Ethan, It only happens if there appears to be a valid mask on the source image that gets copied by gdal_translate in a CreateCopy() call to the jpeg driver. There are various reasons a source might or might not have a mask.
Best regards, Frank On Fri, Apr 13, 2012 at 2:31 PM, Ethan Alpert <ealp...@digitalglobe.com> wrote: > Ok why does this not happen with multi band jpgs? > > > > From: Even Rouault [mailto:even.roua...@mines-paris.org] > Sent: Friday, April 13, 2012 1:13 PM > To: gdal-dev@lists.osgeo.org > Cc: Ethan Alpert > Subject: Re: [gdal-dev] Problem with garbage bytes of data after EOI marker > in single band JPEG > > > > Le vendredi 13 avril 2012 19:53:41, Ethan Alpert a écrit : > >> > >> This has been running for years. Recently a customer who receives these > >> started scanning the JPG's for security threats. Turns out that the > >> JPG's I've been writing have garbage data after the JPEG EOI marker. > >> > > This is not garbage, but mask data appended after the JPEG data stream, as > documented in the JPEG driver doc : > > """The driver also supports the "zlib compressed mask appended to the file" > > approach used by a few data providers to add a bitmask to identify pixels > that > > are not valid data.""" > > The mask is due to the advertized nodata value in the VRT. You can likely > remove it by adding <HideNoDataValue>1</HideNoDataValue> in the VRT file > under the VRTRasterBand element. > > This electronic communication and any attachments may contain confidential > and proprietary > information of DigitalGlobe, Inc. If you are not the intended recipient, or > an agent or employee > responsible for delivering this communication to the intended recipient, or > if you have received > this communication in error, please do not print, copy, retransmit, > disseminate or > otherwise use the information. Please indicate to the sender that you have > received this > communication in error, and delete the copy you received. DigitalGlobe > reserves the > right to monitor any electronic communication sent or received by its > employees, agents > or representatives. > > > _______________________________________________ > gdal-dev mailing list > gdal-dev@lists.osgeo.org > http://lists.osgeo.org/mailman/listinfo/gdal-dev -- ---------------------------------------+-------------------------------------- I set the clouds in motion - turn up | Frank Warmerdam, warmer...@pobox.com light and sound - activate the windows | http://pobox.com/~warmerdam and watch the world go round - Rush | Geospatial Software Developer _______________________________________________ gdal-dev mailing list gdal-dev@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/gdal-dev