Background:
As the Hdtv shop continues to heat up, consumers are in need of being educated on the newest technology. One of the terms that you, the consumer, will absolutely run into while selecting a Hdtv set is: Hdmi. For most this is an unfamiliar term and we will account for the details of Hdmi in this narrative so you, the consumer, is armed with the allowable knowledge to make absorbing purchasing decisions.
Hdmi Tv
What is Hdmi: Hdmi is an acronym for High Definition Multi-Media Interface. The Hdmi specification (now at 1.2) was created by some of the largest consumer electronics manufacturers in the world: Hitachi, Matsushita, Philips, Silicon Image, Sony, Thomson, and Toshiba. Hdmi is the newest digital Hdtv interconnection standard. The noted differences in the middle of Hdmi and the earlier Hdtv interconnects standards (component video, and Dvi) are:
-Hdmi is all digital unlike analog component video cables
-Hdmi supports multi-channel audio in increasing to digital video. (Dvi only supports digital video)
- Hdmi is more covenant in size and carries both audio and video signals therefore eliminate cable clutter.
-Hdmi incorporates content security called Hdcp ( high definition content protection)
What does a Hdmi connector look like: Hdmi looks similar to a Usb cable. The covenant size and high integration (carries both audio and video) makes the Hdtv premise perceive truly "plug and play."
Why should I use Hdmi:
-Hdmi is all digital, so photo quality is "perfect" from source to display
-Hdmi is both a digital audio and video connection. This will minimize cabling in your system
-Hdmi is rapidly becoming the de facto approved for Hdtv connections.
How does Hdmi converyance the digital video: The video part of Hdmi is carried by 3 detach differential pairs. Each pair transports 1 of 3 uncompressed native digital R,G, B signals from source ( dvd player, set top box) to the sink ( Hdtv display). A unique protocol, T.M.D.S.( transmission minimized differential signaling), is used to converyance the digital data. Each pixel is represented by 24 bits ( 8 bits each for each of the original colors). The T.M.D.S. Protocol then "calculates" and stuffs 2 extra bits to the video data stream in order to originate a digital stream with minimum transitions ( lower Emi, lower interference) and also minimize long strings of '1' and '0' which can cause detection errors.
A fourth differential pair, called the Tmds clock provides the pixel clock for timing the data stream. The maximum Tmds single link pixel clock rate is 165 Mhz.
What is the data rate of a single link Hdmi connection: The maximum pixel clock rate is 165Mhz and each of the 3 Tmds video streams carries 10 bits. Therefore the composition data rate is 3 x 10 x 165Mhz = 4.96Gbps.
How many pins are included in the Hdmi connector: There are 19 personel pins in the Hdmi connector. There are 3 pairs of Tmds signals which carry all the digital audio and video signals.
How is the digital Audio signal transported: The multi-channel audio is time multiplexed into the Tmds data streams. Audio is much lower data rate (192kbps) and the extra time is used to demux the audio signals.
What is Hdcp: Hdcp is an acronym for High-Bandwidth Digital content Protection. Hdcp is an encryption formula industrialized by Intel in order to control unauthorized copying of digital media. The encryption is carried out in the Hdmi transmitter found in the "source" ( dvd player, set top box) and decryption is carried out by the Hdmi receiver ( the Hdtv display). The inexpressive keys for encryption are exchanged in the middle of the source and display over an I2C bus ( pins 15 and 16).
Is Hdmi compatible with Dvi: Dvi is the predecessor to Hdmi. Hdmi and Dvi are same as far as video is concerned. Therefore, video backward compatibility exists. However, Dvi will not sustain digital audio. For example, if you have an older Dvi relationship on your source and a Hdmi connector on your display, a Hdmi to Dvi cable is all that is needed in order to view the video. A detach audio cable ( Toslink or Spdif) will be needed to carry the digital audio.
What formats will Hdmi support: Hdmi is high speed digital relationship and will sustain resolutions of 480i, 480P, 720i, 720 P, 1080i and in the future,1080P.
Conclusion:
Hdtv technology is changing rapidly. Hd connections such as Hdmi will come to be the de facto approved in Hdtv connections. We have outlined the important features of Hdmi, so the consumer is well informed and ready to make absorbing purchasing decisions.
Hdmi: Guide to Hdtv connection of the future
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