With streaming data are "premium" cables better than generic?

Question

I understand that with data transfer from computer to an external hard drive via USB, the data on the external will be exactly the same as the original data, barring any hard drive malfunction. So if I were to move a .jpg from one hard drive to another, a billion times, the .jpg file would be identical to the original. I understand that packets of data can be lost during the transfer, but the computer detects the lost packets and re-sends them, thus preserving file integrity. This being said, if a cable was of very low quality, could the overall speed of a file transfer be affected due to the need to resend lost packets?

Also, in an HD TV setup, doesn't the HD signal simply "stream" to the TV? I thought that with TV the data packets that are lost aren't re-sent. Thus wouldn't a shoddy HDMI cable produce a slightly inferior picture than a premium cable?

I keep hearing that HDMI is digital and there is no loss of data, if that is the case, since HDMI streams at up to 6Gbps, couldn't massive packet loss create a bottleneck in the system, forcing the television to display an incomplete, or less than perfect picture?

Answer 1

Your questions are sort of assuming that the "premium" cables actually do perform better than the basic ones. In almost all cases this is not true.



Expensive cables might have fancier connectors and a thicker jacket, but that's about it.



You are correct that with HDMI (or DVI for that matter) lost or corrupted packets aren't re-sent. There literally isn't time. There is error detection in these protocols but no provision for correction. TV or monitor can detect the bad packets and ignore them but there's no erorr correction in the data that's sent, nor is there any sort of response back to the sender to ask for a retransmission.



Later: To the person below - I don't think so. If you'll web search for the terms "error correction" and HDMI you'll find a huge number of sites stating that there is none, at least for the video.



The video in DVI/HDMI is sent via TDMS, and the DVI spec clearly states



"There is no requirement for error handling over the T.M.D.S. link"



(page 31, http://www.ddwg.org/lib/dvi_10.pdf )



and that is the only place the word "error" appears in the entire document.



TMDS as used by DVI/HDMI does use 8-into-10 encoding (similar to CD-DA's eight-to-fourteen modulation) for the video data, and this permits error detection, but is not sufficient redundancy for error correction.



There are ECC bits in HDMI in the "data island period" but these do not apply to the video, only to the data (such as audio) within the data island period.



If you still disagree I would appreciate seeing a reference.

Answer 2

Yes to most of your questions....



Use ANY HDMI 1.3a cable and you'll be guaranteed the highest data transfer whether it's a $20 cable or a $120 cable



And I wouldn't throw $100 out the door for a cable that doesn't do anything MORE than the $20 HDMI 1.3a cable can.



You see, it's the HDMI 1.3 STANDARD that guarantees the best throughput...you can't stamp it with the "1.3a" seal of approval unless it passes their testing...



So the word cheap doesn't apply here...Best price or Worst price does...



Oh, and to the guy just above me....WRONG! Wrong wrong wrong!!



There IS ERROR CORRECTION done with the HDMI signal !!

It detects lost packets, and can rebuild them ! You do see pixellation when the AMOUNT of lost packets is so High the TV set can only "Rough In" the Block of lost information, but it error corrects nonetheless....

Answer 3

Quite honestly, I've heard many different things.



Generally for HDMI there are two camps. One says that since its digital it either sends it or it doesn't, meaning the cable doesn't matter. The other sees it differently.



In my opinion though, a cable is only as strong as its weakest link. That USB cable, no matter how good, you should remember that the USB port is connected to a USB header by copper wires. If the copper beaks, that cable loses all effectiveness.



Same with HDMI. Really, I would buy cables as long as they don't look terrible and are cheap. A.K.A most cable at monoprice.