[jbmitch1971]

I have a quick question concerning my Sony RPTV. I have a KP46WT500 and can see no difference between interlaced, progressive, and cinemotion when watching satellite broadcasts. I use a Panasonic dvd-cp72 progressive scan player for dvd's. I can't notice a difference in PQ between running in progressive and interlaced. I have the player hooked up to video 5 through monster component cables. I am wondering if this is normal, or if the television's line doubler is responsible for this lack of difference. Is there really not a dramatic difference between interlaced and progressive or is there something wrong with my set? I have the player set to progressive (both in the menu as well as the progressive scan button on the front). When I switch to interlaced, the screen flickers for a second, then displays the new signal. If I have the DRC in interlaced, I can still see no difference. Thanks for your help.

 

[John Mason]

Only a component-cable hookup? Not using DBS here, only H/DTV cable, but perhaps there's a parallel. I only use the YPbPr outputs of my cable converter when I know there's a source of YPbPr at the other end. And that's only true for about 8 H/DTV cable sources such as HBO and local DTV stations via cable.


Everything else isn't delivered as component signals so I use either the S-video or composite (video) cable converter outputs for these. If I use YPbPr for non-component sources, the converter upconverts everything up to 1080i. And image signals, processed by a mediocre mass-produced converter circuit, also look nearly identical to each other--as well as being fuzzy and washed out. That's because the cheap converter circuits have to process Y/C-format signals (S-video, not H/DTV) into YPbPr.


Interlaced versus progressive component outputs from my DVD player initially looked similar, too, although my set only converts 480i to 480p, not DRC-type upconversion. But I found that certain segments of DVDs, converted to progressive within the DVD machine, are clearly better than the multiple conversions between analog and digital, then deinterlacing in my set. There are many examples, but I found the slow diagonal scan of thatched roofs and theater railings in the DVD opening of "Shakespeare in Love" an excellent example. Very bad straw/railing artifacts in interlaced mode that virtually vanished with a progressive output. -- John

 

[jbmitch1971]

Thanks for the reply. I don't have HDTV, yet. I have the DVD player hooked up with components (figured the YPbPr connection would give the best pic). I guess my question is that what differences am I supposed to be seeing between interlaced and progressive?

 

[John Mason]

I was editing in a 'graph about DVDs while you were replying. -- John

 

[jbmitch1971]

Thanks, John. For some reason, that last paragraph didn't show up. So you saw small differences in some movies and larger differences in others? I'm still learning about a lot of this, so what do you mean when you refer to artifacts? I understand video noise, but am not quite clear on artifacts. Sorry for the basic questions, but need to start somewhere, right?---Jason

 

[John Mason]

Yes, you'll find lots of discussions about this topic--interlace/progressive DVD out--in many forums here, especially DVD hardware. Many other DVD examples are discussed, with specific scenes that illustrate the advantages of DVD progressive out.


With a straight diagonal line in a scene, such as some shipboard guy wires in "Titanic," you might notice stairstepping (jagginess) of the wire in interlace mode but not progressive. In the "Shakespeare" example I cited the straw on the roofs looks like a mass of wriggling worms (bad so-called aliasing) with interlaced YPbPr out from my Toshiba DVD. But the fine straw is crisp and stable with progressive out. Some fairly recent RPTVs provide various format options such as bypassing DRC upconversion, and if your set does perhaps experimenting will produce better images. Not everyone is happy with upconversions, which cuts costs for set makers by simplifying drive frequencies within RPTVs. -- John