AVS Forum banner
Status
Not open for further replies.
1 - 20 of 38 Posts

·
Registered
Joined
·
4,040 Posts
Discussion Starter · #1 ·
We know normal film (movie) shot at 24fps. When converting to PAL the picture (and sound) is speeded up to 25fps.


Is it possible to slow down the frame rate back to the correct 24fps during playback?


Many new video processor and scaler include ananlog/digital audio processing (input) so that can be taking care of too.


Is (will) there be a video processor/scaler with this feature?


regards,


Li On
 

·
Registered
Joined
·
2,951 Posts
It'd be cool to do, but there isn't anything outside the broadcasting industry capable of it.


Prehaps you could suggest to someone in the industry to make such a box. Something that, when it detects a 50Hz signal, would slow the speed down of either the video, or both the audio and video, or nothing (as some stuff is pitch corrected, and some isn't, and not all PAL material is 24P sourced), and pass through 60Hz signals. It'll need to be genlocked.


It, theoretically anyway, shouldn't be that hard to make something like that if you have the tools available to you.
 

·
Registered
Joined
·
8,317 Posts
Let's say you play a 2 hour movie with 25fps movie from a DVD player. When playing it with 24fps the film will be 5 minutes longer. That means the DVD player is done with playing 5 minutes before you stop watching. So for a 2 hour movie the video processor would have to keep 5 minutes of video plus audio in its memory. For a 3 hour movie it's already 7.5 minutes. Current video processor can't possibly do that, cause they simply don't have enough memory. You'd need a video processor with a harddisk or something like that to make it work.
 

·
Registered
Joined
·
4,040 Posts
Discussion Starter · #4 ·
Haven't thought of that! :D


So basically PAL is screwed! Too bad they keep using 50Hz in HDTV format!


regards,


Li On
 

·
Registered
Joined
·
8,317 Posts
Quote:
Originally Posted by Li On
Haven't thought of that! :D


So basically PAL is screwed! Too bad they keep using 50Hz in HDTV format!
We can't possibly change the refresh rate here in Germany! Look, all older TVs can only do 50Hz, not 60Hz. If the production would be changed to 60Hz now, the new production streams would be incompatible with the older TVs!


But I don't get why you say that PAL is screwed? Actually the Panasonic plasma handles it quite nicely. It runs PAL sources in 100Hz without any problems. The only current problem is that you can't feed in native resolution with 50Hz into the Panasonic, which will hopefully change sooner or later.


Actually I think 50i is better than 60i for movies, cause 60i introduces motion judder (3:2), while 50i is straight (2:2). Here in Europe we don't even know what motion judder is!
 

·
Registered
Joined
·
4,040 Posts
Discussion Starter · #6 ·
I meant the 24fps->25fps speedup.


IMO they should dump the 50Hz in HDTV format and screw all current 50Hz only SDTV! They need a better TV for HDTV anyway! :D


regards,


Li On
 

·
Registered
Joined
·
8,317 Posts
Well, a lot of people here already complain that the soccer world cup 2006 will be sent in 16:9 format. They don't want to have black bars on their old 4:3 SD CRTs!


Fortunately we'll finally be getting HDTV here soon (we don't have it yet!). Bout time!! On the positive side of things: We're late, but we'll start with H.264 broadcasts from the beginning. No lousy MPEG2 for HDTV broadcasts here!


:D
 

·
Registered
Joined
·
2,951 Posts
Quote:
Originally Posted by madshi
We can't possibly change the refresh rate here in Germany! Look, all older TVs can only do 50Hz, not 60Hz. If the production would be changed to 60Hz now, the new production streams would be incompatible with the older TVs!


But I don't get why you say that PAL is screwed? Actually the Panasonic plasma handles it quite nicely. It runs PAL sources in 100Hz without any problems. The only current problem is that you can't feed in native resolution with 50Hz into the Panasonic, which will hopefully change sooner or later.


Actually I think 50i is better than 60i for movies, cause 60i introduces motion judder (3:2), while 50i is straight (2:2). Here in Europe we don't even know what motion judder is!
I think the idea was to convert it to 24p, and then do 2:2 or 3:3 pulldown to 48Hz/72Hz, so no motion judder.
 

·
Registered
Joined
·
8,317 Posts
Sure, Carled, that's the way to do it in NTSC land. However, not all displays support 72Hz. In fact very few do, I think. So to not have motion judder for movies in NTSC land is quite difficult. In PAL land we *never* have motion judder, except maybe when trying to watch 60Hz video stuff (which is rather rare).
 

·
Registered
Joined
·
2,951 Posts
Quote:
Originally Posted by madshi
Sure, Carled, that's the way to do it in NTSC land. However, not all displays support 72Hz.
CRTs and the Qualia 004 do anyway.

Quote:
In PAL land we *never* have motion judder, except maybe when trying to watch 60Hz video stuff (which is rather rare).
You get it on stuff that was frame rate converted from 60fps.
 

·
Registered
Joined
·
8,317 Posts
Quote:
Originally Posted by Carled
CRTs and the Qualia 004 do anyway.
Unfortunately neither Pany nor Fujitsu plasmas do that, afaik... :(

Quote:
Originally Posted by Carled
You get it on stuff that was frame rate converted from 60fps.
True, although it depends very much on the quality of the conversion. Some conversions are awful, on others you don't notice any judder at all (don't know how they did that!).
 

