| Re: YUV file format [message #6680 is a reply to message #6674] |
Tue, 30 July 1996 00:00  |
hahn
Messages: 108
Registered: November 1993
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Senior Member |
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e113@ipp-garching.mpg.de (Janpeter Wolff ) wrote:
> Hi there,
> does anybody know, if it is possible to read in Files that have the
> format .YUV? It doesn't appear in the docs, but nonetheless it would be
> nice if it were possible. Maybe someone has already added something
> to idl in this
> respect?
> Thanks,
Unfortunately there are several standards to encode YUV (NTSC, PAL,
CCIR 601). The latter is for encoding digital TV signals:
Y = 0.299 * red + 0.587 * green + 0.114 * blue
(in accordance with NTSC analogue). The color encoding differs, for
digital you can have 8:4:4 and 8:8:8. While 8:8:8 says that you use
8 bits for luminance (Y) and 8 bits for u and 8 for v the more common
encoding averages two adjacents points and encode for odd numbered
pixels 8 bits Y and 8 bits U as an average of two adjacent dots while
the even numbered pixels contail 8 bits Y and 8 bits V.
Now, U and V are derived from U = 0.713 * (red-Y) and V = 0.564 * (blue-Y)
Unfortunately I don't have test data to verify these formulas....
Hope this helps
Norbert
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