[FFmpeg-devel] libavcodec/exr : enable support for mipmap/ripmap tile.

[Martin Vignali]

2016-04-05 22:31 GMT+02:00 Paul B Mahol <onemda at gmail.com>:

> On 4/5/16, Martin Vignali <martin.vignali at gmail.com> wrote:
> > Hello,
> >
> > Mipmap and ripmap is two way to store several resolution of the picture
> > inside an exr file
> > The difference between these two mode, is the number of subres level (lot
> > more subres in ripmap, than mipmap).
> > These files are mainly design to store maps for 3D render.
> >
> > After some tests on official samples, it seems that mipmap and ripmap exr
> > file, store the full res tiles before subres tiles.
> > So the actual way of decoding tile, works fine with mipmap and ripmap
> (only
> > calc the full res tile count), run decode_block for theses tile.
> >
> > So i think the patch in attach works fine for mipmap and ripmap.
> >
> > I also ignore now, the tile round mode, because this value, is only, for
> > detecting tile count in subres level
> >
> > This patch decode fine all Multiresolution tile files of the official
> > libray :
> >
> http://download.savannah.nongnu.org/releases/openexr/openexr-images-1.7.0.tar.gz
> >
> > except : WavyLinesSphere.exr
> > But this file, is in fact not a Multiresolution file (exrheader
> information
> > show that it's a scanline PIZ).
> > And i suppose the decoding error, is related, to ticket
> > https://trac.ffmpeg.org/ticket/3932
> >
> >
> > Comments welcome
>
> Shouldn't there be option use lower resolution tiles?
>
> It can be a future feature.

I prefer for now,  focus on adding support for kinds of exr who can't be
decode at all.

Martin Vignali
Jokyo Images