If believe in prehistory of HDMI in 2002 near the main electronic producers like Sony, Philips, Hitachi, Toshiba was invented an entirely new interface which is called High-Definition Multimedia Interface. This is the world’s first uncompressed digital signal transmitter which transmits both audio and video signals, and it is compatible with DVI interface which transmits only video signal. HDMI was invented for the growing needs of consumers. Obligation of Alliance of was to make HDMI match them. The first version was HDMI version 1.0 which was published in 2002. The newest version 1.3 was released in June 2006. In the new version it has ugraded transfer and better throughout channel. For example, the first version supported bitrate of 4.9 GBps, when the second version supports the entire 10.2 Gbps.
Here is a brief overview of the version history of HDMI:
HDMI 1.0 – 12/2002 Single-cable digital audio/video connection with a maximum bitrate of 4.9 Gbps. Supports up to 165 Megapixels/second of video (1080p @ 60 Hz or UXGA) and 8-channel/192kHz/24-bit audio. HDMI 1.1 – 5/2004 Additional support for DVD Audio content protection HDMI 1.2 – 8/2005 Additional support for Super Audio CDs HDMI Type A connection available for PC sources PC sources can use native RGB color while retaining the option to support YCbCr color. Support for low-voltages sources HDMI 1.3 – 6/2006 Single-cable digital audio/video connection increased to 10.2 Gbps Increased color support, including 30-bit, 36-bit, and 48-bit color depths (RGB or YCbCr) Supports xvYCC color standards Supports automatic audio syncing capability Supports output of Dolby TrueHD and DTS-HD Master Audio streams (audio codec formats used on HD DVDs and Blu-ray Discs) for external decoding by AV receivers. Availability of a new mini connector for devices such as camcorders.
Here is a summary of the major improvements from Version 1.2 to 1.3:
Feature HDMI 1.2 HDMI 1.3
Maximum Data Rate
4.95 Gbps
10.2 Gbps
Maximum Bandwidth
165 MHz
340 MHz
Maximum Resolution
1920×1080 progressive (1080p)
2560×1440 progressive (1440p)
Maximum Color Bit Depth
24 bits
48 bits
Maximum Colors Displayed
16.7 Million
281 Trillion
DTS & Dolby Digital 5.1 Support
Yes
Yes
Dolby TrueHD & DTS-HD Support
No
Yes
Maximum Audio Sample Frequency
(up to 8 channels)
Supported Formats
All primary video formats are currently supported, including PAL, NTSC, ATSC and others. Video resolution goes up to 1440p or 2560×1440 progressive (Blu-ray and HD-DVD currently offer 1080p). Color is 48-bit (over 280 trillion colors) with a refresh rate up to 120 Hz.
Supported audio formats include:
Compressed audio – Dolby Digital, DTS, and so forth.
Multi-Channel Audio – SACD, DVD Audio
Uncompressed (PCM) – Up to 8 channels with 24-bit sampling rates @ 192 kHz
Lossless – Recently added support for Dolby TrueHD and DTS-HD Master Audio
3. Content Protection (HDCP)
HDMI has licensed a built-in copyright protection called High-Bandwidth Digital Content Protection (HDCP), which was created by Intel Corporation for protecting movies and other programming from theft. HDCP is required on HD receivers or DVD/HD-DVD/Blu-ray players and recorders that use HDMI.
HDMI A/V Receivers
If you follow Home Theatre audio at all, you have no doubt heard that the latest thing you just “must have” is an HDMI-enabled A/V receiver. These receivers have HDMI inputs and outputs that provide the following capabilities:
Multi-channel audio and video – With an HDMI receiver, you can run one HDMI cable from video sources (such as an HD disc
player or HDTV cable box) into the receiver input, and another HDMI cable from the receiver output into the HDTV display input. This will allow the video signal to go from the disc player/cable box to the HDTV and the multi-channel audio from the disc player/cable box to the receiver, where it will be output to the speakers. With non-HDMI A/V receivers, you would have to run a separate audio cable(s), such as optical or coaxial digital cable, from the disc player/cable box output to the A/V receiver input. While there might not be much difference in audio quality between HDMI and a separate digital audio cable to most listeners, it does consolidate at least one cable in your system.
