Progressive scan...

Discussion in 'Archived Threads 2001-2004' started by Brad Craig, Feb 2, 2002.

  1. Brad Craig

    Brad Craig Stunt Coordinator

    Joined:
    Feb 1, 2002
    Messages:
    58
    Likes Received:
    0
    I know progressive scan on dvd players is better and is only needed if you have a HDTV capable TV...
    Could someone tell me why progressive (in layman terms) is better than traditional dvd players or point me to a website...
    Thanks... [​IMG]
     
  2. Chris Tsutsui

    Chris Tsutsui Screenwriter

    Joined:
    Feb 1, 2002
    Messages:
    1,865
    Likes Received:
    0
    Instead of splitting each video frame into two sequential fields like interlaced scan. Progressive scan displays the entire frame in a single sweep. So, where a standard DVD player's 480i output displays 30 frames (60 fields) per second, a progressive scan player's 480p output displays 60 full frames per second. Progressive-scan picture quality is more film like, with more fine detail and less flicker.
    Since I don't have an HDTV, I like watching movies on computer monitors because not only do they have great quality but are progressive scan.
    $65 for a Pioneer Slot load DVD 16x drive
     
  3. Stefan A

    Stefan A Second Unit

    Joined:
    May 27, 2001
    Messages:
    397
    Likes Received:
    0
    I have found a few movie scenes where you can compare the 2 and easily see the difference. Opening of Shakespeare in Love as the camera is panning across the theater. Look at the balisters. They look pretty smooth on P scan players but bounce along on interlaced. Car grills. When the car in Saving Private Ryan pulls up to inform Mom of sons death. The grill flickers with interlaced but is solid on P Scan. Of course, there are probably thousands of examples - but those have helped me to see the difference.
     
  4. Michael Reuben

    Michael Reuben Studio Mogul

    Joined:
    Feb 12, 1998
    Messages:
    21,763
    Likes Received:
    2
    To understand why progressive scan is better, it helps to know a little about the process by which film is transferred to video. The site below has a very good explanaion, which concludes with a discussion of progressive scan:
    What The Heck Is 3:2 Pulldown
    M.
     
  5. Brad Craig

    Brad Craig Stunt Coordinator

    Joined:
    Feb 1, 2002
    Messages:
    58
    Likes Received:
    0
    Can someone explain why a normal TV which is capable of 525 lines of resolution right, can't handle progressive scan which outputs 480 lines of resolution???

    I mean I'm told you need a computer monitor or HDTV which is cabaple of 1080 lines of resolution right, to see the benefits of progressive scan dvd players...
     
  6. Bob McElfresh

    Bob McElfresh Producer

    Joined:
    May 22, 1999
    Messages:
    5,182
    Likes Received:
    0
    Standard NTSC is called 480i - the "i" means INTERLACE

    All the odd-number rows are drawn first: 1/3/5/... Then the beam goes back up and fills in the even lines: 2/4/6/...

    Look at a ordinary big-screen TV. See the horizontal lines? These are called "scan lines", but they are caused by the delay between drawing rows 1 & 3, then filling in row 2 later.

    Progressive scan is... Progressive or "natural order". The video rows are drawn in sequence: 1/2/3/4/...

    This gives you a much smoother, un-broken picture.

    (Your computer monitor is progressive by the way)

    If you send Progressive signals to a normal TV, it will not understand the signal.

    Does this help?
     
  7. Bob McElfresh

    Bob McElfresh Producer

    Joined:
    May 22, 1999
    Messages:
    5,182
    Likes Received:
    0
    PS: Most HDTV's are capable of 1080i, but you dont technically need one like that for Progressive Scan DVD's.

    Here is the problem: What is HD?

    All of the following formats have been proposed:

    480i - needs to accept this to be backwards compatible

    480p

    520p

    520i

    720p

    720i

    1080i

    Because it has not fully been standardized yet, all these different formats are possible. So current gen HDTV's tend to be able to accept all of these. So that is why people tell you to get a TV capable of 1080i - it's a hedge against the eventual standard.
     
