[FFmpeg-trac] #4417(avcodec:new): v210 is lossy with values below 0x00000001

[FFmpeg]

#4417: v210 is lossy with values below 0x00000001
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             Reporter:  dericed     |                    Owner:
                 Type:  defect      |                   Status:  new
             Priority:  normal      |                Component:  avcodec
              Version:  git-master  |               Resolution:
             Keywords:  v210        |               Blocked By:
             Blocking:              |  Reproduced by developer:  0
Analyzed by developer:  0           |
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Comment (by kierank):

 Hi Dave,

 This is described in the Apple spec:
 https://developer.apple.com/library/mac/technotes/tn2162/_index.html#//apple_ref/doc/uid/DTS40013070-CH1-TNTAG8-V210__4_2_2_COMPRESSION_TYPE

 "This compression type uses scheme B ("Video-Range" Mapping with Unsigned
 Y´, Offset Binary Cb, Cr) to get from EY´, ECb, and ECr to Y´, Cb, and
 Cr."

 "Certain Y´, Cb, and Cr component values v are reserved as synchronization
 signals and must not appear in a buffer:

 ...

 For n=8 bits, these are values 0 and 255. For n=10 bits, these are values
 0, 1, 2, 3, 1020, 1021, 1022, and 1023. The writer of a QuickTime image is
 responsible for omitting these values. The reader of a QuickTime image may
 assume that they are not present."

 Therefore the code doesn't allow these values.

 Kieran

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Ticket URL: <https://trac.ffmpeg.org/ticket/4417#comment:2>
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