How Important is Progressive Scan?

[heyjjjaded]

I just bought a new Sony 50" LCD HDTV, but my DVD player is not progressive scan. I love watching DVDs and have always been happy with my DVD player (Sony NS325), but now that I have my first digital HDTV, I'd like to know how necessary a progressive scan DVD player is. Thanks!

[Shocker Milwaukee]

How Important is Progressive Scan?

It's very important! Run right out and get it!



(With progressive scan DVD players being as cheap as they are, it's worth it.)

[BJ_M]

your lcd converts everything to progressive scan and also removes pulldown anyway .. so dont worry about your dvd player ...

also - in reality -- progressive 24fps is not as smooth as 30fps anyway ... 24fps is not some magic number , but the lowest frame rate they could get away with in theaters and people would not complain to much .. they did this (come up with 24) to keep production costs down -- not quality up ..

imax and other big screen are at 30 - 60 fps for good reason ..

there is WAY to much on this forum (and others) trying to reduce interlaced shot material to progressive for no good reason ..


i think LS would agree with me there ..

[Marco33]

Like they say in the south...

'the proof is in the puddin'

I didn't see all the fuss either untill I got my new prog scan Sony.

[doppletwo]

24 fps oly looks good on film because film doesn't have set resolution and pixel placement.

The motion blur on film helps give film the illusion of motion at such a low frame rate. Digital formats have strict resolutions and strict pixel placement. The high the frame rate the better with digital. Well there is a limit. People with the fastest vision can only see about 120 fps per second. And I am talking about Ted William the only man to hit .400 in the modern era of baseball. Ted williams claimed to be able to see the individual threads of the baseball on 100 mph fastball.

Why do all the TV manufacturer say Progressive scan is 60 fps?

I don't own a progressive scan TV and don't use one often enough to know but all the TV manufacturers claim progressive scan is 60fps.

And they say Regular TV (interlace) is 60 half frames per second.

Are all of the companies llying?

Just a question I am curious please don't take this a a personal attack.

[adam]

I don't understand what 24fps has to do with this. Don't all progressive scan dvd players output 30p?

IMO, if you spend that much on an HD tv you should fork out at least a few hundred more for a decent progressive scan dvd player or better yet, get one of the new ones with internal scaling which can upconvert to HD.

[BJ_M]

I don't understand what 24fps has to do with this. Don't all progressive scan dvd players output 30p?

IMO, if you spend that much on an HD tv you should fork out at least a few hundred more for a decent progressive scan dvd player or better yet, get one of the new ones with internal scaling which can upconvert to HD.

no they output 24fps P or 29.97 I (ntsc)

even if you encode @ 30P (29.97) and create a dvd , the dvd player will spit it out at 29.97I with no 24P out ... all LCD , plasma and dlp projection and flat panels are progressive only internally ..

so if you input interlace (non film source) into them - they convert it to progressive and dont look so hot often ... some are MUCH better than others on this score ..

[adam]

I am fairly certain that is not true. Progressive scan DVD players output either 480p or 480I.

With 480p output each whole frame is refreshed every 1/60th of a second.

With 480I output, each field is updated every 1/60th of a second.

I don't believe it is possible for current progressive scan dvd players, to output current DVDs at the equivalent of 24fps (refresh at 1/48th of a second).

Please correct me if I'm wrong. Howstuffworks used to have a great explanation of what progressive scan does, but I can't seem to find it anymore

[BJ_M]

i am certain --- or i have been doing it wrong for years as a living (possable) ..

see here http://www.hometheaterhifi.com/volume_7_4/dvd-benchmark-part-5-progressive-10-2000.html

[heyjjjaded]

Thanks for the help, everybody. I guess I just don't fully understand what progressive scan DVD players do & whether or not I need one with my new tv. I am perfectly willing to spend the money on one, but I would just like to find out what the need is ... you know, what will a progressive scan player do that my current player won't? I guess I don't just want to throw my money away. Thanks again.

[adam]

Doesn't that article just say exactly what I did though?

Progressive Scan

Progressive displays, such as high-performance CRT/LCD/DLP/LCOS projectors and the new HDTV-ready TVs, can show progressive scanned images as opposed to interlaced. We learned above that an interlaced display shows 60 fields per second. But with progressive, each scan of the CRT face is a complete picture including all scan lines, top to bottom, now called a frame, and we are showing 60 of those per second.

This means a DVD encoded at 23.976fps with pulldown flags will play back at 60fps, or 480p. If it were encoded at 29.97 interlaced it would be played back at 60 fields per sec, or 480i. I don't see how you can ever get a multiple of 24 either in frames or in fields.

