I have a very old GDAL based tool I wrote that creates JPEG thumbnails for GeoTiff's. Since the GeoTiff's can be any size and I used a perl script to compute the aspect ratio so I can center a reduced size image in a square thumbnail.
I'm looking for any suggestions as to how I can look into the problem which is described below. 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. Since our production system has a very old version I upgraded GDAL to 1.8.1 and have observed the same problem. Turns out it appears to be VRT related and only happens with single band (black/white imagery). If I use gdal_tranlsate to just translate the image to JPEG I get a properly placed EOI (d9ff): [ealpert@sbsenoklgmt07] PACK $ gdal_translate -of JPEG 1020010016BB5500.tif 1020010016BB5500_new.jpg Input file size is 1356, 7444 0...10...20...30...40...50...60...70...80...90...100 - done. ealpert@sbsenoklgmt07] PACK $ od -t x2 1020010016BB5500_new.jpg | tail 10610460 288a 8aa2 a228 288a 8aa2 a228 288a 8aa2 10610500 a228 288a 8aa2 a228 288a 8aa2 a228 288a 10610520 8aa2 a228 288a 8aa2 a228 288a 8aa2 a228 10610540 288a 8aa2 a228 288a 8aa2 a228 288a 8aa2 10610560 a228 288a 8aa2 a228 288a 8aa2 a228 288a 10610600 8aa2 a228 288a 8aa2 a228 288a 8aa2 a228 10610620 288a 8aa2 a228 288a 8aa2 a228 288a 8aa2 10610640 a228 288a 8aa2 a228 288a 8aa2 a228 2b8a 10610660 d9ff If I create a VRT to center the image then use gdal_translate to convert I get the following error message and the JPEG has garbage at the end but can still be viewed without any problems in all applications: ERROR: bit length overflow code 3 bits 6->7 VRT: <VRTDataset rasterXSize="1024" rasterYSize="1024"> <NoDataValue>255</NoDataValue> <VRTRasterBand dataType="Byte" band="1"> <ColorInterp>Gray</ColorInterp> <NoDataValue>255</NoDataValue> <ComplexSource> <NODATA>0</NODATA> <SourceFilename relativeToVRT="1">./1020010016BB5500.tif</SourceFilename> <SourceBand>1</SourceBand> <SrcRect xOff="0" yOff="0" xSize="1356" ySize="7444"/> <DstRect xOff="419" yOff="0" xSize="186" ySize="1024"/> </ComplexSource> </VRTRasterBand> </VRTDataset> [ealpert@sbsenoklgmt07] PACK $ gdal_translate -of JPEG test.vrt test.jpg Input file size is 1024, 1024 0...10...20...30...40...50...60...70...80...90...100 - done. bit length overflow code 3 bits 6->7 [ealpert@sbsenoklgmt07] PACK $ od -t x2 test.jpg | tail 0231300 90bb 1db7 3ee6 d116 d6fe f50c a157 126c 0231320 ff32 6f98 fb44 9a7f 1f57 7db8 9f90 99ff 0231340 047e 65ce b9f3 fe78 cdcf 4137 e390 105f 0231360 bfaf f372 1fed bd27 a8fe 002b 6c9d bbff 0231400 163d 637d bfe7 b716 ebfe ff7a f6a6 97c3 0231420 fad2 fb37 16fa f160 b7fe ebab 2e5f f985 0231440 ef6f f9b1 b347 293b 1037 9fbe 416f 697b 0231460 b1fd 84ea 8b9b 690b 13ff 5707 07fc df17 0231500 ef84 087f 870e e51b 0127 0000 Note there is no EOI marker. 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.
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