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

[Paul B Mahol]

On 4/5/16, Martin Vignali <martin.vignali at gmail.com> wrote:
> 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.

Applied. Thanks.

> Martin Vignali
> Jokyo Images
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