[FFmpeg-devel] [PATCH] lavf/qtpalette: Ignore greyscale bit in 1-bit video

Mats Peterson matsp888 at yahoo.com
Thu Dec 31 18:15:12 CET 2015

On 12/31/2015 05:04 PM, Mats Peterson wrote:
> Alright, Michael, do whatever you want, but it's awkward to have this
> patch lying around for no reason, when it's such a small change.
> Mats

Let me repeat a snippet from the QuickTime File Format Specification:

"Depth: A 16-bit integer that indicates the pixel depth of the 
compressed image. Values of 1, 2, 4, 8 ,16, 24, and 32 indicate the 
depth *of color images*. The value 32 should be used only if the image 
contains an alpha channel. Values of 34, 36, and 40 indicate 2-, 4-, and 
8-bit grayscale, respectively, for grayscale images."

Notice that 1-bit depth is in the category "color images". There is 
nothing to hesitate about here. Also, once again, no mention of value 33 
(1-bit video with the greyscale bit set) in the grayscale sentence. 
Hence, the greyscale bit should be ignored in 1-bit video.


Mats Peterson

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