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Discussion Starter · #1 ·
I have done a bit of a search and haven't come up with what I wanted to know. What is the difference between film and video. I ask this as I have a Sony 1252 and have been playing around with my PC with it, and I just don't know what refresh rate to setup power strip at. I am from Australia so I watch some PAL and mostly NTSC DVD's. So what is the best refresh rate for me, or do I need two different rates, one for PAL and one for NTSC.

Alot of the post's talk about film and video and I don't know the difference.



Also any recommendations on resolution to run this projector at. At the moment the computer lives in the computer room and I only play around with it on the projector sometimes (the wife hates tinkering, I love it) I think the picture looks fairly good at 480i, so any improvement will be fantastic. HTPC when the WAF is high. Very very very low WAF at the moment.


Thanks to all the people in the know.:D :D :D
 

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Biggest difference between film and video in this forum, aside from many saying film is better than video, is that film is shot and run at 24 frames per second, while video is shot at 30 frames per second for NTSC and 25 frames per second for PAL. (Actually a little bit lower, like 23.93 for film, 29.91 for NSTC, etc.)


When a film (movie) is transferred to video for NTSC, they do this little trick where the film frame is shown, then 1/2 of the frame is shown, combined with the next frame. Its called 3:2 pulldown... or maybe that's the process to remove it. I forget. :) When a movie is transferred to PAL, they just play the video back a little faster than the audio track, resulting in a little lip sync problems.


Most folks with CRT projectors love to use 3:2 pulldown systems to remove the extra frames from their NTSC DVDs, videos and laserdiscs, allowing them to watch the movie at its original 24 fps, resulting in smoother motion.


I only use NTSC sources, and I have two refresh rates: 48 Hz to run 24 fps "film" (every frame gets shown twice), and 60 Hz to run 30 fps "video" (every frame gets shown twice). Sometimes TV programs are shot originally on 24 fps filem, then converted to 30 fps video for broadcast, so I'll even watch some TV shows at 48 Hz, because they look better. Some TV shows though are only shot at 30 fps, and running them at 48 Hz looks horrible.


If you want NTSC and PAL, you might want 3 or 4 refresh rates, to get film and video for each region.


HTPCs are great. :) Especially if your projector can handle at least 480p... or better. If you can get a true progressive image from a film source at 48 Hz, it should look pretty good. I'm still quite the noob at this stuff, and I've got nice 3d images jumping off my screen with pretty fluid motion at 720p 48Hz... gotta love the HTPC.
 

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Discussion Starter · #3 ·
But I guess the question still reamins, how do I know the difference between watching film and video? So that I can setup powerstrip before I start to watch the dvd, so that it's not all jumpy (my wife hates it when I stuff around with stuf when where watching a movie
 

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If you're going to use Powerstrip to do this you might want to be aware of a limitation that it currently has. Here's a thread that I started a few days ago - it has the problem and the current solutions.


Andy.
 

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Yea, that's a quite well known problem with PowerStrip on the forum, I'm sure you can find my thread asking the very same question back in September or something. And getting the same answer from everyone. (/t:)


I also asked "how do you know". Truth is, you don't. If you know where the source is from, you just "know". For example, I know that the movie "Star Wars II: Attack of the Clones" was in the theaters, and therefore on film, and therefore is a 24fps source. Meanwhile some PBS/BBC special is most likely 30fps video source because it wasn't in theaters.


A reasonable general rule is: shown in local cinema at some point: 24fps source. otherwise: who knows. :D For the latter, try it at 24 fps, if it jutters bad, try 30 fps. I don't have any suggestions for the PAL sources, nor do I know what a PAL disc at 48 Hz would look like. Usually I see the jutter within the first 5 minutes of watching something and correct for it in a few seconds.


DScaler will tell you if it currently is seeing a 3:2 cadence and is correcting for it in its status bar. If you go full screen, you can look at the OSD screens to get that information. This might require enabling all 5 OSD screens, as not all are enabled by default.


TheaterTek 1.5 now finally will tell you the frame rate in the information OSD. (Use "I" not Ctrl-I.) Prior versions could not do this. Other DVD player applications may vary.


