How to take quality framegrabs of 1080i video?

Question

Our group has a set of high definition footage taken in 1080i (.mov) that we want to analyse by taking framegrabs.

However, since this is interlaced footage, I was told that if I grab one frame, I only get an image that's half the video's resolution. Is there a way for me to "de-interlace" the framegrab to boost its quality?

Thank you very much.

Answer 1

Using VLC, you should be able to take some very nice frameshots if you deinterlace (Tools -> Prefererences -> Video -> Video -> Deinterlacing) the video and hit Video -> Snapshot (or hit Ctrl+Alt+S).

On a Mac, the combo would be Cmd+Alt+S.

Answer 2

MPlayer can do this

MPlayer comes with a very nice and easy to use video filter that allows taking single or multiple screenshots. The syntax is simple:

Code:

mplayer -vf screenshot my_file.mp4

Simply pressing the 's' key takes a single screenshot in png format in the working directory. If you wish to take a series of screenshots you can press the 'S' key and MPlayer will keep taking screenshots until the 'S' key is pressed again. However if this is a little too straightforward for you MPlayer also can also output images in a slightly different way that has a few more options:

Code:

mplayer -nosound -frames 5 -vo png:z=9 my_file.mp4

This will output the first 5 frames of the media file in high quality png format into the working directory. Similar screenshots can be taken by using jpeg, gif89a, targa and pnm as '-vo'. How incredibly cool is that!