[gdal-dev] GTiff bit shuffle compression feature request

[Laurențiu Nicola]

On Fri, Dec 8, 2023, at 21:11, Even Rouault wrote:
> 
>> 
>>  - GeoTIFF DEFLATE 280 MB
> Is it with PREDICTOR=3 ?  (If not, then the ZARR datasets should also be compressed with FILTER=DELTA to have a fair comparison)

I would expect a fair comparison to be between PREDICTOR=3 and FILTER=DELTA and not the other way around, but it does seem to level the field significantly:

 - GeoTIFF DEFLATE PREDICTOR=3 255 MB
 - Zarr DELTA BLOSC zlib NONE 290 MB
 - Zarr DELTA BLOSC zlib BIT 266 MB
 - Zarr DELTA BLOSC zlib BYTE 259 MB

>>  - Zarr BLOSC zlib NONE 281 MB
>>  - Zarr BLOSC zlib BIT 253 MB
>>  - Zarr BLOSC zlib BYTE 249 MB
> 

So FILTER=DELTA yields worse compression, while GeoTIFF PREDICTOR=3 does very well. No need for Zarr! I don't remember PREDICTOR=3 doing so well in the past, so.. no idea :-).
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/gdal-dev/attachments/20231208/f005630e/attachment.htm>