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Before discussing the benefits of High Definition Multimedia Interface (HDMI) switching over a direct connection, it is important to understand the benefits of HDMI. This technology first arrived on scene in early 2006. It was used in HDTV camcorders and digital still cameras. The HDMI technology helps producers of digital format videos and audio protect their products and allows for transfer of data at high rates.
HDMI is the Digital Rights Management (DRM) answer to the common analog standards of coaxial cable, S-video, component video, composite video and SCART. It also covers the digital standard of Digital Video Interface (DVI.) The versatility, ability to handle many different formats, makes the High Definition Multimedia Interface attractive to high end video users. It can handle any TV or PC video input, including high definition video. Since MPEG movie data streams are passed off to a decoder in HDMI, it is independent of the standards that limit DVI. This data is encoded into Transition Minimized Differential Signaling (TMDS) and then transmits it digitally over the HDMI.
HDMI also supports 8-channel uncompressed digital audio. It is backward-compatible with DVI that is commonly found on computer monitors and graphics cards. As the technology continues to grow the bandwidth sample rates will increase as well.
So, if HDMI supports all of these formats then everything must be perfect, right? Not quite. Because HDMI is a DRM technology the sending and receiveing units must be connected by the recognized HDMI. When switching from one source to another with a direct connection the change must be made manually. The cable handling the data must be changed in order to deliver the information.
Most modern HDTVs can handle a direct HDMI connection from a DVD. To switch to another input, such as a laptop, or audio inputs, the cable input must be changed. This might require changing the cable or, with the old switching units, manually flipping a switch on the reciever. This requires getting up off the couch and making the switch. In today’s world of convenience and automatic switching recievers nobody wants the hassle.
An automatic switching reciever with multiple ports for incoming HDMI and one output (to an HDTV or projector) allows various sources to be plugged in and, using a remote, switched back and forth without every leaving the couch. The need for manually switching between components is eliminated. As the technology moves forward the switching has become truly automatic and switching occurs at the reciever without the need for user input, such as when one component is turned on or off. Convenience is a major benefit of switching at the reciever.
When a direct connection between the DVD and TV is in place the other components are limited. The one HDMI port on the television is used up and other feeds are no longer available. Cable with high definition feeds can not be plugged in. The limitations make that HDTV very one dimensional in its uses. A reciever with multiple inputs also allows components with different formats to feed through to the reciever and on to the TV or projector. Audio, video, computer, and gaming consoles can all be plugged in to a reciever and sent to the receiving unit through the single output. This eliminates the need for plugging in and unplugging components as they are needed, or manually switching between input sources. This also reduces the number of remote controls needed. One remote can control and switch between the various components.
The bacward-compatible nature also allows the HDMI and DVI inputs and outputs to work together without having to make a switch. Since DVI can manage an HDMI monitor, without the audio and remote control features, this source could could allow for multiple feeds into the HDTV or computer monitor, even with DVI inputs. The HDMI can control the DVI reciever as well. If the receiving unit (televisions or computer monitor) has a DVI input and the sending units are HDMI, the reciever can act as an adapter. This changing of formats does require some adapters and appropriate matches on each end but can be accomplished with switching at the reciever. Direct connections would not be available.
Convenience, not having to get off the couch, when switching is one of the major benefits associated with HDMI switching at a reciever, when compared to direct connections between the sources and TV. The ability to connect multiple input sources, possibly of different formats, is another benefit. When looking at various recievers the real question is not whether it is needed, but how many ports for input are needed.