How to extract orientation information from videos?

Question

After surfing through tons of documentation on the web it seems that the iPhone always shoots the video at a 480x360 aspect ratio and applies a transformation matrix on the video track. (480x360 may change but its always the same for a given device)

Here is a way of modifying the ffmpeg source within a iOS project and accessing the matrix http://www.seqoy.com/correct-orientation-for-iphone-recorded-movies-with-ffmpeg/

Here is a cleaner way of finding the transformation matrix in iOS-4 How to detect (iPhone SDK) if a video file was recorded in portrait orientation, or landscape.

How can the orientation of the video be extracted in either of the options below -
- iOS 3.2
- ffmpeg (through the command line server side)
- ruby

Any help will be appreciated.

Answer 1

Since most Cameras store their rotation/orientation within the exif-metadata, i would suggest using exifttool and the a ruby wrapper gem called mini_exiftool which is actively maintained.

Install exiftool:

apt-get exiftool || brew install exiftool || port install exiftool

or use what ever package manager is available

Install mini_exiftool:

gem install mini_exiftool

Try it:

irb>
require 'mini_exiftool'
movie = MiniExiftool.new('test_movie.mov')
movie.orientation #=> 90

cheers