Demuxing every 2nd video frame

[shepherdfte]

Hi guys - complete newbie here so hi.

Don't know much about editing stuff, and I'm not getting anywhere with search. Sorry if this is a well known problem.

I have a set of DVD (vob) files which were recorded off a MULTIPLEXED VHS (from an aircraft as it happens). So there are 2 overlaid video images, one of the aircraft's display, and one of its exterrnal camera image. When I play them now they are on DVD I end up getting both images one on top of the other. I would like to "demux" it so I get 2 sets of DVD files, one for each of the aircraft's displays. Obviously I basically need to extract every other frame with some kind of sync going on. But everything I search for talks about demuxing audio from video, not 2 video streams.



Help!?

Andy

[manono]

You can't remove half the frames while demuxing. You demux the whole thing and then use a filter that takes out every other frame and reencode it. Since you'll be cutting out half the frames, in order to keep the audio synch and to keep the same DVD compliant framerate, you should probably duplicate the kept frames. AviSynth's SelectEvery command is probably best for this:

SelectEvery(2,0,0)

That says for every 2 frames take the first one and play it twice, and skip the second one:

http://avisynth.org/mediawiki/SelectEvery#SelectEvery

I don't think any of that means anything to you, but you can't expect to do hard stuff without any knowledge or experience.

[shepherdfte]

You can't remove half the frames while demuxing. You demux the whole thing and then use a filter that takes out every other frame and reencode it. Since you'll be cutting out half the frames, in order to keep the audio synch you had probably duplicate the kept frames in order to keep the same framerate. AviSynth's SelectEvery command is probably best for this:

SelectEvery(2,0,0)

That says for every 2 frames take the first one and play it twice, and skip the second one:

http://avisynth.org/mediawiki/SelectEvery#SelectEvery

I don't think any of that means anything to you, but you can't expect to do hard stuff without any knowledge or experience.

Thanks for that - it means quite a lot to me and will be very helpful. Now I know more what I'm looking to achieve. I don't know much about video editing, but hey I'm a rocket scientist, so hopefully I'll figure it.

cheers

Andy