Is there a audio equivalent of Pulldown.exe?

[rapjp2001]

Hi All,

I have a theoretical question:

If I have a 25 fps video with audio included(assume it is either AVI or some non-MPEG format).

I demux the audio and video and then compress the video using CCE and so I get a resultant MPEG2 as 25fps video.

Now in order to create a DVD in Maestro, I have to have the video in 29.97 fps, so I can use Pulldown.exe to convert the m2v to a correct frame rate.

Here is the real catch -- when I try and insert the audio track in Maestro, will my audio not be slightly shorter than the video(since it has not been "stretched" to 29.97 fps).

The question I have is -- Is there some utility that is equivalent to Pulldown that causes the audio to increase in length appropraitely that makes the audio match with video and not suffer audio sync problems?

I am about to work with a 25 fps source video that I want to create a DVD from and I will use CCE for the video encoding and use the source audio as a LPCM track.

Thanks

Rajiv

[REECYCUP]

im new to the audio thing but:
if your movie is the same lenth in time
why increase the audio lenth in time?

[slk001]

Pulldown doesn't "stretch" the video - it adds FRAMES to bring the fps to 29.97fps. The pre-pulldown time and the post-pulldown time will not change. Let me repeat that last statement - THE PRE-PULLDOWN AND THE POST-PULLDOWN TIME WILL NOT CHANGE. Therefore, there is no need to do anything to your audio.

The big question that I have, is why are you applying a pulldown to a 25fps movie? That sounds very suspiciously like a "PAL" movie source at 25fps, which is a valid DVD frame rate.

I suppose that you could apply a type of pulldown to your 25fps video to get it to 29.97 (30) fps, but the program named PULLDOWN.EXE is not designed to do this (only from 23.976fps). Remember, all pulldown does is insert "repeat field" flags into your original video and change the displayed fps.

[rapjp2001]

Originally posted by slk001
Pulldown doesn't "stretch" the video - it adds FRAMES to bring the fps to 29.97fps. The pre-pulldown time and the post-pulldown time will not change. Let me repeat that last statement - THE PRE-PULLDOWN AND THE POST-PULLDOWN TIME WILL NOT CHANGE. Therefore, there is no need to do anything to your audio.

Good point! I had not thought of it that way, then I need not worry as the audio will be syched with video and no "stretching" of audio needs to take place for the higher frame rate(during playback) of the video.


The big question that I have, is why are you applying a pulldown to a 25fps movie? That sounds very suspiciously like a "PAL" movie source at 25fps, which is a valid DVD frame rate.

Its unfortunately a QT mov file that is in a 320x240 resolution and at 25 fps. It is a rare concert footage that I cannot get in any other format, so I am trying to get maximum mileage out of what I have by converting it to a NTSC DVD.

Rajiv

[jdobbs]

Search for "Converting PAL to NTSC" and you'll find a lot of writeups on this. You can do it with AVISYNTH.