HDMI cable made a difference in picture quality??

I am really fasinated by the responses I have seen here. Some members claim to see sharper or brighter pictures. Can somebody explain to me how is it possible with digital? I mean, how can cables transmitting digital information apply filter to make picture less or more sharp, or darker or brighter?

If you freeze frame, it would cause the digital source to output the exact same data per each frame per second. So if there is distortion caused by cable not up to specification, radom noise would be introduced in the form of digital artifacts. They would be so obvious as they would not look like as if there is a digital filter applied to the picture to make it look faded or details missing. Plus, since the data is constant, any artifact would not appear still, as the data stream is constant, any noise would be randomly injected.

Also, HDMI data is checksumed, see HDMI specification:

www.hdmi.org/pdf/HDMISpecInformationalVersion.pdf

Hifisoundguy, it would not be likely for digital artifacts to show up as faded or missing details.

For analog tranmission, yes, since the output of analog is a direct product of the signal being transmitted and if cable is suspect, then result picture/sound can appear as if there were filter applied to make the picture look distorted, faded, etc.

But for digital, the analog is first encoded to digital and then the digital bits are converted to analog to transmit the signal, then the analog signal gets picked up and converted back to digital and finally to analog again. So any noise in the transmission would not appear uniform such as that the noise introduced fades the picture.

Think about back in the days of analog TV signal, if you don't have clear signal, your picture looks distorted, but at least in a recongnizable way. But if you have an HD antaena to pick up digital signal, you either get a picture or you don't. Or if it locks on a weak signal, you can see the digital artifacts very clearly (blocks of green or bad pixels).