A dumb question....

[mgsooner]

But what exactly is a "Progessive Scan" DVD player? What makes a Prog Scan different from just your normal run of the mill player? Does this mean no more horrible layer changes? (Like my player tends to have)

Thanks for the info, I'm sorry I'm so uninformed.

[Flash Ahhh]

mgsooner,

A layer change happens because a disk isn't a single layer, it's dual layer. Different players handle layer changes differently.

Progressive scan has nothing to do with layer changes.

Progressive scan is a video component or signal that processes or displays every scan line of a video frame in sequence rather than cutting part of the scan lines out.

To better understand this, the opposite of a progressive scan is an interlaced scan. Interlaced scan takes a video component or signal and assigns (inserts) alternating scan lines in a video frame which helps reduce flicker without the transmission of extra video information.

Basically an interlaced scan is one that takes an image, and erases every other line and would have a black line in it's place. The video information is the same for every black line. So say you are watching an image with 480 lines of resolution. With the interlaced scan, you'd have 240 signals of actual video, and 240 signals of black lines, but only 241 of total lines had to be sent to the video display source since the black line is repeated. With the progresive scan, you'd get the full 480 lines of actual video image.

Why bother? Well, if you just sent 1/2 the video signal, the picture would be all choppy.

Hope that helps.

-Flash

[chlngr1970]

To expand on Flashs explanation a little, an Interlaced video frame is transmitted in alternating video fields. Field one is the odd scan lines, and field two is the even scan lines. Progressive scan is all 480 lines scaned in order. less flicker and better detail, but a higher bandwith since instead of 240 lines scanned in 1/30 of a second, then field two scanned in 1/30th of a sec, you have all 480 lines scanned in 1/60th of a sec. This is one reason that altough 1080i has more lines of resolution, 720p is considered better.

hope this helps.

j

[Jellodyne]

And to further clarify and elaborate in way too much detail -- The information on a DVD is in an interlaced format. Most TVs can only display interlaced. The player is not actually throwing out half of the data.

The way it works is this -- a TV expects a signal of 60 interlaced 'fields' a second, and each field consists either the odds or the even scanlines. Films are shot 24 frames a second. For a DVD, thypically each film frame is broken up into 2 fields which are stored sperately, and the fields are shown in a pattern which yields an interlaced 60 fps. Now, 24x2=48 < 60 so there is a pattern, or cadance, which the film frames follow and also they are usually flagged in the bitstream as to what type of frame they are.

If you have an HDTV you are capable of progressive scan disply, which is to say, all the scanlines, odd or even, every frame. A progressive scan player either reads the flags or detects the cadence (which is called 3:2 pulldown, the 3:2 referring to the cadence used) and stitches the odd and even frames together and outputs a 'progressive scan' signal. The benefit of this is less flicker and less artifacts on motion. With an interlaced display, if you have an object moving across the frame, it may look like this

-

  -

-

  -

-

because half of the lines move, then the other half, and so on. A progressive display, you just get

  -

  - 

  -

  -

  -

So it looks better.

[chogan]

To tie up and greatly simplify what everyone has said, the main difference you will see (or at least what I see) is smoother edges on objects in the picture.

[SeanL]

Originally posted by Flash Ahhh
To better understand this

Originally posted by chlngr1970
To expand on Flashs explanation a little

Originally posted by Jellodyne
And to further clarify and elaborate in way too much detail

Originally posted by chogan
To tie up and greatly simplify what everyone has said

Are we clear on progressive scan now?

[Wirehed]

Originally posted by SeanL
Are we clear on progressive scan now?

Ok, but how does HDTV work?

[Taxi]

For an excellenet description of what happens regarding interlaced/progressive video, might I suggest you go here, and scroll down to the grey area.

[palebluedot]

How HDTV Works

I've always found howstuffworks.com gives nice, fairly easy to understand descriptions of things. The HDTV page talks about HDTV and Progressive/Interlace.

[tomdkat]

Originally posted by Taxi
For an excellenet description of what happens regarding interlaced/progressive video, might I suggest you go here, and scroll down to the grey area.

Thanks for posting this link, so I don't have to....

Peace.....

[Wirehed]

I was joking Palebluedot, but thanks for the link.

[palebluedot]

Anything to get my post count up so I can get a custom avitar.

[chlngr1970]

Remember, it's Quality, not quantity that counts.

j

[sub780lime]

Originally posted by palebluedot
Anything to get my post count up so I can get a custom avitar.

expect more admin thrashing here very soon, well just kidding, but im sure you'll get more reminders from our fearless leaders
as changler said, its what you write not how many times, padding your post count is a big no no here, so if your doing it i would suggest not mentioning it

-lates

[octopus1256]

In reply to all those techie answers...

So, if I have bought a US copy of a DVD, but my DVD player isn't Prog Scan compat, and my TV ain't HD, then I get Interlaced 480i?
So ins't there any way around this without buying a new DVD player and TV to get Prog Scan? Because I 'see' black lines when watching DVD's.

[palebluedot]

Originally posted by sub780lime
expect more admin thrashing here very soon, well just kidding, but im sure you'll get more reminders from our fearless leaders
that is changler said, its what you write not how many times, padding your post count is a big no no here, so if your doing it i would suggest not mentioning it

-lates

As you said before, I was just joking, but thanks for the advice.

[tomdkat]

Originally posted by octopus1256
So, if I have bought a US copy of a DVD, but my DVD player isn't Prog Scan compat, and my TV ain't HD, then I get Interlaced 480i?
So ins't there any way around this without buying a new DVD player and TV to get Prog Scan? Because I 'see' black lines when watching DVD's.

The short answer is: No. Even if you got an external de-interlacer, your TV would have to support a progressive video input.

What kind of DVD player do you have now (post make/model). Possibly upgrading to a "better" interlaced DVD player would help with your video "issues".

Peace.....