Question:
As technology moves on in the future is it possible for us to watch are DVD's films at 24fps, the same as the cinema on both NTSC and PAL dvd's? Now I don't know all about the technology behind DVD so I may be wrong here so if I am feel free to point it out.
As I understand it both pal and NTSC DVD's are encoded at 24fps, on PAL this is is obviously played faster causing the 4% speed up and on NTSC dvd's aren't certain frames 'tagged' or something so the DVD player knows which frames to repeat for the 3:2 pulldown which then takes it up to about 30fps and causes the NTSC judder. So essentaily the info on the DVD is 24fps in some way.
Now with TV's getting better than the usc of HDTV, LCD and Plasma it is possible for TV's to display things at different resoloution, speeds, like computer moniters have been able to do for ages. So shouldn't it be possible to design TV's and DVD players with not only NTSC and PAL but also some type of film mode?. When slected the DVD player could then play the DVD back at 24fps on a TV capable of displaying it? There could even be a NTSC film mode and a PAL film mode for the different resoloutions etc.
Seeing as the info on the DVD's is already stored as 24fps this could work on all existing DVD's, the dvd player would just have to know how to read the DVD.
This would then get rid of all PAL 'speed-up' and NTSC 'judder' and give the film the way it should be. Of course the Pal films that have had the audio corrected would now be at a lower pitch but if most people don't notice it higher then they probably wouldn't notice it lower (I think pitch correction is pointless anyway as the very people who notice the correction are going to be the people who notice the problems it causes!.)
Is this at all possible or likely or am I way off in understanding how the technology could work even on a basic level?
well largely your right but there are a number of problems to overcome yet
1. Not all NTSC discs are encoded as 24fps even if they are films
2. You can't run PAL discs at 24fps and keep the digital audio stream in sync correctly
3. LCD and Plasma screens have a fixed refresh rate that all incoming signals must be shifted too (so even if the input is 24fps the output frequency of the display might be 60Hz) - My understanding might be wrong on this though
4. You'd need a committee to organize these new standards which won't be quick
Having said that if you have a CRT based system (monitor or projector) and you hook up a PC to output a 72Hz signal you should loose NTSC judder on a correctly encoded DVD
Phil
The film mode you are talking about exists - it's called Progressive Scan. This reads the 3:2 and 2:2 pulldown used in NTSC and PAL interlaced signals and reconstitutes the full image.
There are CRT, LCD and plasma displays that will run a progressive scan DVD output. Although 24 frames are output (25 in the case of PAL progressive scan), the output is actually 50/60 frames per second, only 24/25 are obviously different frames. This shouldn't be a problem though because obviously there were never more to begin with on the source film. There'd be no more judder than what you would see at the cinema.
In terms of different timing modes etc... well if you stick to NTSC progressive scan, you won't need any. PAL is a problem since it runs at 25fps, not 24fps. Obviously it would be reading in data faster than it needs it and the buffer to store 4% of a movie as you watch it would be rather large. You'd be looking at spooling the data onto a hard disc.
Far too much hassle. Just get progressive scan capable kit and stick to NTSC DVDs if the PAL PAL progressive scan has about 17% more resolution.
As Mr Badger also points out, a lot of material on DVD isn't filmed as progressive scan images, so you'd need some kind of decent deinterlacer onboard to maintain a progressive scan image - again, progressive scan DVD players already do their best to sort this out for you.
Originally posted by Grandmaster
There are CRT, LCD and plasma displays that will run a progressive scan DVD output. Although 24 frames are output (25 in the case of PAL progressive scan), the output is actually 50/60 frames per second, only 24/25 are obviously different frames. This shouldn't be a problem though because obviously there were never more to begin with on the source film. There'd be no more judder than what you would see at the cinema.
But displaying 24 frames of the film within 60 refreshes of the screen isn't possible without repeating some of the frames more than the others - and it's this that causes NTSC judder - or have I misunderstood something ?
Phil
I thought the "NTSC judder" as it's known was a result of 3:2 pulldown on interlaced sources. You know, you could be right - but I've never noticed this whatsoever on my kit. The obvious solution if this is a problem would be to invest in a scaler that can match the frequency of your monitor, or get into the whole Home Cinema PC scene in general.
I think the "problem" being discussed here is so minute and so niche that it's unlikely to bring about a massive change in display or DVD playback technology.
Most NTSC disks encoded at 24fps progrssive, most PAL DVD's encoded at 25fps.
Now you can get an output on a PC at 24fps from PAL 25fps/Progressive DVD's thats totally smooth and with the sound in sync using WinDVD 5 with the PAL TruSpeed option. If I alter my monitor to 72hz (24x3) I get smooth pans on PAL and NTSC disks. Setting the monitor to 75hz reveals a slight frame repeat. This option is the way to go if you have a Plasma or projector that will sync to the 72hz frequency. So its available now if you have a PC and Plasma/Projector.
USA Hi-Def televisions are suppose to be able to show 72hz material with a compatable resolution, so no more juddery pans for them they can also reverse the 3:2 pulldown effect and get smooth pans on current dvd's from existing dvd players.
