Progressive scan capability question
09-22-04, 12:12 AM
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Progressive scan capability question
OK, excuse my further stupid questions.
I assume if we want to have prme quality in watching DVD, in terms of video quality, basically we've got to have a DVD Player with good prog. scan capability and same goes with the TV. Both prog. scan chip (on TV & player) should be of equal quality. Is this assumption correct?
Then what would the display look like (good/bad) if:
1. My player prog. scan is of bad quality but my TV prog. scan is better?
2. My player is not prog. scan but my TV has prog. scan?
3. My player prog. scan is better than the TV's prog. scan?
Of course it is assumed we use same DVD for testing.
Also, prog. scan is only for NTSC format? What if the DVD is PAL? (Say we have a PAL-NTSC player)
I assume if we want to have prme quality in watching DVD, in terms of video quality, basically we've got to have a DVD Player with good prog. scan capability and same goes with the TV. Both prog. scan chip (on TV & player) should be of equal quality. Is this assumption correct?
Then what would the display look like (good/bad) if:
1. My player prog. scan is of bad quality but my TV prog. scan is better?
2. My player is not prog. scan but my TV has prog. scan?
3. My player prog. scan is better than the TV's prog. scan?
Of course it is assumed we use same DVD for testing.
Also, prog. scan is only for NTSC format? What if the DVD is PAL? (Say we have a PAL-NTSC player)
09-22-04, 01:57 PM
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Let's start with the basics. The first thing you need in order to use a progressive scan DVD player is a display the will accept a progressive signal. This display is either an EDTV or a HDTV but SDTVs won't. Now either one of these EDTVs or HDTVs will also have their own deinterlacer built in for sources like 480i cable or VHS.
When you feed a progressive signal to the display from a progressive scan DCD player the TV's built in deinterlacer is bypassed. If you turn the progressive output from the player off and feed the TV a 480 interlaced signal then the built in deinterlacer of the TV kicks in and converts 480i to whatever native resolution the display has. This part is important since if one of the TV's native displays is anything but 480 progressive then a progressive scan player might not be needed. In other words if your TV takes any 480 interlaced or progressive signal and converts it to 540p, 720p or 1080i before displaying the image then there is not real point in buying a player that outputs 480p. The whole point of buying a good progressive scan player is to see the 480p image that it outputs but if that signal is being converted by the TV to something else then why bother. You could just as easily let the TV convert the original 480 interlaced signal and avoid one conversion.
If your TV does display a 480p natively then you'll need to test both it's output and the players 480p output to see which is better. Most find that the player wins in this contest if the player uses a superoir deinterlacing chip like the Faroudja chip found in the older Pannys and some of the Denons. If not that it can be a close call.
As for NTSC to PAL that's an area unfamiliar to me that somebody else will need to answer.
When you feed a progressive signal to the display from a progressive scan DCD player the TV's built in deinterlacer is bypassed. If you turn the progressive output from the player off and feed the TV a 480 interlaced signal then the built in deinterlacer of the TV kicks in and converts 480i to whatever native resolution the display has. This part is important since if one of the TV's native displays is anything but 480 progressive then a progressive scan player might not be needed. In other words if your TV takes any 480 interlaced or progressive signal and converts it to 540p, 720p or 1080i before displaying the image then there is not real point in buying a player that outputs 480p. The whole point of buying a good progressive scan player is to see the 480p image that it outputs but if that signal is being converted by the TV to something else then why bother. You could just as easily let the TV convert the original 480 interlaced signal and avoid one conversion.
If your TV does display a 480p natively then you'll need to test both it's output and the players 480p output to see which is better. Most find that the player wins in this contest if the player uses a superoir deinterlacing chip like the Faroudja chip found in the older Pannys and some of the Denons. If not that it can be a close call.
As for NTSC to PAL that's an area unfamiliar to me that somebody else will need to answer.
09-23-04, 09:06 AM
#3
DVD Talk Legend
Originally posted by chipmac
This part is important since if one of the TV's native displays is anything but 480 progressive then a progressive scan player might not be needed. In other words if your TV takes any 480 interlaced or progressive signal and converts it to 540p, 720p or 1080i before displaying the image then there is not real point in buying a player that outputs 480p. The whole point of buying a good progressive scan player is to see the 480p image that it outputs but if that signal is being converted by the TV to something else then why bother.
