What is 24p?

Many cameras that have the ability to shoot in 24p mode do not actually store the footage at this frame rate. We have found this to be the case for the Canon AVCHD range of cameras.

When shooting in 24p mode they will capture 24 full frames per second, but then actually store the footage in 60i (i.e. NTSC which is 29.97 frames per second, interlaced) format into the video file.

This process is known as telecine and can be done several different ways. Commonly it is achieved by splitting the full frames (progressive) into interlaced pairs and periodically repeating a frame to increase the frames per second from 24 to 60. The is known as 3:2 pulldown, as 2 progressive frames are split into 5 interlaced frames. For example two full frames (A and B) are encoded as A1:A2:B1:B2:B2, where A1 is the first interlaced half of frame A, A2 is the second interlaced half of frame A and so on.

It is possible to perform the inverse operation (inverse telecine) and retrieve the original 24p footage.

VoltaicHD can perform a inverse telecine pulldown to restore the original 24p movie from the recorded 60i movie.

VoltaicHD can also preserve the 60i movie and create a 60i output movie.