Hi Andreas,
On 6/9/20 1:47 PM, Andreas Neumann wrote:
Hi Marco,
I agree. WebP would be interesting. It could potentially replace both
png and jpeg - if encoding and decoding is fast and if filesize can
compete. The good thing of WebP compared with JPEG is that it supports
transparency.
Exactly !
According to your brief study, it seems to score well regarding file
size, but not so well performance wise - correct?
Encoding and decoding performance seems to be a bit worse. But this
could be compensated by the smaller size and faster transfer.
The performance that you measure - is this about time to create the
files - right?
The times are rendering times (decoding).
What about opening and rendering on the client? That's the other side
of the medal.
Does qt support WebP?
Yes
Regarding your blog post: can you perhaps better explain what PNG_JPEG
means? A PNG as a container with JPEG compression inside? Or what is it?
Have a look at the GDAL driver page
https://gdal.org/drivers/raster/gpkg.html
[ ... ] PNG tiles will be used to store tiles that are not completely
opaque [ ... ]
Regarding tif: could you share your creation parameters? In my
experience tiff performs much better than what you experience (both in
file size and speed) if you use proper compression and creation
parameters. E.g. you can use JPEG compression inside tiff and then you
should have more or less the same file size as with jpeg. tiff is just
the container, but there are thousand of combinations of creation
options that have a very, very significant impact on perfomance and
file size.
Can you ask this question directly as a comment on the blog post? Lucie
who is not in the office created the post and has all the parameters.
Bests
Matthias
Thanks,
Andreas
On 2020-06-09 13:26, Matthias Kuhn wrote:
Hi all,
At OPENGIS.ch we have recently looked into different raster formats.
The results can be read here:
https://www.opengis.ch/2020/06/09/offline-wms-benchmarking-raster-formats-for-qfield/
Not that surprising, but one of the interesting findings was that
webp is very efficient. Low filesize, reasonable rendering
performance, support for transparency. In short, it has all the
potential for being used as default transport format for WM(T)S.
Looking at our server implementation, this format is not supported.
Did someone ever think about or even look into that?
Regards
--
Matthias Kuhn
[email protected] <mailto:[email protected]>
+41 (0)76 435 67 63 <tel:+41764356763>
OPENGIS.ch Logo <http://www.opengis.ch>
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