I understand that progressive scan dvd players use the 3:2 pulldown flags to emulate 24fps movement, but like that article says,

The progressive output of a DVD player should assemble 2 fields from each film frame and create a complete progressive frame that looks just like the original film frame. You should now be thinking that the DVD will once again have 24 frames to show in one second . . . but as we said the progressive display is operating at 60 frames per second.

I don't believe it is accurate to say that progressive scan dvd players output 24fps footage if the images are always refreshed at 1/60th of a second. That's either 60 frames per second or 60 fields per second, depending on source. But under no cirumcstances will it be 48 frames per second or 48 fields per second.

I thought this was one of the major selling points of HD-DVD and Blue-ray; that we finally get to watch our DVDs in their native framerate of 24fps (assuming it was shot on film.)

[doppletwo]

Yeah, Adam is right the link you provided, BJ_M, says that progressive scan is 60fps not 24fps, but it uses a 24fps source and does that 3:2 pulldown thing.

[lordsmurf]

Interlaced is fine. I totally agree BJ_M, too many people are wahoo over nothing. Progressive scan may "output" 30-60fps (or whatever), but it's just duplicating the 24fps material. That's no good either. No better than interlaced pulldown output.

Leave your source alone.

Let the tv do the work. Or at very least, let a GOOD DVD PLAYER do the work. Cheap tv, cheap player, probably not all that hot results. Or better yet, get one of those fancy/expensive conversion device (Faroujda makes some I believe) to do the work for you if you REALLY need progressive, and done well.

So... how important is it? It's a good marketing term, that's about it.

[adam]

Whether or not to allow your tv or player to deinterlace a 29.97i source is a subjective decision which depends on your tastes, as well as the quality and deinterlace modes supported by either your tv or player, whichever you are letting do the work.

However, the fact remains that the vast majority of theatrically released movies on NTSC DVDs are stored using progressive frames and telecined to 29.97i on the fly. If you have an HD tv, and typically watch these kinds of DVDs, which I assume most movie lovers do, then progressive scan is anything but a marketing gimmick.

Most HD sets will have some form of line doubling or descaling options, and some may or may not have an additional 3:2 pulldown detection, or film mode. If yours doesn't, then you are seriously losing out on a tremendous amount of quality by using a standard dvd player. Even if your player does support some or all of these options, the fact is that a good DVD player can usually do it better. Read some reviews on your set, and then make an informed decision whether an external progressive scan player is needed, because in my opinion, depending on your tv set a progressive scan player really is needed if you want the best playback quality of your DVDs.

60p looks a HELL of alot better than 30i.

[BJ_M]

For every film frame that had three fields made from it, the third field is a duplicate of the first, and (if the MPEG-2 compression is set right) won't even be stored on the DVD. Instead of encoding the duplicate fields, the DVD flags repeat_first_field and top_field_first are used to instruct the MPEG decoder on what to do. The progressive output player will assemble 2 fields from each film frame and create a complete progressive one that looks just like the original film frame. In order to space them out, the DVD player shows the complete frames in this order: 1, 1, 1, 2, 2, 3, 3, 3, 4, 4 and so on. It is 24fps (close)
Some of the better progressive tv's and displays and video projectors have usually what is known as a cinema mode and will reassemble these back to 720P to avoid that little extra flicker ...
Note that many so called HD or HD ready displays do not truly handle progressive in this manner though - a good clue is if they can display 720P and not just 480i / 480p and 1080i .

[BJ_M]

I have now several HD units at home and yes they look good, now if only the looked good on cable (very rare) and also now i am more noticing badly encoded dvd's (which were annoying before but now really annoying) ..

[live4ever]

Maybe look into a DVD player that has DVI/HDMI out and up-converts to a HD resolution (since that 325 model is quite old nowadays).

Sony has a new one for just over $230ish, the DVP-NS975V, since you have such a nice LCD panel a better DVD player would be ideal.

http://www.sonystyle.com/is-bin/INTERSHOP.enfinity/eCS/Store/en/-/USD/SY_DisplayProduc...DVD_DVDPlayers

[adam]

With all due respect, yes the source is 24fps and the progressive scan decoder uses the pulldown flags to approximate the "look" of film rate playback but that doesn't change the fact that the movie is physically being played back at 60 frames per second. The 3:2 pulldown detection modes merely reduce the bad effects of the telecine to 1/60th refresh rate, but that telecine is still being done. Progressive scan DVDs players physically cannot output 24 frames per second, or any derivation of 24.

