[FFmpeg-trac] #9526(avutil:closed): AV_PIX_FMT_YUV410P description incorrect

FFmpeg trac at avcodec.org
Thu Nov 25 01:16:28 EET 2021

#9526: AV_PIX_FMT_YUV410P description incorrect
             Reporter:  Anton1699   |                    Owner:  (none)
                 Type:  defect      |                   Status:  closed
             Priority:  normal      |                Component:  avutil
              Version:  git-master  |               Resolution:  invalid
             Keywords:  pixdesc     |               Blocked By:
             Blocking:              |  Reproduced by developer:  0
Analyzed by developer:  0           |
Changes (by Marton Balint):

 * status:  new => closed
 * resolution:   => invalid


 4:1:0 notation can be used for both one chroma pair per 4x2 block and one
 chroma pair per 4x4 block. However in ffmpeg AV_PIX_FMT_YUV410P means the
 latter, one chroma pair per 4x4 block.

 Even wikipedia is confused and using both terms:


 ''This notation is not valid for all combinations and has exceptions, e.g.
 4:1:0 (where the height of the region is not 2 pixels, but 4 pixels, so if
 8 bits per component are used, the media would be 9 bits per pixel) and

 but later:

 ''This ratio uses half of the vertical and one-fourth the horizontal color
 resolutions, with only one-eighth of the bandwidth of the maximum color
 resolutions used. Uncompressed video in this format with 8-bit
 quantization uses 10 bytes for every macropixel (which is 4×2 pixels).
 Some video codecs may operate at 4:1:0.5 or 4:1:0.25 as an option, so as
 to allow similar to VHS quality.''

 So log2_chroma_h is fine as is in ffmpeg.
Ticket URL: <https://trac.ffmpeg.org/ticket/9526#comment:2>
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