[MPlayer-dev-eng] help request: YUV fourcc internals

[Nick Kurshev]

Hello, Arpi!

On Fri, 23 Nov 2001 12:22:43 +0200 (CEST) you wrote:

> Hi,
> 
> > As I've found (looking at radeon sources from X11 and gatos stuffs):
> > YUY2 is flat format - it has only one image surface with interlaved
> > YUYV components (and indeed it's VYUY422 format).
> yes, YUY2 and UYVY are packed (interleaved) YUV 4:2:2 formats
> 
> > Well, but IYUV, YV12, I420 are complex formats and consist from 3 parts:
> > 
> > +------------+
> > |            |
> > |     P1     |
> > |            |
> > +------------+
> > | P2  |  P3  |
> > +------------+
> yes.
> 
> > As I've found only difference between I420 and YV12 it's swapped P2 and P3
> yes.
> 
> > parts. And as I understand: IYUV === YUV12, isn't?
> no. IYUV == I420 == swappedUV(YV12)
> 
> > But what is difference between YUV12 and YV12?
> YV12 is the fourcc of YUV12. there is no format called YUV12 in this world.
> in tech stuff call it planar 4:2:0, the codecs call it YV12
> 
> > >From name it's understandable that YV12 lacks U-component,
> > then what is instead?
> no.
> 
> > P.S.: IMHO it would be better to add such info into main/DOCS/tech/fourcc.txt
> > same as describe - what codec are able to produce rare outputs.
> > (Currently I'm interesting with I420, YUV12, YVYU422, YUV09, and many other
> > from img_format.h)
> ok. later. or do it. :)
> 
Thanks - 've understand my probs.
It works in similar to FOURC_Y800, i.e. lose U and V planes
so I get grayscale output on YV12 formats
> 
> A'rpi / Astral & ESP-team
> 
> --
> mailto:arpi at thot.banki.hu
> http://esp-team.scene.hu
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> 


Best regards! Nick