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Frame rates and maximum image size
Background: I'm researching all elements involved in transferring 16mm film (24 frames per second) to DVD, including audio.
First, I was curious to see how DVDs handled the 24fps original rate of movies initially recorded on film. So I played a DVD of an older movie and counted the frames that appeared in each second (playing at 1/16th speed, of course). It gave a consistent 24fps. (A VCR playing a tape gives a consistent 30fps.) This impressed me, as it indicated that no changes need to be made to the frame rate I receive from the film (well, except for concerns about audio and the recommended "29.97fps" rate, but that's another topic).
So I wanted to see if I had any DVDs of modern films that had been shot directly to digital, which I assumed would be 30fps to comply to NTSC television standard. I tried "The Italian Job," and discovered that the frame rate varied from scene to scene. In one instance, it alternated between to camera angles in one scene, and the frame rate changed from 30fps to 10fps (yikes!) depending on which camera was used. I believe that this is a form of video compression, where high (24-30fps) rates are reserved for fast action and low rates (down to 10fps, apparently) are used for largely static shots.
Now, the movie I want to convert to DVD is only about 31 minutes in length. Since it's coming from film stock, and I'll be scanning each frame directly, I should have some flexibility in choosing the resolution of each image that will make up the video.
I imagine that DVD has some flexibility with image sizes, just as it does with frame rates, to accomodated different sources (VHS, laserdisc, other DVDs, etc.). So is there a "hard" maximum to the size of the video image, or is it simply an effective maximum, beyond which the machine can't decode or display the video rapidly enough? The idea here is that for a short movie, I would prefer to use the capacity of the DVD for extra video quality. It won't make a difference on a TV, but 1024x768 video would look amazing on a monitor, if it's possible to achieve.
Any thoughts on this (or corrections on my statements/assumptions) would be appreciated. (If anyone can provide a link to an existing website which deals with this, that would be great.)
First, I was curious to see how DVDs handled the 24fps original rate of movies initially recorded on film. So I played a DVD of an older movie and counted the frames that appeared in each second (playing at 1/16th speed, of course). It gave a consistent 24fps. (A VCR playing a tape gives a consistent 30fps.) This impressed me, as it indicated that no changes need to be made to the frame rate I receive from the film (well, except for concerns about audio and the recommended "29.97fps" rate, but that's another topic).
So I wanted to see if I had any DVDs of modern films that had been shot directly to digital, which I assumed would be 30fps to comply to NTSC television standard. I tried "The Italian Job," and discovered that the frame rate varied from scene to scene. In one instance, it alternated between to camera angles in one scene, and the frame rate changed from 30fps to 10fps (yikes!) depending on which camera was used. I believe that this is a form of video compression, where high (24-30fps) rates are reserved for fast action and low rates (down to 10fps, apparently) are used for largely static shots.
Now, the movie I want to convert to DVD is only about 31 minutes in length. Since it's coming from film stock, and I'll be scanning each frame directly, I should have some flexibility in choosing the resolution of each image that will make up the video.
I imagine that DVD has some flexibility with image sizes, just as it does with frame rates, to accomodated different sources (VHS, laserdisc, other DVDs, etc.). So is there a "hard" maximum to the size of the video image, or is it simply an effective maximum, beyond which the machine can't decode or display the video rapidly enough? The idea here is that for a short movie, I would prefer to use the capacity of the DVD for extra video quality. It won't make a difference on a TV, but 1024x768 video would look amazing on a monitor, if it's possible to achieve.
Any thoughts on this (or corrections on my statements/assumptions) would be appreciated. (If anyone can provide a link to an existing website which deals with this, that would be great.)
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