I want to make an interlaced video with 50fps into a 25fps progressive, in the process i'm also reducing the size of the frame. Currently i am using avconv and there are deinterlacing options, however, they are not documented. So what i am afraid of is that they will actually start bleeding information i am trying to drop into the frames that i am trying to keep.

The only tool that i have found, that does a documented drop of even/odd frames is a plugin for AVIDemux, which unfortunately does not export into Ogg or even encode into Theora. When i attempt to dump into Huff codec (to not introduce quality loss due to reencoding) it demands that i split files at 4 GiB. So i can only use it for small videos.

Is there another tool that can help me?

  • You could always do the 4gigabyte split and then cut them back together after (assuming Huff codec supports append operations without re-encoding, I'm not familiar with that particular codec.)
    – AJ Henderson
    Commented Nov 4, 2013 at 14:15
  • @AJHenderson It is a possibility, and i was already looking at that, but it's a hack. I think i would rather try to figure out the avlib's code and create a 'drop-deinterlacer', but i was hoping that something like that already exists.
    – v010dya
    Commented Nov 4, 2013 at 14:22
  • yeah, makes sense. I unfortunately have near 0 experience with AVIDemux or avlib. I'm an Adobe/Windows guy, just a few little things when I was working on writing programs to work with video.
    – AJ Henderson
    Commented Nov 4, 2013 at 14:25

2 Answers 2


ffmpeg -i input -vf field,scale=123:456 output will do the trick, where 123:456 is your x:y frame dimensions for the output. The field filter just chucks away the fields it doesn't use. Documention on the field filter here. Note that you'll need extra stuff in the command to get good results - e.g. you'll probably want to specify codec details and so on.

  • Will give you 50 rep for this when the system permits me to.
    – v010dya
    Commented Jan 20, 2014 at 6:40

You could use ffmpeg:

ffmpeg -i input -vf framestep=2 output

This will output every second frame.

  • That doesn't actually do what is expected with the progressive video. The result is still the same vertical resolution, so it doesn't drop unneeded lines.
    – v010dya
    Commented Nov 8, 2013 at 15:51

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