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

Michael Niedermayer michaelni
Tue Jan 30 14:30:06 CET 2007


Hi

On Tue, Jan 30, 2007 at 01:56:00PM +0100, Reimar Doeffinger wrote:
> Hello,
> On Tue, Jan 30, 2007 at 12:13:11AM +0100, Michael Niedermayer wrote:
> > On Mon, Jan 29, 2007 at 11:03:26PM +0100, Reimar D?ffinger wrote:
> > > @@ -498,6 +497,13 @@
> > >      /* make a note of where the stream is sitting */
> > >      s->next_chunk_offset = url_ftell(pb);
> > >  
> > > +    if (palette_changed) {
> > > +        if (av_new_packet(pkt, AVPALETTE_SIZE))
> > > +            chunk_type = CHUNK_NOMEM;
> > > +        memcpy(pkt->data, s->palette, AVPALETTE_SIZE);
> > 
> > are you aware that you put endian specific data into the AVPacket? this is
> > not good at all
> > i would rather pass the palette as it is stored to the decoder (unless of
> > course the specific codec can be stored in several containers and expects
> > some specific format)
> 
> The way it is stored is a partial and in additon 6 bit per component
> palette. 

yes and that should be put in the AVPacket, currently the demuxer decodes
the palette but that IMHO belongs to the decoder


[...]
> > 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

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

I have never wished to cater to the crowd; for what I know they do not
approve, and what they approve I do not know. -- Epicurus
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