rjhseven said:
Do you guys think the HR24 would give me a better PQ?
Speaking as a broadcast Engineer who works closely with digital signals daily, I am absolutely certain it would not. Digital signals, unlike analog signals, are totally and completely impervious to a degradation of PQ. They are not impervious to transmission and reception problems, which can be plagued by macroblocking and stuttering, but this is a completely different issue than PQ. Even if the picture is macroblocking or stuttering, the actual quality of the images, although not displayed properly by the transmission/reception issue as far as the integrity of the signal, is identical to the quality when this is not happening. Its a fine distinction, not always easy to understand.
The PQ is represented in its entirety by a set of binary coefficients once digitized. The only thing that can change that information would be a mathematical operation done on purpose, and that never happens inside a DVR or STB (except when converted to analog for component or composite outputs). From the point that final compression is done at the uplink, the PQ is locked and identical for everyone, for all receivers, for all DVRs. Even DVRs from completely different companies (Tivo and DTV, for example) when receiving the same signal (an OTA station, for example) will produce absolutely identical PQ.
The reason is that no matter what happens to a digital transmission, nothing can reach in and change the numbers of those coefficients, which means nothing can degrade or improve PQ. It is fixed at the uplink, and can't be changed, because those numbers can't be changed, and aren't changed, until after the signal exits the DVR (assuming HDMI) and is inside your TV set.
PQ varies a lot from TV to TV, but that is because the numbers are indeed changed, sometimes by digital processing (but rarely) and always by a conversion back to analog, which happens very early on inside virtually every FP HDTV set. Most HDMI receiver chips have a digital to analog converter chip directly on board expressly for this purpose.
But since the digital information is encapsulated from before the uplink, through the DVR, and all the way into the belly of the TV, no, the PQ is locked in the identical state it was in before it ever leaves the uplink, and your DVR has no opportunity to degrade the signal.
DVRs fail, but digital circuitry fails differently than analog circuitry (which can degrade PQ) and does not ever affect PQ. This is one of the two big reasons why digital is used in the first place, the second being it compresses very easily while analog does not hardly compress at all.
If you have a PQ issue, look elsewhere than the DVR; beyond that point in the signal chain. For any device that handles a digital signal totally within the digital domain, and a DVR is a prime example, PQ transits through that device completely transparently. This includes MPEG decoding, which since it is always an exact reverse of the original encoding, is done exactly the same way in all DVRs, even if the decoding chips come from different companies on opposite sides of the planet. A newer DVR may have a cheaper, better decoder capable of more than the older DVR, but it must decode exactly oppositely of how the signal was encoded, so does that exactly the same.
