[Ffmpeg-devel] ffmpeg & postprocess_internal.h (colorspace issue)
Mon Jul 25 10:34:18 CEST 2005
Kris A. Wotipka wrote:
>> AFAIK this means yuv420p colorspace, but with the standard luma range
> To be honest, this line really helped me because it put me on the track
> of YUV.
Actually, (almost) all digital video codecs use the YUV colour space.
Reason being that it decorrelates the RGB components, and you can reduce
the bandwidth for the U and V components because the human visual system
isn't as sensitive to colour changes as it is to luminance changes.
BTW, if you're trying to learn about digital video, take a look at Mike
> No one had ever suggested that I need to take this route
> before. I am wondering if the "p" is for "Progressive" or "PAL". If I
> remember right, it was decoding in the PAL format when I used it.
The "P" stands for "Planar", as Michael pointed out... it means that the
video frame is laid out in memory such that you first have the Y
component for the whole image, followed by the U and V components. The
alternative would be "packed pixel"... meaning that you first have the
Y, U and V components for the first pixel, then the YUV for the second
pixel, and so on. (More or less... it gets a bit more complicated if you
have chroma subsampling.)
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