Opened 15 months ago

Last modified 14 months ago

#7774 new defect

ProRes Scanned Alpha omitting last run of a slice if it's length 0

Reported by: vinlai Owned by:
Priority: normal Component: avcodec
Version: git-master Keywords: prores
Cc: Blocked By:
Blocking: Reproduced by developer: no
Analyzed by developer: no


Alpha encoded using prores_ks produces slices that omits the final run of a slice if it is length 0. This is the correct behaviour for non-alpha channels, however, the termination conditions are different for alpha.

RDD36-2015: AC Coefficients

They are terminated either by a non-zero array element—a level—or by reaching the end of the array.

7.1.2 Scanned Alpha

They terminate when one of the following occurs: two consecutive array elements have different values; the end of the array is reached; or the maximum permissible run length, 2048, is achieved.

In summary, encoded Alpha should not be omitting the final run of a slice even if it is length 0.


Change History (1)

comment:1 Changed 14 months ago by cehoyos

  • Keywords prores added
  • Version changed from unspecified to git-master
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