[FFmpeg-devel] [PATCH] lavc/qtrle: Use AV_PIX_FMT_PAL8 for 1-bit video

Mats Peterson matsp888 at yahoo.com
Wed Dec 30 11:34:02 CET 2015


On 12/30/2015 08:35 AM, Mats Peterson wrote:
> On 12/30/2015 08:17 AM, Mats Peterson wrote:
>
>>
>> When comparing the output in QuickTime and FFmpeg, I noticed that the
>> background is blue in FFmpeg, while it is white (or transparent, if you
>> will) in QuickTime. Hold your horses on this patch.
>>
>> Mats
>>
>
> I noticed that the "alpha" component (there is NOTHING mentioned about
> this component in the description of the color table in the QuickTime
> File Format Specification, for the record) is set to "1" in the second
> color in the color table. Just wanted to mention that.
>
> Mats
>

One of the major peculiarities in my book is that the two blue colors in 
the video sample description and the white background are THREE colors 
together. Not exactly what I would call 1-bit video. I have absolutely 
no idea what they are doing in QuickTime, since this stuff is totally 
undocumented, but obviously they use three color indices in order to be 
able to provide this white background.

Mats

-- 
Mats Peterson
http://matsp888.no-ip.org/~mats/


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