  8. Vince Maskeeper

    Vince Maskeeper Producer

    Joined:
    Jan 18, 1999
    Messages:
    6,499
    Likes Received:
    0
    The question is not one of pure resolution, but rather one of sync rates.
    Think about it:
    480 lines, updated ever other line for 30 frames, 60 fields is one scan rate-- the set is drawing only 240 lines per field 60 times every second- so 14400 lines per second.
    480 lines, updated entire fields for 30 frames, 60 times a second is another -- the set is drawing 480 lines per field 60 times every second- so 28800 lines have to be drawn per second..
    Standard NTSC TVs are not designed to be able to redraw fast enough to draw 480 complete lines, 60 times per second (28800 lines per sec). Instead they are only able to draw HALF the lines 60 times per second-- the picture is interlaced.
    You're talking about a double in scan rate, twice as many lines to draw per second.
    Just like the TV might be able to handle "525 lines"- but if you asked it to redraw all of those 525 lines 10000 times per second, there is NO WAY IT WOULD HAPPEN. Lines of resolution is simply one issue- how it uses those lines is yet another (how fast can it refresh them?).
    I could build a display that could resolve 4000 lines, but could only update those 4000 lines one time every second... it wouldn't be able to display HDTV video, or ntsc for that matter- as it was only able to redraw once a second...
    Certainly this issue of sync of standard NTSC TVs wouldn't be a difficult issue to fix as the resolutions match- but it involves building in faster refresh abilities into the set. Many modern tvs have added this ability as a feature-- but it simply is not part of the NTSC specification to which most older TVs are designed. Newer NTSC and HDTV sets are adding the ability to redraw that fast.
    You see it in HDTV more often because the set already has to support higher sync rates (1080i being about 32400 lines per second) -- not having anything to do with resolution directly- rather the ability to draw and redraw lines as fast as is needed.
    Hope that clears it up, please let me know if you can see the difference now.
    -Vince
    PS; These numbers are not exact- but rather to explain it simply. TV refreshes are actually based on a 29.97 system- so the numbers above are just as an example.
     
  9. RalphH

    RalphH Auditioning

    Joined:
    Jan 28, 2002
    Messages:
    3
    Likes Received:
    0
    Actually, as Chris pointed out, progressive scan has some better picture quality over interlaced (3:2 pulldown, 60 frames per second - a lot of technical hoopla); basically it converts the video display to film display for a better picture. However, a lot of HDTVs on the market (I personally have a Toshiba 42" widescreen) have a film mode for such inputs as dvd. The film mode of the HDTV has the same effect as a progressive scan dvd player, so to infer that it would be more beneficial to any HDTV would be incorrect. You should check the capabilities of your HDTV to see if has a film mode, otherwise you'll be spending extra money on a feature you may already have.

    Ralph
     
  10. Vince Maskeeper

    Vince Maskeeper Producer

    Joined:
    Jan 18, 1999
    Messages:
    6,499
    Likes Received:
    0
     
  11. Seth Paxton

    Seth Paxton Lead Actor

    Joined:
    Nov 5, 1998
    Messages:
    7,585
    Likes Received:
    0
    BTW, NTSC only has 480 lines of VIDEO 525 is total lines (just like ATSC 1080 lines is VIDEO, but it's a total of 1125 lines, iirc), but those other lines are for data and timing for retrace (going back to the top from the bottom). Moving the beam back to the top of the screen takes time and part of the time used is literally the time that would be devoted to, say, line 519 or line 3.

    Line 21 carries your V-chip info and closed-captioning info. You can scan it by adjusting the size of your scan area on-screen and you will see the data as white dashes and dots, just above the beginning of video.

