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Re: jpegtran lossless rotation?

On Mon, 2005-01-24 at 19:18 +0900, Victor Munoz wrote:
> Hello. I'm a bit confused. jpegtran is supposed to provide lossless 
> transformation on jpg files. Understanding nothing about the internals of 
> graphic formats, I'd expect that original and transformed files had the same
> number of bytes. However, if I apply it to some file from my digital camera,
> the command:
> jpegtran -rotate 90 -copy all pict0069.jpg > l.jpg
> yields:
> -rw-r--r--    1 vmunoz   vmunoz     436513 Jan 24 19:06 l.jpg
> -r--r--r--    1 vmunoz   vmunoz     440635 Jan 24 18:39 pict0069.jpg
> which is almost the same. Does anybody know where do the 'lost' bytes belong
> to? Exif data? I checked 'exif l.jpg', and 'exif pict0069.jpg', and 
> the output is exactly the same. 
> I know I'm being obsessive, but does anyone know?

That 1% difference in file size probably has to do with how it
encodes different patterns of colors and intensities.

Ron Johnson, Jr.
Jefferson, LA USA
PGP Key ID 8834C06B I prefer encrypted mail.

296,443 sq mi (767,787 sq km) are needed for 6 billion people to
live at the same population density as Manhattan, New York.
That is ~ Arizona or Nevada.
Alternatively, that ~ double the size of Japan or Zimbabwe

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