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August 1999

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1999.08.12 13:58 "Re: TIFF to JPEG file - how?", by Tom Lane
1999.08.12 15:13 "Re: TIFF to JPEG file - how?", by Kevin D Quitt
1999.08.13 04:55 "Re: TIFF to JPEG file - how?", by Brent Foster

1999.08.13 04:55 "Re: TIFF to JPEG file - how?", by Brent Foster

>If you did such a thing then you wouldn't have produced a lossless copy;
>jpeg_write_raw_data() only avoids colorspace conversion & resampling,
>not DCT.
>
>For single-strip images you really don't have to do anything except
>extract the raw contents of the strip and write it out to a file.
>I think you can persuade libtiff to give you back the physical contents
>of a strip without passing it through any decompressor, but I forget
>how.
>
>Multi-strip images would be considerably harder.  If they're all
>compressed at the same quality setting then in theory you could do it
>(you'd need a souped-up version of jpegtran); but the spec allows for
>varying compression settings between strips/tiles, which cannot be
>losslessly converted to a single 10918-1 JPEG datastream...


How do you do the opposite - put a JPEG into a TIFF without
decompress/compress?
How do you extract the physical properties of the JPEG required for the
TIFF, and what are they?

Thanks,

Brent Foster