing, format conversion, noise reduction
and etc. The digital video processing takes finite time to execute and
must be synchronized with the audio portion of the incoming signal to
ensure that both video and audio are synchronized and no delay is
perceived. Most HDTV have compensation to ensure that the audio and
video are properly synchronized However, many consumers will likely
process the audio separately in a surround sound system. HDMI 1.3's lip
synch feature allows the audio and video signal to be synchronized to
external HDMI devices.
Mini Connector
HDMI 1.3 has also added an optional mini HDMI connectors so handheld HD
video devices such as HD video cameras can also utilize HDMI for HD
connectivity.
What is still the same
HDMI 1.3 is fully backwards compatible with previous versions of HDMI.
So if your display supports 1.2 and your source is 1.3 capable. The
source and display will arbitrate for the best available format. HDCP,
although not required by HDMI 1.3, still enables HDCP to be implemented
over the HDMI interface.
About the Author
Jeffrey Su is product development manager at www.octavainc.com.
Jeffrey is a graduate of the Georgia Institute of Technology (BSEE,
MSEE) and has over 10 years of experience in CATV systems, RF, and
microwave designs. He may be reached at
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