[FFmpeg-trac] #9598(ffprobe:new): Wrong Chroma Location (Type 2, top left) for XDCAM Files (Type 0, left) in FFProbe

[FFmpeg]

#9598: Wrong Chroma Location (Type 2, top left) for XDCAM Files (Type 0, left) in
FFProbe
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             Reporter:  FranceBB     |                    Owner:  (none)
                 Type:  defect       |                   Status:  new
             Priority:  normal       |                Component:  ffprobe
              Version:  git-master   |               Resolution:
             Keywords:               |               Blocked By:
  ChromaLocation                     |
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
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Comment (by FranceBB):

 That's alright, but the thing is that I think XDCAM-50 is using Type 0,
 left. There isn't any reason why MPEG2 yv16 (4:2:2) shouldn't be using the
 MPEG2 chroma placement, so Type 0, left, so I don't think the value
 reported by FFProbe is right at all. Same goes for FFVideoSource and
 LWLibavVideoSource.

 Just to align everyone, the discussion on Doom9 was:

 '''Ferenc Pinter:''' Topleft is treated as invalid for 422, it's accepted
 only for 420

 '''Dogway:''' looks MPEG2 to me

 (he's referring to the MPEG2 Type 0 left chroma placement of the sample
 clip I posted, therefore confirming that FFProbe got it WRONG, just like
 ffms2 and LSMASH).

 '''Reel.Deel:''' I was under the impression that 4:2:2 has always had a
 "left" (type 0) chroma location. My understanding is that the "left"
 chroma location was introduced in MPEG2, before then it was only centered
 since that was the spec on MPEG1. Also, it would not make much sense for
 4:2:2 to be top left since the chroma has full vertical resolution. If
 that were to be the case it would mean shifting the chroma half a pixel
 down when converting to RGB, for no good reason. I've never seen any
 illustration/articles that show/mention a different chroma placement for
 4:2:2.



 ..........

 So, that being said, I'm under this impression too, 4:2:2 has always had
 left, type 0, MPEG-2 chroma placement, especially on MPEG-2 Streams like
 XDCAM-50 is!

 We all seem to agree that FFProbe, LWLibavVideoSource and FFVideoSource
 all report the WRONG chroma location as it shouldn't be top left at all,
 but rather "left" and that's a bug and needs to be fixed.
-- 
Ticket URL: <https://trac.ffmpeg.org/ticket/9598#comment:5>
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