All digital is not always good

R

rob

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#1
There is a belief that digital is synonym with quality. Manufacturers spread the misconception and the media happily relayed it. I am not going to dwell over the concept of converting an analog signal into a digital one, as I am sure that we are all acquainted enough with all its aspects. Sure, a digital signal has the advantage of not degrading over many transfers, but a digital signal can often we less accurate than the original analog. Asia and its video-cd is a prime example. Yes, it's digital. No, it's not a good image (barely VHS!). Look at MP3. Some people claim that the average listener will not notice the difference with regular CD-sampling quality. Well, I am not sure about that. Why then are so many people waiting for high definition CDs?

This brings me to digital TV. Is it me or is the video quality of a movie broadcasted, let's say on SKY, not as "good" as the same movie when I watch it on my DVD player? I see whole blocks of image freezing on my TV! Often it's just a dark background, but sometimes it's a more lighter and busier portion of image. Say, a tree with it's tiny leafs, a curtain on a wall, a green lawn... This is even more noticeable on a large TV or a projector in my case.

Many viewers may not notice it. Well, there are still a lot of people who have a 15-inch TV with washed-out colors... But for those who have a trained eye and are used to good DVDs, it can sometimes be annoying.

What do you think?

Rob
 

2old4this

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#2
(I've moved the thread here from the Sky Digital forum since the subject matter is not Sky-related)

Digital trasnmission is more robust (more tolerant of transmission errors) but the problem is providers try to squeeze in too many channels into a particular digital frequency/transponder. The blocking artefacts arise even under ideal transmission/reception conditions because the amount of information transmitted exceeds the available "bandwidth", so that much more compression is needed.
Analogue transmissions under ideal conditions don't suffer such indignities but then you only get max 2 such channels per frequency (H & V) instead of up to 20 under digital.

So the artefacts are NOT due to the technology, but to the providers wishing to cram in as many channels as possible into their expensive transponder space...

The dishonest aspect is that providers advertise digital TV as being both crystal-clear AND offering many more channels. In reality, there is a trade off.

If you want an example of a consistently apalling digital signal watch watch BBC-Prime...

2old
 
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