Re: [Openexr-devel] Fast loading of OpenEXR files with RGBZ data

[Florian Kainz]

Gernot,

Most likely you will get the fastest playback rates with
uncompressed images.  Compression and decompression add
significantly to the I/O times for OpenEXR images.  You
may want to try RLE compression; the run-time overhead
is fairly small.  However, photographic images do not
compress very much with RLE.

Regarding API calls, the IlmImf library does not contain
any hidden calls for "faster than usual" pixel data
retrieval.  I recommend reading the files via the regular
InputFile class (class RgbaInputFile won't work since you
want to get access to the Z channel).  For maximum speed,
you should read the entire file with a single readPixels()
call.

Using uncompressed files, you should be able to read
image sequences with normal video resolution in real-time.
For high-definition video resolution you will need a very
fast computer.

A number of people have expressed interest in better support
real-time playback of high-resolution image sequences, and
we are currently investigating how this should be done
(faster/parallel decompression, optimized data paths through
the library, overlapped reading/decoding of multiple frames).

Florian