As I understand it both pal and NTSC DVD's are encoded at 24fps, on PAL this is is obviously played faster causing the 4% speed up and on NTSC dvd's aren't certain frames 'tagged' or something so the DVD player knows which frames to repeat for the 3:2 pulldown which then takes it up to about 30fps and causes the NTSC judder. So essentaily the info on the DVD is 24fps in some way.
Now with TV's getting better than the usc of HDTV, LCD and Plasma it is possible for TV's to display things at different resoloution, speeds, like computer moniters have been able to do for ages. So shouldn't it be possible to design TV's and DVD players with not only NTSC and PAL but also some type of film mode?. When slected the DVD player could then play the DVD back at 24fps on a TV capable of displaying it? There could even be a NTSC film mode and a PAL film mode for the different resoloutions etc.
Seeing as the info on the DVD's is already stored as 24fps this could work on all existing DVD's, the dvd player would just have to know how to read the DVD.
This would then get rid of all PAL 'speed-up' and NTSC 'judder' and give the film the way it should be. Of course the Pal films that have had the audio corrected would now be at a lower pitch but if most people don't notice it higher then they probably wouldn't notice it lower (I think pitch correction is pointless anyway as the very people who notice the correction are going to be the people who notice the problems it causes!.)
Is this at all possible or likely or am I way off in understanding how the technology could work even on a basic level?
Answers:
well largely your right but there are a number of problems to overcome yet
1. Not all NTSC discs are encoded as 24fps even if they are films
2. You can't run PAL discs at 24fps and keep the digital audio stream in sync correctly
3. LCD and Plasma screens have a fixed refresh rate that all incoming signals must be shifted too (so even if the input is 24fps the output frequency of the display might be 60Hz) - My understanding might be wrong on this though
4. You'd need a committee to organize these new standards which won't be quick
Having said that if you have a CRT based system (monitor or projector) and you hook up a PC to output a 72Hz signal you should loose NTSC judder on a correctly encoded DVD
Phil
Answers:
The film mode you are talking about exists - it's called Progressive Scan. This reads the 3:2 and 2:2 pulldown used in NTSC and PAL interlaced signals and reconstitutes the full image.
There are CRT, LCD and plasma displays that will run a progressive scan DVD output. Although 24 frames are output (25 in the case of PAL progressive scan), the output is actually 50/60 frames per second, only 24/25 are obviously different frames. This shouldn't be a problem though because obviously there were never more to begin with on the source film. There'd be no more judder than what you would see at the cinema.
In terms of different timing modes etc... well if you stick to NTSC progressive scan, you won't need any. PAL is a problem since it runs at 25fps, not 24fps. Obviously it would be reading in data faster than it needs it and the buffer to store 4% of a movie as you watch it would be rather large. You'd be looking at spooling the data onto a hard disc.
Far too much hassle. Just get progressive scan capable kit and stick to NTSC DVDs if the PAL PAL progressive scan has about 17% more resolution.
As Mr Badger also points out, a lot of material on DVD isn't filmed as progressive scan images, so you'd need some kind of decent deinterlacer onboard to maintain a progressive scan image - again, progressive scan DVD players already do their best to sort this out for you.
Answers:
Originally posted by Grandmaster
There are CRT, LCD and plasma displays that will run a progressive scan DVD output. Although 24 frames are output (25 in the case of PAL progressive scan), the output is actually 50/60 frames per second, only 24/25 are obviously different frames. This shouldn't be a problem though because obviously there were never more to begin with on the source film. There'd be no more judder than what you would see at the cinema.
But displaying 24 frames of the film within 60 refreshes of the screen isn't possible without repeating some of the frames more than the others - and it's this that causes NTSC judder - or have I misunderstood something ?
Phil
Answers:
I thought the "NTSC judder" as it's known was a result of 3:2 pulldown on interlaced sources. You know, you could be right - but I've never noticed this whatsoever on my kit. The obvious solution if this is a problem would be to invest in a scaler that can match the frequency of your monitor, or get into the whole Home Cinema PC scene in general.
I think the "problem" being discussed here is so minute and so niche that it's unlikely to bring about a massive change in display or DVD playback technology.
Answers:
Most NTSC disks encoded at 24fps progrssive, most PAL DVD's encoded at 25fps.
Now you can get an output on a PC at 24fps from PAL 25fps/Progressive DVD's thats totally smooth and with the sound in sync using WinDVD 5 with the PAL TruSpeed option. If I alter my monitor to 72hz (24x3) I get smooth pans on PAL and NTSC disks. Setting the monitor to 75hz reveals a slight frame repeat. This option is the way to go if you have a Plasma or projector that will sync to the 72hz frequency. So its available now if you have a PC and Plasma/Projector.
USA Hi-Def televisions are suppose to be able to show 72hz material with a compatable resolution, so no more juddery pans for them they can also reverse the 3:2 pulldown effect and get smooth pans on current dvd's from existing dvd players.
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