GNOME Bugzilla – Bug 728534
qtdemux: Parse orientation tag
Last modified: 2014-05-22 07:04:00 UTC
It seems that the private-qt-tag contains information about orientation when video are from an iPad. Even though I don't know yet how to do so, it would be nice to produce correct orientation tag. This way we could flip it using videoflip method=automatic
Sample file: https://www.dropbox.com/s/jwfiiemvjfm8sc7/Alex%20le%20matin.mov
I think the rotation here is represented by the transformation matrix of the video: matrix 65535.000000 0.000000 0.000000 0.000000 65535.000000 0.000000 568.000000 320.000000 16384.000000 Which is: -1 0 0 0 -1 0 568 320 1 x' = -x + 568 y' = -y + 320 Do we have a video meta for rotation already?
Do you have some QT doc pointer about what valid values can be put in this matrix ?
https://developer.apple.com/library/mac/documentation/quicktime/rm/moviebasics/mtediting/k-chapter/11matrixfunctions.html is a good explanation also https://developer.apple.com/library/mac/documentation/quicktime/qtff/QTFFChap2/qtff2.html look for the tkhd atom, there is where the matrix is stored
So it can be an arbitrary transformation matrix, not just rotation. *** This bug has been marked as a duplicate of bug 679522 ***