HCPC and Prog Scan!

[Canary_Jules]

I admit it! I'm confused! I've been looking into whether I should buy R1 DVDs or carry on with R2. Are all R1 DVDs prog scan? And does it make any difference with an HCPC? I heard somewhere that PJs convert non-prog scan signals into prog scan any way. Is this true?

I understand that Pal Progressive DVDs are not yet really available, so the bottom line is will prog scan R1 discs give me any advantages in terms of picture quality?

Totally confused - and don't like it!



Jules

 

[KraGorn]

DVDs are interlaced, all of them, no matter what region or TV standard, otherwise they'd not play on normal CRT devices like TVs.

It's the DVD player or some other processor or the display device itself that de-interlaces them, a process known as 'progressive scan'. A PC normally outputs a non-interlaced signal, though you can force interlaced for some resolutions if you really want to, therefore an HCPC is a 'progressive scan' processor in this respect.

Now, in the light of that, does it all make sense?

 

[Canary_Jules]

That certainly helps. So is it my Theatertek software that deinterlaces the DVD signal? And is that therefore producing by default a prog scan signal on both my R1 and R2 DVDs?

 

[KraGorn]

I just edited my post a little, may be a bit clearer.

You're correct, TT does the de-interlacing .. and indeed that's one of the reasons TT gives generally the best results due to the decoder it uses, which in turn gives a better PQ using a Radeon card because the ATIs have on-board hardware support for MPEG decoding.

Of course, if you set the PC to output an interlaced signal then you'll defeat much of the good work, but I've never seen an application which required an interlaced signal from the PC.

 

[Magsy]

Urm maybe I've been mislead all along, but arent all film based DVD progessive?

Its only the video based (concerts/tv series) that come interlaced regardless of region.

Turn deinterlacing off on a film and watch what happens - nothing!

They play on normal TV's because (in crude terms) they get 'interlaced' by the DVD player on output.

Bottom line, all major film releases in PAL are progressive.

 

[Canary_Jules]

Eureka! A little light has been switched on in my shell-like!

So, back to the cause of my question! I presume that, when fed through an HCPC and PJ, R2 DVDs are invariably superior in picture quality to their R1 counterparts? This will largely be because of the difference in the number of lines, i.e. 525 as opposed to 625?

Jules

 

[KraGorn]

Originally posted by Magsy
Urm maybe I've been mislead all along, but arent all film based DVD progessive?

No you've not been mislead, DVDs ARE interlaced.

As I said above, the 'signal' encoded on the DVD is interlaced, it comes off the DVD and is decoded as interlaced .. only then does it get de-interlaced into progressive scan either by the player, a 'line doubler' or a display device like a plasma/LCD/DLP.

Films and videos require different de-interlaced methods, known as 'bob' and 'weave', but that doesn't alter the fact that on the DVD they're both encoded as interlaced.

 

[KraGorn]

Originally posted by Canary_Jules
I presume that, when fed through an HCPC and PJ, R2 DVDs are invariably superior in picture quality to their R1 counterparts? This will largely be because of the difference in the number of lines, i.e. 525 as opposed to 625?

Theoretcially yes, in practice there are a large number of factors at work.

I suggest you have a read of the articles here at ProgressiveScan, they describe it a lot better than I can. The extra nominal detail a PAL version has is often counteracted by things like the quality of the transfer from film to video, among many others.

 

[Magsy]

Edit because I'm shooting myself in the foot, wait for someone else to come along and explain (properly)

 

[KraGorn]

Originally posted by Magsy
Edit because I'm shooting myself in the foot, wait for someone else to come along and explain (properly)

So where is my explanation wrong?

Originally posted by Magsy
Turn deinterlacing off on a film and watch what happens - nothing!

Of course something happens, you may just not notice it.

Plasmas and LCDs CAN'T DISPLAY interleaved signals, these MUST be converted to progressive. Similarly the vast majority of CRTs CAN'T DISPLAY progressive, nor can some projectors. For this reason DVDs HAVE TO BE interlaced, or else DVD players would have to include progressive->interlaced convertors so you can watch it on your 36" non-progressive TV .. there's no such component in a DVD player.

The point of a progressive scan DVD player is that the de-interlacers in such devices are often better at it than those included in the plasma or LCD/DLP display.