This part is important since if one of the TV's native displays is anything but 480 progressive then a progressive scan player might not be needed. In other words if your TV takes any 480 interlaced or progressive signal and converts it to 540p, 720p or 1080i before displaying the image then there is not real point in buying a player that outputs 480p. The whole point of buying a good progressive scan player is to see the 480p image that it outputs but if that signal is being converted by the TV to something else then why bother.
1) The interlaced 480i video is deinterlaced to 480p.
2) The 480p video is scaled to the display's native resolution.
Deinterlacing quality can vary wildly, and generally the cheap chips built into TVs do a poor job of it. A decent progressive scan DVD player will likely do a better job.
Therefore, even if the TV's native resolution is not 480p, you want to feed it the best 480p signal you can before it does the scaling.
Here's a lengthy article that explains more about progressive scan than you ever wanted to know:
http://www.hometheaterhifi.com/volum...e-10-2000.html
09-23-04, 02:18 PM
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Josh why do you think that it's important to feed a scaling TV the best progressive signal before it's scaled to another resolution?
If you have a player with superior deinterlacing and the TV is going to convert that signal from analog to digital and scale it to 540p or 720p for dispaly it doesn't matter if the signal was interlaced or not since the TV is creating its own progressive output. Furthermore the scaling process in many cases introduces artfacts that negate any positive influence that the player's deinterlacing performed. In the cases where the signal is being scaled to display at 1080i the signal is being converted back to an interlaced signal anyway. Also in many cases the TV will convert to 1080i before converting the signal to 540p or 720p for display.
Finally in the very first sentance of mine that you quoted I specifically stated that a progressice player might not be needed. I said might because as withg everything your milage will vary. You can buy a high end progressive player and feed the TV a progressive signal and then switch the output to interlaced and see which you think is better. But on a non-480p native display how can you say you're seeing the full benefit of that progressive player if the signal is being watered down by all of that postprocessing? Oh and that link you provided was written with 480p displays in mind if I'm not mistaken since that was before all of the TV manufacturers decided to cut costs but not having two native resolutions.
If you have a player with superior deinterlacing and the TV is going to convert that signal from analog to digital and scale it to 540p or 720p for dispaly it doesn't matter if the signal was interlaced or not since the TV is creating its own progressive output. Furthermore the scaling process in many cases introduces artfacts that negate any positive influence that the player's deinterlacing performed. In the cases where the signal is being scaled to display at 1080i the signal is being converted back to an interlaced signal anyway. Also in many cases the TV will convert to 1080i before converting the signal to 540p or 720p for display.
Finally in the very first sentance of mine that you quoted I specifically stated that a progressice player might not be needed. I said might because as withg everything your milage will vary. You can buy a high end progressive player and feed the TV a progressive signal and then switch the output to interlaced and see which you think is better. But on a non-480p native display how can you say you're seeing the full benefit of that progressive player if the signal is being watered down by all of that postprocessing? Oh and that link you provided was written with 480p displays in mind if I'm not mistaken since that was before all of the TV manufacturers decided to cut costs but not having two native resolutions.
09-24-04, 03:57 PM
#5
DVD Talk Legend
Originally posted by chipmac
If you have a player with superior deinterlacing and the TV is going to convert that signal from analog to digital and scale it to 540p or 720p for dispaly it doesn't matter if the signal was interlaced or not since the TV is creating its own progressive output.
If you have a player with superior deinterlacing and the TV is going to convert that signal from analog to digital and scale it to 540p or 720p for dispaly it doesn't matter if the signal was interlaced or not since the TV is creating its own progressive output.
Furthermore the scaling process in many cases introduces artfacts that negate any positive influence that the player's deinterlacing performed.
Conversely, a good scaler in the TV will not fix bad deinterlacing artifacts. Deinterlacing has its own artifacts that are unrelated to scaling.
In the cases where the signal is being scaled to display at 1080i the signal is being converted back to an interlaced signal anyway.
But on a non-480p native display how can you say you're seeing the full benefit of that progressive player if the signal is being watered down by all of that postprocessing?
It's always in your best interest to feed the television the best quality signal that you can and have the TV do the least processing on its own that it needs to. Ideally, this means running your DVD player through a quality external scaler. Those are expensive, however, and a good place to start is at least a good progressive scan DVD player.
