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<p>Hi,</p>
<p>below is of potential interest for GDAL. We had related
discussions when a Grok GDAL driver was proposed. HTJ2K (ITU-T.814
<a class="moz-txt-link-freetext" href="https://www.itu.int/rec/T-REC-T.814-201906-I/en">https://www.itu.int/rec/T-REC-T.814-201906-I/en</a> or JPEG2000 Part
15) is an extension of regular JPEG2000 were the code block
encoding, which is the slowest part of JPEG2000, has been replaced
by an alternative that has the potential for being 10 times or
more faster (could apparently be 30 times faster for lossless),
with an increased file size of ~ 7%. Current implementation in
OpenJPEG is "only" twice faster.<br>
</p>
<p>I've verified that the current JP2OpenJPEG driver, when linked to
openjpeg master 2.5.0dev, can decode HTJ2K codestreams. This also
works when they are embedded in JP2 boxes (files with .jph
extensions that are similar to .jp2), which is in particular where
georeferencing is encoded (GMLJP2 boxes or GeoJP2 boxes), so
theoretically we should be ready for geospatial imagery using
HTJ2K coding, if such a beast ever emerges...</p>
<p>This is a decode-only implementation. To play with the encoding
side, you'll have to use <a class="moz-txt-link-freetext" href="https://github.com/aous72/OpenJPH">https://github.com/aous72/OpenJPH</a>,
<a class="moz-txt-link-freetext" href="https://github.com/osamu620/OpenHTJ2K">https://github.com/osamu620/OpenHTJ2K</a>,
<a class="moz-txt-link-freetext" href="https://github.com/GrokImageCompression/grok">https://github.com/GrokImageCompression/grok</a> or Kakadu<br>
</p>
<div class="moz-forward-container">Even<br>
<br>
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<th valign="BASELINE" nowrap="nowrap" align="RIGHT">Sujet :
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<td>[OpenJPEG] HTJ2K decoding + github action workflows</td>
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<th valign="BASELINE" nowrap="nowrap" align="RIGHT">Date : </th>
<td>Sat, 25 Sep 2021 13:36:22 +0200</td>
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<th valign="BASELINE" nowrap="nowrap" align="RIGHT">De : </th>
<td>Even Rouault <a class="moz-txt-link-rfc2396E" href="mailto:even.rouault@spatialys.com"><even.rouault@spatialys.com></a></td>
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<th valign="BASELINE" nowrap="nowrap" align="RIGHT">Répondre
à : </th>
<td><a class="moz-txt-link-abbreviated" href="mailto:openjpeg@googlegroups.com">openjpeg@googlegroups.com</a></td>
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<th valign="BASELINE" nowrap="nowrap" align="RIGHT">Pour : </th>
<td>OpenJPEG <a class="moz-txt-link-rfc2396E" href="mailto:openjpeg@googlegroups.com"><openjpeg@googlegroups.com></a></td>
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<br>
Hi,<br>
<br>
some good news to share about latest developments in OpenJPEG
master branch:<br>
<br>
- Aous Naman has made a great contribution by adding a HTJ2K (High
Throughput / Part-15) decoder. See
<a class="moz-txt-link-freetext" href="https://github.com/uclouvain/openjpeg/pull/1381">https://github.com/uclouvain/openjpeg/pull/1381</a> for details and
limitations. My quick experiment (see
<a class="moz-txt-link-freetext" href="https://github.com/uclouvain/openjpeg/pull/1374#issuecomment-926894225">https://github.com/uclouvain/openjpeg/pull/1374#issuecomment-926894225</a>)
shows a ~ x2 speed improvement in mono-threaded decompression
compared to regular Part-1 code block style.<br>
<br>
- I've migrated most of the continuous integration target to
github action workflows. The driver for this is that Travis-CI is
no longer friendly to open source projects due to a limited small
quota that was exhausted for our project. github action workflows
are naturally inherited in forks, so you can potentially work on a
branch for some time, push in your clone, check CI results and
just issue a pull request when you're done.<br>
<br>
Even<br>
<br>
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