    Anyway, THE REASON some TV's cost more just to scan faster is because it takes POWER to move the beam so quickly back and forth. The big points are:

    Going back from the right to the left. You only have the short time from the end of one line of info and the beginning of the next line. If you double how fast you are going through these lines, you just halved the time you have to go back.

    Adjusting electrical signals is sort of like springs. If you go moving quickly in one direction you can go flying past your target (overshoot) before bouncing back and forth until settling on your target spot. So you need better electronics to get the beam back across the screen quicker without overshooting.

    The other point is going from the bottom back up to the top, the time between frame 1 and frame 2. At 60 frames per second you have 1/60th of a second per frame. And only about 1/10th of that is available to get back to the top of the screen cleanly (if that). 1/600th of a second rather than 1/300th is a lot less time.

    So it's no screw job or anything. Older sets just couldn't hack it. It's also one of the reasons (among several, like multi-sync capability) why CPU monitors cost so much per screen size.
     
  12. Seth Paxton

    Seth Paxton Lead Actor

    Joined:
    Nov 5, 1998
    Messages:
    7,585
    Likes Received:
    0
    Yes, you never want to go out into the analog world unless necessary. Vince is totally right. Maybe a kick-ass analog scalar won't f**k up so much that it can still beat a half-ass progressive DVD player, but that's rare.

    The great thing about DVD is that the data is all digital and you can do what you want with it without dealing with analog noise. But once it goes out the back in analog waves (component, s-vid, composite) you can only pray the cables are good, the analog detection circuitry is decent, and that the digital sampling is good. That's a lot to introduce to the system needlessly.

    You will spend a hella lot less on a progressive DVD player than you would on a DVD player and an analog scaler good enough to match the progressive player's output.

    TV scalers...good luck, it's not the highest priority, trust me (i've done it for a living).
     
  13. Michael Buck

    Michael Buck Auditioning

    Joined:
    Jan 9, 2001
    Messages:
    4
    Likes Received:
    0
    I am assuming that "internal scaler" and "internal line doubler" mean basically the same thing. If this is incorrect, please correct me...

    Anyway, I have a Toshiba TW65X81 65" RPTV, with an internal line doubler. I am ready to replace my original Panasonic DVD-A310 (from '98) with something newer, but am not sure if a progressive scan player will (a) be any significant improvement over the current non-progressive player and line doubler combo, and (b) whether the RPTV will understand the incoming progresive signal, so that the DVD and line doubler will not fight with each other. Might I have to somehow disable the internal line doubler while using the DVD, only to have to re-enable it for LD or VHS use?
     
  14. Michael Reuben

    Michael Reuben Studio Mogul

    Joined:
    Feb 12, 1998
    Messages:
    21,763
    Likes Received:
    2
    With Toshiba's Colorstream Pro inputs, the internal line doubler is automatically bypassed when the set detects a 480p signal. All you have to do is switch to the Colorstream input.

    As for whether you'll see a major improvement with a progressive player, that's largely a subjective judgment. I see a big difference on the TW65H80, but your mileage may vary.

    M.
     
  15. Jim Ro

    Jim Ro Auditioning

    Joined:
    Jan 26, 2002
    Messages:
    5
    Likes Received:
    0
    Michael,

    What settings do you have your Toshiba 65H80 set to? I have the 56H80 (same thing only smaller) and am not sure I am set up properly.

    Thanks
     
  16. Bob McElfresh

    Bob McElfresh Producer

    Joined:
    May 22, 1999
    Messages:
    5,182
    Likes Received:
    0
    HEY BRAD! Did you get your original questions answered?
    If we blow you away with some terms, please cut-paste and ask questions. Unlike other sites, we dont try and build ourselves up by trouncing people who post simple questions. (Well, not too often anyway [​IMG])
    But we can cheerfully go off onto detailed tangents if you dont draw us back to something you want to know.
     
  17. Michael Reuben

    Michael Reuben Studio Mogul

    Joined:
    Feb 12, 1998
    Messages:
    21,763
    Likes Received:
    2
     

Share This Page