09-24-04, 08:03 PM
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Josh I don't have the time for a long winded debate on this subject. It's seems you've got your opinion and I've got mine. Like I said earlier if you have a display that doesn't show 480p natively you may not need a progressive player. I stand by this statement and that it's is dependent on the individual and the components they own. Some will see a slight difference prefer the 480p output from the player and some will prefer the interlaced output.
At least we mostly agree here. Yes deinterlacing and scaling are two separate and different processes but how it's done and when is dependent on the make and model. Some may scale before and some after but in any case if the 480p signal is scaled then you're not seeing the original true output of the player which has been my point all along. The TV's scaling can introduce artifacts into that wonderful 480p output that a display that doesn't scale wouldn't do. Notice I said can because not all TV's will show these artifacts and not everyone will even notice it if it did.
Agreed.
This is a new one on me. What makes you think that the scaling isn't done on the interlaced signal? I won't argue that it isn't ever done this way but why deinterlace and than scale when you can just scale and eliminate one step?
Well except for some EDTVs there are no fixed pixel displays that show 480p native so they were never meant to be included in the discussion since they must be scaled. There is no choice. My argument is that scaling can introduce artifacts that can deteriorate a great 480p image and that if the display is set at 1080i which is interlaced then why bother to send it a deinterlaced signal that only needs to be reinterlacced. You can get the same scaled 1080i image from a 480 interlaced signal.
I think we've both made our points and it will be up the the individuals to decide for themselves using their equipment.
Originally posted by Josh Z
You're working under a couple of miconceptions here. First off, converting the progressive analog output of the DVD player to digital for scaling does not affect the deinterlacing of the signal. All this means is the the video signal bypasses the TV's deinterlacing chip and goes straight for the scaler. If the TV's deinterlacer is poor (as most are), this is a good thing.
This is a generalization that is largely untrue. Deinterlacing and scaling are two separate processes that each have their own potential artifacts. If the TV has a bad scaler, that doesn't negate the benefits of good deinterlacing. All it means is that if you feed the TV an interlaced signal you're going to get both bad deinterlacing and bad scaling, as opposed to good deinterlacing (from the DVD player) followed by bad scaling. You're just doubling up your problems.
You're working under a couple of miconceptions here. First off, converting the progressive analog output of the DVD player to digital for scaling does not affect the deinterlacing of the signal. All this means is the the video signal bypasses the TV's deinterlacing chip and goes straight for the scaler. If the TV's deinterlacer is poor (as most are), this is a good thing.
This is a generalization that is largely untrue. Deinterlacing and scaling are two separate processes that each have their own potential artifacts. If the TV has a bad scaler, that doesn't negate the benefits of good deinterlacing. All it means is that if you feed the TV an interlaced signal you're going to get both bad deinterlacing and bad scaling, as opposed to good deinterlacing (from the DVD player) followed by bad scaling. You're just doubling up your problems.
Originally posted by Josh Z
Conversely, a good scaler in the TV will not fix bad deinterlacing artifacts. Deinterlacing has its own artifacts that are unrelated to scaling.
Conversely, a good scaler in the TV will not fix bad deinterlacing artifacts. Deinterlacing has its own artifacts that are unrelated to scaling.
Originally posted by Josh Z
In order to scale from 480i to 1080i, the video signal is actually deinterlaced, scaled, and then reinterlaced. If the deinterlacing step is bad, this will also trip up the scaler and you'll get a worse 1080i picture.
In order to scale from 480i to 1080i, the video signal is actually deinterlaced, scaled, and then reinterlaced. If the deinterlacing step is bad, this will also trip up the scaler and you'll get a worse 1080i picture.
Originally posted by Josh Z
If we're talking about fixed-pixel displays, the scaling step has to be done regardless of how you do the deinterlacing. If the scaling is bad, you're going to get scaling artifacts regardless of whether you do good or bad deinterlacing beforehand. But if the deinterlacing is bad, this just causes even more artifacts before you get to the scaler.
It's always in your best interest to feed the television the best quality signal that you can and have the TV do the least processing on its own that it needs to. Ideally, this means running your DVD player through a quality external scaler. Those are expensive, however, and a good place to start is at least a good progressive scan DVD player.
