[Tig] 24p frame rate
bfriesen at simple.dallas.tx.us
Mon Aug 4 23:47:49 BST 2008
On Mon, 4 Aug 2008, beau tardy wrote:
> I would argue that the reason it looks ok in film is that we watch
> films projected on a large screen. Film is a mechanical medium with
> light projected thru it, whereas TV and computer monitors are
> electronic media and have light beaming at us. This fundamental
There is something else about film. Each film frame is flashed
several times. Before this trick was figured out, 24 frames per
second looked really bad.
LCD and Plasma displays are becoming quite popular. These
technologies are not capable flashing the frame several times like
film. Recent LCDs are increasing their internal update rate (e.g.
120hz) so that they can interpose frames and play other tricks to try
to make the video updates more acceptable.
It makes sense for a true digital display to be a frame store (memory)
like in a computer display card. If the content does not change, then
the memory does not need to be updated. Only parts which change need
to be updated. The whole notion of "refresh" is quite dated because
it assumes that the display medium is semi-persistent. This is true
for CRTs and DLP with a color wheel or wobbulation. Refresh should be
a function of display implementation and not part of the video stream.
The only reason why whole frames need to be sent at all is to handle
channel changes, temporary loss of signal, or when the set is first
Regardless, except for the ease of transfer to film, there is nothing
magical about a particular update rate. The most magical thing about
24P is what the 'P' signifies.
bfriesen at simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer, http://www.GraphicsMagick.org/
More information about the Tig