[FFmpeg-devel] [PATCH v28] lavf/movenc: Add palette to video sample description

Mats Peterson matsp888 at yahoo.com
Fri Feb 26 06:40:27 CET 2016


On 02/26/2016 06:24 AM, Mats Peterson wrote:
> On 02/26/2016 05:26 AM, Mats Peterson wrote:
>> On 02/26/2016 05:08 AM, Mats Peterson wrote:
>>> Should hopefully fix the big-endian issue.
>>>
>>
>> Not that I understand why. I thought the palette was already in
>> "big-endian" order, with the A, R, G, B bytes in that order, and that
>> the previous patch would rather fail instead, so to say. But alright.
>>
>> Mats
>>
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>
>
> After applying this patch, would you like to try "ffmpeg -i 8bpp_129.mov
> -vcodec rawvideo out.mov" with the file below on that mips machine, just
> to see that nothing is wrong with the palette storage on the demuxer side?
>
> https://drive.google.com/open?id=0B3_pEBoLs0fabUdRcTVxRl9yVWM
>
> Mats
>

Look at this snippet from libavformat/qtpalette.c that stores a palette 
entry (palette[] is uint32_t):

palette[i] = (a << 24 ) | (r << 16) | (g << 8) | (b);

The way it is stored in memory is obviously dependent on the endianness 
of the machine. For little-endian machines, it will be BGRA, and for 
big-endian ones ARGB.

Mats

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


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