Maybe I'm being overly technical, but in my mind, saying that you get 24fps playback implies that the pulldown flags are ignored, or bypassed, and you are just accessing the original 24fps progressive frames and no others. This is obviously not true.

[BJ_M]

Maybe look into a DVD player that has DVI/HDMI out and up-converts to a HD resolution (since that 325 model is quite old nowadays).

Sony has a new one for just over $230ish, the DVP-NS975V, since you have such a nice LCD panel a better DVD player would be ideal.

http://www.sonystyle.com/is-bin/INTERSHOP.enfinity/eCS/Store/en/-/USD/SY_DisplayProduc...DVD_DVDPlayers

if you mean me -- i have a HD server that can play HD mpeg2 files .. as well as two Samsung HD931 up-rez dvd players and a pioneer RP82 (and a couple others) .

LCD panels so far dont look to good -- but then plasmas dont either .

I'll stick with DLP video projection and CRT displays ...

[doppletwo]

This thread has almost become a flame war I am getting out of here before I get in trouble again.

Sorry about this post being off topic. just commenting on how it looks.

[adam]

No, not a flame war at all. Like I said, my posts give all due respect. I just think the comments about the limitations of 24fps playback are inapplicable when discussing the benefits of a progressive scan dvd player.

[BJ_M]

i realized that we were saying the same thing but looking at it from two different perspectives ... or approaches..

no flame war - just a discussion ...

[RottenFoxBreath]

Progressive scan DVDs players physically cannot output 24 frames per second, or any derivation of 24.

Not True,the LG5620 home theatre system outputs in PAL and NTSC progressive with the latter being slightly more stretched vertically and a slight addition of the NTSC "blur".
a simple flick of a switch on the back enables or disables the 24 or 29 fps.(i own one of these) PAL progressive being the better picture,slightly better than RGB scart. much smoother,and clearer,even on a 51" RP tv(toshiba brand,and is PAL and NTSC progressive)

[adam]

Yes actually it is true. Read your manual, that setting cannot be outputting 24fps content because this is not currently possible with progressive scan DVD players, or our current DVD standard.

The process of progressively scanning a DVD merely line doubles. You CANNOT get 24fps output. Maybe your player does something other than a progressive scan. The only information I can find on that package says the player's methods are "based on progressive scan technology."

My assumption is that your 24fps setting is merely a toggle to specify whether the source is film based or NTSC. In other words, it is a manual 3:2 pulldown option as opposed to the automatic 3:2 pulldown detection methods used in higher end dvd players.

[BJ_M]

since that model is sold in europe - may have something to do with if your tv can play back pal 60 or not

[Cornucopia]

I hope this isn't considered just a lot of hot air, 'cuz I'm pretty sure that I actually read this online recently. I just can't find anything immediately to back me up...

FWIW, some progressive scan DVD players will output not only 29.97i (standard) and 29.97p, but also 60p and even 72p. They can work with computer type monitors (just about all PC monitors should have 72Hz scan rate). It does this by using a 24fps progressive signal and spits out:
Frames A, A, A, B, B, B, C, C, C etc. This is much like theatre film gates that either double (48Hz) or triple (72Hz) the frame rate. Judder doesn't get worse, because there's really no irregularity in the timebase, but it's not REAL 72fps either. That's one reason IMAX looks so good--60 or 72 Hz progressive is SMOOTH!

Also, BJ_M didn't mention this, mainly I think because he was working from a certain angle, but there are some quite strong benefits to showing true progressive frames:
Lack of DotCrawl, LineJitter, Moire, and similar strobing effects.

I've always felt that while 24fpsProgressive was too slow (and noticeable to my eyes), 29fpsInterlaced was a not-too-well-executed cheat. I live for the day when we can all watch 60-120Hz progressive at home! Hopefully HDTV (especially 720p) will vindicate my opinion and quench my visual thirst.

Scott

[handyguy]

"Thanks for the help, everybody. I guess I just don't fully understand what progressive scan DVD players do & whether or not I need one with my new tv."

You can buy a cheap on at Sears probably for under $30 & check yourself.

[BJ_M]

The Pioneer PDP-4340HD runs on a 72Hz vertical refresh rate. That's an exact multiple of the 24 frames per second at which films are displayed, enabling the panel to use a video-processing technique called 3:3 pull-down ..

So does the PIONEER PDP-5045HD ..

several more models should i expect to be out soon -- doesnt mater what dvd player you use with them ..

many video projectors can do the same thing also ..

[W_Eagle]

Pardon my French, or Hebrew.
What is the importance of Progressive Scan in the PAL world?

[BJ_M]

see above -- same thing