The pixel format is "pseudo-paletted". This means that it contains a
fixed palette in the 2nd plane but the palette is fixed/constant for each
PIX_FMT. This allows interpreting the data as if it was PAL8, which can
in some cases be simpler. Or the data can be interpreted purely based on
the pixel format without using the palette.
An example of a pseudo-paletted format is AV_PIX_FMT_GRAY8
@deprecated This flag is deprecated, and will be removed. When it is removed,
the extra palette allocation in AVFrame.data[1] is removed as well. Only
actual paletted formats (as indicated by AV_PIX_FMT_FLAG_PAL) will have a
palette. Starting with FFmpeg versions which have this flag deprecated, the
extra "pseudo" palette is already ignored, and API users are not required to
allocate a palette for AV_PIX_FMT_FLAG_PSEUDOPAL formats (it was required
before the deprecation, though).
The pixel format is "pseudo-paletted". This means that it contains a fixed palette in the 2nd plane but the palette is fixed/constant for each PIX_FMT. This allows interpreting the data as if it was PAL8, which can in some cases be simpler. Or the data can be interpreted purely based on the pixel format without using the palette. An example of a pseudo-paletted format is AV_PIX_FMT_GRAY8
@deprecated This flag is deprecated, and will be removed. When it is removed, the extra palette allocation in AVFrame.data[1] is removed as well. Only actual paletted formats (as indicated by AV_PIX_FMT_FLAG_PAL) will have a palette. Starting with FFmpeg versions which have this flag deprecated, the extra "pseudo" palette is already ignored, and API users are not required to allocate a palette for AV_PIX_FMT_FLAG_PSEUDOPAL formats (it was required before the deprecation, though).