Assuming that you have one file and you want a part of it (the middle) in slow motion then you can do it this way.
Note, that I also compress the audio - VirtualDub seems to be fussy that way.
Load the file, note the video FPS and audio sample rate in the file information.
Assume 25fps and 44100, 128 stereo.
Select the first part (which will be normal speed) and click 'Audio' 'Full Compression' and choose the original compression (44100,128 etc).
'Video' 'Direct Stream Copy' and save the first part (p1).
Clear the edit, but don't move the slider.
Set the new start point for the second (slow motion part) and the end point.
'Video' 'Direct stream Copy' 'Frame rate' 'Change Frame Rate to FPS' and enter 12.5 , then beneath that in the next section, choose 'Convert to FPS' and insert 25.
At this point you could click 'Audio', select the compression again and save the new clip, but you might want to make the sound 'normal but slowed down' by selecting 'Use Advanced Filtering' 'Filters'.
Add the filters 'Input' 'Stretch' 'Ratty Pitch' and 'Output'
Click on 'Stretch' and enter '2', click on 'Ratty' and enter '2' - don't forget to compress the audio, save the new AVI and importantly, reset the video frame rate and turn off the advanced filter.
Clear the edit point again and select the third part, recompress the audio, and video direct stream copy and save it.
Close and reopen VirtualDub.
Load part 1 then append the rest.
Note:if you have saved the parts with names like p1, p2, p3, the VirtualDub will append p2 and p3 at the same time.
Save the new file with direct stream video and audio.
what you said works, thank you. But I constantly get errors trying to append saying the frame rates are different. (rediculous differences like saying one is 29.000 and the other is 29.003)
The append feature is allegedly used to join clips that had previously been split with VirtualDub - thus they would be identical as to everything (except length).
Both files may need the video recompressed with the same codec then appended.
Also note that the appended file may have a sync problem, to fix that you have to clip a couple of frames from the first file (key frame?), save it, then append the second file.
Can you expand on your solution?
Which file do you choose to modify and how do you choose the values?
Do they have audio which stays in sync - or is that relevant with these particular files.
