2011.02.13 08:39 "Re: [Tiff] JPEG issues with tiffcp", by

Bob,

I don't think that there is any alternative other than to decompress and recompress the JPEG data since OJPEG and JPEG are different.

The container is different, but the JPEG compressed data in them is the same. In fact, the old-style JPEG decoder in LibTiff has been build with this need in mind. It converts the old-style JPEG data to a full and legit JPEG stream, complete with all required markers and table headers and all, and feeds this to LibJpeg, so as to be able to extend it one day to deliver the same full and legit JPEG stream to other causes, like simply saving to file for lossless TIFF-OJPEG->JPEG conversion, or saving as a single-strip in a TIFF IFD for lossless TIFF-OJPEG->TIFF-JPEG conversion.

Such a lossless conversion should be regarded highly recommended over recompression, as JPEG loss cummulates badly.

Best regards,

Joris