[FFmpeg-devel] [PATCH 1/2] lavf/avienc: Simplify palette handling

Mats Peterson matsp888 at yahoo.com
Sat Feb 27 19:35:19 CET 2016


On 02/27/2016 07:18 PM, Reimar Döffinger wrote:
> On Sat, Feb 27, 2016 at 06:05:20PM +0100, Mats Peterson wrote:
>> On 02/27/2016 05:45 PM, Reimar Döffinger wrote:
>>>> Not that it couldn't be done with side data packets, though.
>>>
>>> If it doesn't support side data then the muxers are plain broken.
>>
>> The muxers should support side data, I agree on that. The thing is the
>> packets come in to the AVI, QuickTime and nut muxers with the palette data
>> appended to the video data in the packets.
>
> You never answered that actually...
> How do the come in that way?!?
> That's not what e.g. the matroska demuxer produces, so stream
> copying with some generic remuxing example I am really sure that is
> NOT how the packets come in.
>

That's apparently how things work in FFmpeg at the moment. There is 
currently no palette side data used by the *FFmpeg* muxers. The palette 
is appended to the packets. Ask Michael for further details, he can 
probably explain this better than me.

>
> I can't see HOW they even COULD work right now?!
> Otherwise I wouldn't really care, but as far as I can
> tell I don't see how it could work at all but for
> some lucky exceptions.
> What cases have we actually tested to work?
> _______________________________________________

In spite of the mixed use of side data and palette in packets, things 
work just fine. FFplay currently plays all palettized files correctly, 
and FFmpeg produces palettized files correctly, after my recent patches.

Mats



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