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

[Martin Vignali]

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

Martin
Jokyo Images
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