If we're talking about fixed-pixel displays, the scaling step has to be done regardless of how you do the deinterlacing. If the scaling is bad, you're going to get scaling artifacts regardless of whether you do good or bad deinterlacing beforehand. But if the deinterlacing is bad, this just causes even more artifacts before you get to the scaler.
It's always in your best interest to feed the television the best quality signal that you can and have the TV do the least processing on its own that it needs to. Ideally, this means running your DVD player through a quality external scaler. Those are expensive, however, and a good place to start is at least a good progressive scan DVD player.
I think we've both made our points and it will be up the the individuals to decide for themselves using their equipment.
09-25-04, 08:02 AM
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A "Normal" prog scan dvd player will output 480i/p only. One of the newer upconverting DVD players can scale the 480i dvd image to 720p/1080i and output it through DVI. The quality varies on these players, the Bravo D1 is beautifu where I hear the LG's don't do a great job. If your HDTV has no DVI the best DVD picture money can buy you will come from a properly configured PC, probably even better than all of the DVI enabled DVD players.
09-26-04, 03:11 PM
#9
DVD Talk Hero
Ok, i'm not too technical so here's another question. If DVD outputs at 480, what does a HD tv signal output as? 720? 1080?
I'm getting my new Panasonic DLP this week along with the LG DVD player. Since the Panny has only 1 DVI input, should I save that to hook up the HD decoder and use component for DVD?
I'm getting my new Panasonic DLP this week along with the LG DVD player. Since the Panny has only 1 DVI input, should I save that to hook up the HD decoder and use component for DVD?
09-26-04, 07:39 PM
#10
DVD Talk Legend
Originally posted by chipmac
Some may scale before and some after but in any case if the 480p signal is scaled then you're not seeing the original true output of the player which has been my point all along.
Some may scale before and some after but in any case if the 480p signal is scaled then you're not seeing the original true output of the player which has been my point all along.
This is a new one on me. What makes you think that the scaling isn't done on the interlaced signal? I won't argue that it isn't ever done this way but why deinterlace and than scale when you can just scale and eliminate one step?
Well except for some EDTVs there are no fixed pixel displays that show 480p native so they were never meant to be included in the discussion since they must be scaled.
09-26-04, 07:50 PM
#11
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Originally posted by Josh Z
True, but most CRT RPTVs will display a 480p image natively.
True, but most CRT RPTVs will display a 480p image natively.
09-26-04, 08:21 PM
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Most CRT based RPTVs no longer display 480p natively. I tink Mits is the last of the main big name brands that does. I believe Pioneer even stopped two years ago. Sony, Hitachi, Panasonic an Toshiba like X said all upconvert to 540p or 1080i with some only allowing 1080i.
09-27-04, 01:14 AM
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Gee, I never thought that it could be this complicated ... well, maybe I'd better state my specific problems here... I have recently bought a 29 inch TV set, Philips 29PT9420 Pixel Plus. This set has prog. scan capability for sure and certainly the pict goes way ahead my previous ordinary flat LG 21.
But... despite the nice, cool color, sharpness, etc.. it still displays jaggish image, and sometimes a little bit flickers (this flicker is not annoying though). even if I switched the pixel l plus feat. into prog. scan. BTW, my DVD player is a cheap Chinese model TCL FD60.
So, if I change with player of better quality will it display jaggish free image?
If yes, then what player you suggest compatible with this Philips set, price range under USD 250? If possible with DVD component and 5.1 output...
But... despite the nice, cool color, sharpness, etc.. it still displays jaggish image, and sometimes a little bit flickers (this flicker is not annoying though). even if I switched the pixel l plus feat. into prog. scan. BTW, my DVD player is a cheap Chinese model TCL FD60.
So, if I change with player of better quality will it display jaggish free image?
If yes, then what player you suggest compatible with this Philips set, price range under USD 250? If possible with DVD component and 5.1 output...
09-27-04, 02:14 PM
#15
DVD Talk Legend
Djangoman, the jaggies are caused by bad progressive scan deinterlacing. Yes, upgrading to a new player should help. Here's a Shootout between various player models:
http://www.hometheaterhifi.com/cgi-bin/shootout.cgi
http://www.hometheaterhifi.com/cgi-bin/shootout.cgi
