[Ffmpeg-devel] AVPaletteControl removal from libavf (was Re: [MPlayer-dev-eng] [PATCH] (bit hackish) palette support for libav*)

Michael Niedermayer michaelni
Tue Jan 30 16:43:17 CET 2007


On Tue, Jan 30, 2007 at 02:54:40PM +0100, Reimar Doeffinger wrote:
> Hello,
> On Tue, Jan 30, 2007 at 02:30:06PM +0100, Michael Niedermayer wrote:
> > On Tue, Jan 30, 2007 at 01:56:00PM +0100, Reimar Doeffinger wrote:
> > > > also i would pass the palette like a normal video frame into the decoder
> > > > instead of using AVCodecContext
> > > 
> > > Sure, that would be preferable, but how to tell the decoder this is a
> > > palette? Adding a flag parameter to the decode function? That would make
> > > for quite a huge patch a (and a lot of work to make it)...
> > > Advantage: that way could also be used for some other kinds of "extradata".
> > 
> > my hope would be that the decoder could figure out that a packet contains a
> > palette witout any additional info
> Thus probably duplicating complexity from the demuxer in this case. And
> I don't have any idea how this should be possible e.g. in the case of
> raw video e.g. in AVI. 

for raw video the size of the packet could be used ...
anyway we can also pass a flag around but that as you know need
avcodec_decode_video() to be changed (like passing a AVPacket into it)
so code would look like

AVPacket pkt;
pkt.size= mysize;
pkt.data= mydata;
pkt.flags= ispalette ? ...
avcodec_decode_video(..., &pkt, ...);

> If course, that has only one palette that could
> be passed via extradata, but that does not seems like a clean solution
> to me.

well, if the palette is stored in AVIs "extradata" then it will be passed
as extradata, if OTOH its stored in some palette chunk somewhere in the
file then you cannot seek in this file and id say the file is broken

so IMO extradata is where the palette should be in this case

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Democracy is the form of government in which you can choose your dictator
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 189 bytes
Desc: not available
URL: <http://lists.mplayerhq.hu/pipermail/ffmpeg-devel/attachments/20070130/0b5733f3/attachment.pgp>

More information about the ffmpeg-devel mailing list