Quote:
Originally Posted by
mjugen 
Is it possible that hdmi cable make picture better, my logic and brain tells me no..........?
TBH, the reason I asked dbturbo2 to elaborate is because I am skeptical of his claim, and I want to see if there are acutally observable differences in photos.
When an HDMI cable is flaky, the only visible effects you should see are white pixel snow or sparkles, or a complete loss of picture. And in fact, the white pixels are just loss of picture on the individual pixel level.
In order for the effects that dbturbo2 talks about to occur, the faulty cable would actually have to be intelligently "editing" all of the pixels in the image in a consistent fashion. And by that I mean like the cable is Photoshopping the image. In order for TV's and projectors to manipulate a characteristic like contrast, they rely on video processing chips. So if you're seeing an image that seems to have less contrast, that has to be algorithmically produced, and would not result from the kind of random bit errors a flaky cable would cause. Likewise, while a poor quality physical optical element like a lens or prism can result in haziness, in the digital world, you would need an algorithm to produce an effect that you might call "haziness". Think about it, in Photoshop, to blur an image, you can't just throw random bit flips into the picture. You have to use a blur algorithm that a human being designed to simulate an analog effect (the blur) via digital manipulations.
The bottom line is that errors in the analog domain (poor contrast, bad focus) are fundamentally different from errors in the digital domain (flipped or missing bits). The possibility of digital errors amounting to a recognizable analog error is like a monkey banging out Shakespeare on a typewriter. It might seem strange to call a fuzzy picture Shakespeare, but go try to write a digital blur algorithm and you'll see it's not something that would happen by chance.
Here's another way to think about it. When you listen to music that's being streamed over a network, does a flaky ethernet cable make the audio sound muddier, or mess with the treble and bass, or affect stereo separation? No. It can't, because the ethernet cable would have to know how to manipulate audio in order for that to occur. If there's a problem with the network cable, the audio stream might just stop. And the reason you don't hear hiccups due to bit or packet loss is because the TCP/IP protocol has retransmit and guaranteed in-order delivery. HDMI TMDS does not have retransmit and guaranteed delivery, which is why you get white sparkles. If it did, the only problem you'd ever see from a bad cable is complete loss of picture.
To the extent that people swear they see a difference between HDMI cables, I would frankly ascribe that to the placebo effect. I'd be fascinated to see evidence to the contrary though.
Edited by Xank - 3/1/13 at 4:15pm
