25, 29.97 or 30fps??? Thats it?????

greenspun.com : LUSENET : Video CD : One Thread

Ok, I'm using VirtualDub and DVMPEG in conjunction to go straight from .asf format to .mpg. But what's with the frames per second?? I have some info that tells me I can't make a VCD with and other frame rate but 25, 29.97 or 30fps. Is there a why to modify the fps rate without desyching the sound??? Thx


-- Benny B. (benhams4@msn.com), December 19, 1999


VCDs follow the mpeg-1 White Book standard prescribed by Philips that restricts frame rates to any of the three: 25, 29.97, and 23.976. You can't, and are not allowed to make a VCD with frame rates other than those. If you manage to do so that is NOT a legit VCD and therefore may or may not play on standard set-tops if that was your aim. This is why even before capturing video it's always important to think about what your intended final target format is, and if it's going to be VCD things get much simpler if capture is done at any of these three prescribed frame rates. In DVMPEG itself there is an applet that allows frame rate conversions without altering anything else. When you do this, however, you also have to alter the h/w to match that of your desired framerate: 25fps is 352x288, and 23.976/29.97fps is 352x240. A similar converter is also available from http://www.inmatrix.com that allows such to be performed in the .avi domain (before conversion .mpg).

-- EMartinez (epmartinez@hotmail.com), December 19, 1999.

Where in DVMPEG is this applet?

-- Benny B. (benhams4@msn.com), December 19, 1999.

And also, if I have a movie file, lets say its at 15fps, how can I change that to another rate without desycnching the sound stream?

-- Benny B. (benhams4@msn.com), December 19, 1999.

Moderation questions? read the FAQ