Honestly, the benefit of this configuration is not that substantial if you only have one HDMI-based video source in your system. The benefits start to become more substantial as you add more HDMI components in the future, which will allow you to take advantage of….. HDMI switching – Most HDMI receivers currently available contain either 2 or 3 HDMI inputs, which allows you to connect multiple HDMI video sources to the receiver, and only one HDMI cable from the receiver to the HDTV display (some of which only have one HDMI input). You can then switch from one video source to another via the receiver control, as opposed to manually plugging and unplugging HDMI cables from the back of your HDTV or video source(s). This feature will become more important as greater numbers of components become HDMI-based. Analog- to-digital video (up)conversion and deinterlacing – Early releases of HDMI receivers kept digital and analog video signals separate, which would require analog A/V connections from the receiver to the HDTV. However, many current receivers convert incoming analog A/V signals (such as component or S-video), so all signals are output through a single HDMI cable. In addition to conversion, some receivers also deinterlace video signals (from 480i to 480p) – this can be a crucial feature, as some older HDTVs do not accept 480i signals from an HDMI connection. Some of the newer receivers even upconvert all 480i signals to 720p, 1080i, or 1080p, which should improve the appearance of older video sources when displayed on a newer HDTV.
HD-DVD/Blu-Ray Compatibility
Going forward, one very important aspect of HDMI is that HD-DVD and Blu-ray players will only output at their full resolution of 1080p using the HDMI output. This is a result of the movie industry’s increasing concern over copyright protection; unlike other A/V cable standards, industry groups and governmental regulations require the security of HDCP when using an HDMI connection. If you use any other connection, like component video, the signal will be downgraded so the image quality will be DVD-quality or worse.
The increased bandwidth capabilities of HDMI 1.3 will accommodate emerging technologies that will be utilized by HD-DVD/Blu-ray. This includes an increased video color depth standard called “deep color”, which will display up to 69 billon colors (30-36 bit color depth). HDMI 1.2 could only display 16.7 million colors (24 bit color depth). In addition, HDMI 1.3 will accommodate the next generation home theater sound formats of Dolby TrueHD and DTS HD Master Audio, which use up to 8 channels of 24-bit, 96 kHz lossless audio at up to 18 Mbps. All non-1.3 receivers will playback the legacy DTS and Dolby Digital formats.
While these improved capabilities will certainly improve the home-theater experience eventually, one area where HDMI does not have a solution is transmitting data for recording purposes. Data passed through HDMI is uncompressed, and HDCP’s primary function is to protect uncompressed data from being copied. Therefore, there is currently no way to record any HDCP protected data via HDMI. So while you should be able to record and backup unprotected video content such as home-movies, you will not be able to record copyrighted television or movie content. It will be interesting to see how (or if) this issue will be addressed in the future.
Conclusion
This is an interesting time in home theater technology. There is an 1080p video format war with HD-DVD and Blu-Ray, as well as the added confusion of a new A/V cable format in HDMI. In addition, HDMI continues to update itself with new version releases.
With the release of HDMI 1.3, there are many factors to consider if you are attempting to purchase new A/V equipment. HDMI receivers have not been on the market very long, and have already gone through significant changes in capabilities. HDMI 1.3 is a significant upgrade from 1.2, so it would be preferable to hold off, if you can, and purchase components that will support this standard – especially since both HD-DVD and Blu-Ray will utilize the improved capabilities. However, HDMI 1.3 receivers may not be available until mid-2007, and who knows what the price range will be when they are initially released. Also, some cool features of HDMI receivers, like HDMI switching and video upconversion, are available in current HDMI receivers.
HDTV displays are also going to be offered with the HDMI 1.3 standard, with the first round of displays being announced for release in early 2007. These units will take advantage of increased color depth, as well as other improvements such as audio-sync issues and Consumer Electronics Control, etc. The bottom line is to carefully check the features of each component you intend to purchase, and try and match them to your current needs – and perhaps more importantly, your future requirements too.
Tom’s Hardware
