Opened 11 years ago

Closed 11 years ago

#2435 closed defect (fixed)

GeoTIFF driver often redecodes pixel interleaved jpeg data

Reported by: warmerdam Owned by: warmerdam
Priority: normal Milestone: 1.5.3
Component: GDAL_Raster Version: 1.5.2
Severity: normal Keywords: gtiff
Cc:

Description

When MapServer? uses GDAL to pull data from a JPEG compressed (or any pixel interleaved) geotiff file it does so in one pass per band. Currently this means that GDAL actually reads and decodes the data three (for RGB) times. For jpeg compressed data (for instance) this is pretty expensive.

It would be desirable if the GeoTIFF driver would push the unrequested bands of data into the block cache for faster subsequent access.

Change History (1)

comment:1 Changed 11 years ago by warmerdam

Resolution: fixed
Status: newclosed

I have implemented pushing into the block cache for the GTiffRasterBand in trunk (r14738) and 1.5 branch (r14739). The GTiffRGBABand would also benefit from this change, but I'm not readily setup to test it, and this class isn't widely used (I think).

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