I have many small Quicktime *.mov movies ( 1 min maximum playing
time), showing drops of some liquid falling into a glass filled
with that liquid and the like.
Now, I’d like to extract a sequence of snapshot images taken at defined
times from such a movie. These snapshots should be in some graphic
format which I could open with Imagemagick/Rmagick
to access individual pixels and see how their colour evolves over time.
(The latter is not a problem).
I have many small Quicktime *.mov movies ( 1 min maximum playing
time), showing drops of some liquid falling into a glass filled
with that liquid and the like.
Now, I’d like to extract a sequence of snapshot images taken at defined
times from such a movie. These snapshots should be in some graphic format which I could open with Imagemagick/Rmagick
to access individual pixels and see how their colour evolves over time. (The latter is not a problem).
How could this extraction be done?
Apparently transcode can do this:
If you are on a MAC, iMovie will do this. Import the clips, and then
File > Export > Compress Movie for Expert Settings and then later choose
“Movie to Picture”.
From that perspective, even Quicktime Pro can do it. And it’s
scriptable via Ruby (through AppleScript)
You don’t even need the paid version of Quicktime Player as its
scripting interface is fully accessible even in unpaid mode. Another
Mac-only option would be to use QTKit via RubyCocoa. I dunno what’d be
best option in this case though as it’s not something I’ve ever done
myself.
BTW, there was a similar question here a while back - I posted a QTP-
based solution to that that might be of some help if you go that
route:
In theory, you should be able to call QTP’s ‘export’ command with the
‘image sequence’ option, but I’m not sure how you’re meant to specify
the export settings (specifically the frame rate) for that - it looks
like it may have cut a few corners there. However, if you don’t need
to export a huge number of frames, I imagine you could get by with
exporting them one at a time.