·
Registered
Joined
·
2,951 Posts
Quote:
Originally Posted by madshi
on others you don't notice any judder at all (don't know how they did that!).
Blended frames.


They're fine until you push the pause button. Then it looks like someone has vomited on your screen.



Life's full of compromises...
 

·
Registered
Joined
·
8,317 Posts
Quote:
Originally Posted by Carled
Then it looks like someone has vomited on your screen.
:D


Can any video processor on the market do blended frames in realtime?
 

·
Registered
Joined
·
2,951 Posts
Quote:
Originally Posted by madshi
Can any video processor on the market do blended frames in realtime?
The Snell & Wilcox unit is pretty good at it. The cheaper you go, the nastier it gets, of course.
 

·
Registered
Joined
·
28,096 Posts
WinDVD has a function called "PAL TrueSpeed" that is supposed to slow down PAL discs to 24fps speed. To my knowledge, there are no standalone DVD players or video processors with a similar feature.
 

·
Registered
Joined
·
4,644 Posts
Quote:
Originally Posted by Josh Z
WinDVD has a function called "PAL TrueSpeed" that is supposed to slow down PAL discs to 24fps speed. To my knowledge, there are no standalone DVD players or video processors with a similar feature.
What does WinDVD do to the audio track?

Does it decode, resample, adjust the pitch, and then re-encode, all in realtime?
 

·
Registered
Joined
·
28,096 Posts
Quote:
Originally Posted by Erik Garci
What does WinDVD do to the audio track?

Does it decode, resample, adjust the pitch, and then re-encode, all in realtime?
I'm pretty sure it just slows it down without adjusting the pitch. I personally don't use the feature.
 

·
Registered
Joined
·
1,005 Posts
Quote:
Originally Posted by Li On
So basically PAL is screwed! Too bad they keep using 50Hz in HDTV format!
Who told you that? What's out now in europe is nothing but test transmissions and a few rare movies every couple of months and those are dubbed anyway so it's not worth watching to me.


The simple truth is, we'll have several HD stations by the end of the year (movies, sports, events) and they'll show whatever format they get their stuff in. So the formats used will be either 1080i50, 1080i60 or 1080p24sf.



Quote:
Originally Posted by madshi
We can't possibly change the refresh rate here in Germany! Look, all older TVs can only do 50Hz, not 60Hz.
That's not true. Basically every TV sold in the last 15 years or so will do 50Hz and 60Hz without a problem. What those old TVs won't do is NTSC, so you'll end up with B&W picture. 60Hz is no problem at all.


Quote:
Originally Posted by madshi
No lousy MPEG2 for HDTV broadcasts here!
That would be a good thing if it wasn't for the fact that MPEG2 still looks better than H.264. You can see this in scenes with alot of movement, like rain and so on. MPEG2 still performs better here.


The reason they jump on H.264 now instead of waiting for the codec to improve is rather simple. You need alot less bandwidth because the compression is better. So in the end, why broadcast one channel with MPEG2 if you can broadcast 3 or 4 channels in H.264 for the same cost, even if it doesn't look as good?


I'm not really impressed by the H.264 test broadcasts, my HD material from the US and Japan looks way better than this. Of course this is not the case with all material as there always is good and bad HD video.



You're right about the judder. Personally I'd rather have 60Hz and convert it to a 24fps based format (48Hz, 72Hz, 1080p24sf, ...) than live with the awful PAL-speedup. Keep in mind you're not just speeding up the video which can look bad, but also the audio. I'm sensitive to this and can usually hear it. Very few transfers are actually pitch corrected.
 

·
Registered
Joined
·
8,317 Posts
Quote:
Originally Posted by Stephan
That's not true. Basically every TV sold in the last 15 years or so will do 50Hz and 60Hz without a problem. What those old TVs won't do is NTSC, so you'll end up with B&W picture. 60Hz is no problem at all.
Oh, I didn't know that. Thanks for the information!

Quote:
Originally Posted by Stephan
You're right about the judder. Personally I'd rather have 60Hz and convert it to a 24fps based format (48Hz, 72Hz, 1080p24sf, ...) than live with the awful PAL-speedup. Keep in mind you're not just speeding up the video which can look bad, but also the audio. I'm sensitive to this and can usually hear it. Very few transfers are actually pitch corrected.
Some weeks ago I downloaded a "Full House" episode in english and was *shocked* to hear that the titel song is deeper and slower in the original!
 

·
Registered
Joined
·
610 Posts
Quote:
Originally Posted by Stephan
You're right about the judder. Personally I'd rather have 60Hz and convert it to a 24fps based format (48Hz, 72Hz, 1080p24sf, ...) than live with the awful PAL-speedup. Keep in mind you're not just speeding up the video which can look bad, but also the audio. I'm sensitive to this and can usually hear it. Very few transfers are actually pitch corrected.


is there a list of pitch corrected PAL transfers ?


thanks


Michael
 
1 - 20 of 38 Posts
Status
Not open for further replies.
Top