The other day I posted about this, saying I'd done it in the past with Avidemux.
Having just seen Virtual Dub, it's got me thinking it might not have been Avidemux but some other program I used to replace a portion of the video.
IS it possible to use Virtual Dub (or Avidemux) to replace just a portion of the video on an .mpg file, leaving the audio and the run time intact?
If not those programs, is there some other freeware program out there I might be able to use to do this?
I just can't remember how it was done last time.
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Last edited by gastrof; 17th Jul 2011 at 01:29. Reason: I'm an idiot.
Virtualdub doesn't do mpg without re-encoding, so AVI Demux would be your best bet. I would take a copy of the source file first. The I would
1. Load the source file and delete everything after the point where the 50 frames will be inserted.
2. Append the new 50 frames
3. Append the original file, and from this segment, delete everything up to the point where the 50 frames ends.
You now have the video as you want it, and assuming all parts use common settings, you should be able to save in copy mode to a new file without re-encoding.
Except that at this point your audio has a big edit in the middle where the 50 frames went.
So, under the audio menu, select Main Track, and change the source to External, and choose whatever the original format was. The select the original source file.
You should now be able to save a new copy of the file with the new 50 frames replacing old footage, and a continuous audio track.
I've tried splitting the original into three pieces then appending the new 50 frames (49, actually) to the first bit, but the playback wasn't "happy". I'm having trouble getting the number of frames to match (they keep dropping to 43 on the dubbed portion) and I keep getting one or two frames of green screen.
If I converted the video to an AVI would Virtual Dub or Virtual Dub Mod allow me to replace those 49 frames? Sort of video dub them over the original? If so, what steps would I take? (Or is there other freeware that'd allow me to replace those frames or dub them in?)
I'm looking around Virtual Dub, but can't find any obvious way to dub video. All it seems to allow is cutting portions off. I know it's my inexperience...
Both virtualdub and avi demux are assemble editors. You can cut bits out, or append bits onto the end of a clip, but you can't just 'dub' over the top or insert into a clip. For that you need a non-linear editor.
There are a few free nles, but none are great. Windows Movie Maker (not Live MM), Prism or the free Pinnacle editor - can't recall the name. All will most likely insist on re-encoding
If this is SD MPEG-2 video, Cuttermaran in encoding mode can make frame accurate cuts with minimal re-encoding, and can handle more than one video file at a time. It requires de-multiplexed audio and video. It isn't a full-featured NLE but might work for what you are describing.
You're probably having difficulty with the fact of MPEG files usually have large GOPs and you can really only edit (non-encoding) on GOP I-frame boundaries.
See where the GOP boundaries lie on your clip. If, for example, GOP lengths were (consistently) 15 Frames, then you know that if you wanted to do a clean cut and not mess with length differences nor re-encoding, you'd need to cut between Frame 45 and 46 (both for the incoming AND the outgoing clip).
Another editor that can do these with MPEG2 files - Cuttermaran.
usually_quiet, you beat me to it.