On Sat, Apr 02, 2011 at 09:12:05PM +1100, Peter Ross wrote: > On Sat, Apr 02, 2011 at 10:54:42AM +0100, Måns Rullgård wrote: > > Kostya <[email protected]> writes: > > > > > Situation so far: > > > 0) we have codecs that operate in paletted colourspace and palette > > > changes may > > > be signalled outside codec data (like AVI which has special "palette > > > change" > > > chunks) > > > 1) we had AVPaletteControl which was broken if application didn't use > > > "demux-decode-demux-decode" approach > > > 2) certain somebody decided that in AVI case it should be handled by > > > appending > > > 1024 bytes with changed palette to demuxed packet and codecs should check > > > if > > > they have some undecoded data left (commit ID b7c40744). Naturally no > > > codec > > > was changed to do that so some codecs relying on it produce pictures with > > > broken colours (let alone remuxing): > > > http://samples.multimedia.cx/avi/palette_change/toon.avi > > > http://samples.multimedia.cx/V-codecs/KMVC/baseball1.avi > > > http://samples.multimedia.cx/V-codecs/QPEG/VWbig6.avi > > > (raw http://samples.multimedia.cx/game-formats/yop/CIMOVI01.avi works by > > > some > > > coincidence). > > > > > > I think this can be resolved by passing new palette in AVPacket in some > > > way: > > > 0) do nothing and pretent that problem doesn't exist > > > 1a) just add AV_PKG_FLAG_PAL and make codec treat last 1024 bytes of data > > > as > > > palette (should be done for muxers too). Alternatively packet size may be > > > hacked so palette will be after declared packet end (but that's too hacky > > > to > > > my taste). > > > 1å) add AV_PKT_FLAG_PAL and pass only palette change in packet (it may > > > break > > > timestamp handling, I fear) > > > 2) introduce some specific fields in AVPacket for passing such information > > > (too hacky IMO) > > Must say, I am glad somebody is thinking about this problem.
Guess who added that chunk support in the first place and some codecs that use it? > > Put the new palette in AVPacket.data[1]. > > +1 for keeping the coded frame and the palette information together.! Indeed, the question is how exactly. _______________________________________________ libav-devel mailing list [email protected] https://lists.libav.org/mailman/listinfo/libav-devel
