HDMI (High-Definition Multimedia Interface) is the current de-facto connectivity for most AV equipment.  In the old days, when we were still using analog component or coaxial cables, manufacturers came up with various ways to improve the cables. In the more expensive cables, you will find gold plated connectors, or EM/RF shielding on the cabling. Coupled with fancy marketing and packaging, the difference in pricing between a plain vanilla cable and a high-end cable could be 10-20 folds. But does all these optimization apply for HDMI, which utilizes digital signals?

As we all know, digital signaling uses a combination of  zeros(0) and ones (1) for transmission, so in theory the signal transmitted should either work or fail; there is no “in-between”. Analog signals uses sine-waves for transmission, so if there are external interference, it will result in image degradation (by augmenting the sine-wave in transmission).  For digital signalling, failed transmission should result in a failed pixel display (appearing like sparkles on screen). Some cables are also marketed as Ultra-High bandwidth, but in actual fact, the HDMI 1.3 (and the upcoming v1.4) specifications states that cables should only require to meet the 340MHz (10.2Gbps) bandwidth requirements. Below is a breakdown on the amount of bandwidth require that is required for uncompressed Full HD 1920×1080 video. This also takes into account for the vertical and horizontal blanking pulse to denote a new frame.

HDMI bit-rate = (horzPixels + hBlanking) x (vertPixels + vBlanking) x bitsPerPixel x frameRate x 10/8 (for TDMS encoding) x 3

Full HD 1920×1080, 60fps, 8-bit color per channel (24bit RGB) = [ (1920+280) x (1080+45) x 24-bit color x 60fps x 10/8 (extra 2-bit for TDMS enconding) x= 4.45Gbps

So in theory, any cable that meets the HDMI 1.3 specifications should be more than ample to support the bandwidth required. There is no  need for additional bandwidth at all, at least at this point.

Several tech sites had also performed testing with generic HDMI cables vs expensive Monster cables, and using specialized software to capture the transmitted output on the end display . The results are a victory for those of us who does not buy into marketing gimmicks and actually had some common sense. The output is 100 per cent identical, whether you are spending $10 or $100 on a cable.  HDMI guarantees you a pristine image – how good the image is comes down to the quality of your screen, and your perception of how it looks. People that purchase expensive cables might fall into the placebo effect, as personal perception is hardly measurable.

From my research, i would say it is safe to say that any properly manufactured cables with no loose cable or broken heads should work flawlessly for most home users that do not require HDMI cabling more than 4 meters . As cable length increases, the quality of the cabling becomes more prominent as the signal needs to travel further, and is more susceptible  to signal degradation issues. Below is a breakdown from mint.com of what i have discussed above in pictorial form.

Question is: are you going to be a douch nozzle or feed the children?

HDMI Truth