The good news is, if you just want to change the refresh rate while your watching a show or DVD, DScaler and TheaterTek will let you change the refresh rate while they are running. Just arrange for Girder to run PowerStrip command line in the background, running "Hidden". I have two remote keys setup, "48Hz" and "60Hz" and can jump back and forth. Sure there's a stutter as my Barco switches and syncs, but once its switched its steady. I usually only switch if I know I'll be at that refresh rate for at least 15 minutes, and the current one looks horrible.


I was pretty worried about getting the right rates too when I first started. Turns out, after a while, you'll quickly see what the 4 different possibilities looks like (well, for NTSC only) and can pretty much judge what the source is based on where it came from, and what it looks like on the current refresh rate. :D


Does this make any sense?


As for the WAF, two things: one, put the movie in BEFORE showtime, twiddle, and THEN invite her into the room. two: hide the remotes on yourself. Or better, offer her custody of them during the movie.


I had a horrible twiddle finger reflex when I first got things setup. Kept playing with every control possible on the projector, or the HTPC. My wife whined, bitched, etc. Once I got things settled (or maybe it was me that settled), I only use the remote to power up the projector, and to power it down. She is much happier now. And I no longer have to offer her the remotes.


I only have to twiddle now for the odd DVD like "The Rock" which appears on my screen shifted right about 40 inches... and she accepts the 5 seconds it takes for me to correct it in TheaterTek's aspect ratio editor. TheaterTek is great because it will remember the correction on a per disk basis, so the next time we watch it the correction is not necessary.
 

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Discussion Starter · #6 ·
Spearce


Thanks for your reply, and taking the time to explain it.


Down here in OZ we can buy houses pretty cheep, so my wife and I have two (we are only 24). Our new house that we are about to move into (have been renting it out) has a games room that will be the dedicated home theater room its 14.8 feet by 18.1 feet so should make a good room for this.


The reason that I posted in the first place was that when I connected my computer up to the projector. It didn't seem to matter what refresh rate I was running the image was always jumpy (it's a 1Ghz Processor) if only a little bit. I don't have DScaler yet, is this the reason that its jumpy. Because of the 3:2 pull down you mentioned or would it be something else.


Thanks again for your time in replying.
 

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Lucky you guys living in OZ... :D We're still renting. Of course, we may not settle in this area long enough to make buying a house (and moving it into) really worth the time, effort and money...


What is your source? External DVD player through a video capture card? Have you tried a pure software DVD player yet? If your are using a video capture card, get DScaler ( http://www.dscaler.org/ ). Its free. And it rocks. I'd still prefer a software DVD player over an external player with DScaler however.


I've found the image will stutter if PowerStrip isn't set exactly to the proper refresh rate. For example, NTSC isn't really 60 Hz, its 59.94 Hz. At 59.95 Hz you can see stutter that goes away at 59.94 Hz. Or at least I do... or at least I think I do. :D


So if your using PowerStrip make sure your refresh rate is exactly what its supposed to be for your video, close approximations like we often state as 48 Hz, 50 Hz, 60 Hz etc. aren't close enough when it comes to setting up PowerStrip.


You really won't get good video until you get PowerStrip setup properly on your PC. At $30, its a steal for what it does, and is in my opinion (which counts for nothing) perhaps the second most important part of an HTPC (the first being the video card itself).


How are you connecting your PC to your Sony pj? RGB breakout cable? Will it accept the sync format you are using, or is it just dealing with it? What resolution are you running on the PC?


You might want to read the HTPC Forum that is also hosted here, there's a lot of folks on that forum that can help you get everything setup properly... including some of us CRT folks who love 48 Hz for movies. :) I know there are some others from OZ in there, and definately folks who watch both PAL and NTSC material on their CRT sytems.
 

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A 1 GHz P-III is more than fast enough for both DScaler and pure software DVD player, but its best if you can get hardware assist from an ATI Radeon video card. :D I love my ATI. I'll love an MP-1 even more when I get around to ordering it. :D


I think your "jumpy" problem is just bad refresh rate configuration and player software configuration. I think if you can get them setup properly, things will look great.


I'm wondering what you mean by "jumpy" though, as I'd say a dropped frame effect is "stutter", while "jumpy" is the image is not stable within the raster and is shaking vertically or horizontally...
 

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Discussion Starter · #9 ·
Yes it's definatley stutter, not jumpy (so many terms to get use to)


As I don't use the computer in the home theater yet (just playing around first) I haven't had time to check if precise refresh rates fix my problem.


Thanks spearce for your help and time with your helpful explanations.
 
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