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JPEG image compression FAQ, part 1/2
Section - [21] What if I need more than 8-bit precision?

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Top Document: JPEG image compression FAQ, part 1/2
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Next Document: [22] How can my program extract image dimensions from a JPEG file?
See reader questions & answers on this topic! - Help others by sharing your knowledge
Baseline JPEG stores images with 8 bits per color sample, in other words
24 bits per pixel for RGB images, 8 bits/pixel for grayscale, 32 bits/pixel
for CMYK, etc.  There is an extension that stores 12 bits/sample for
applications that need higher accuracy.  Medical images, for example, are
often 12-bit grayscale.  The 12-bit extension is not very widely supported,
however.  One package that does support it is the free IJG source code (see
part 2, item 15).

For lossless JPEG, the standard permits any data precision between 2 and 16
bits per sample, but high-precision lossless JPEG is even less widely
supported than high-precision lossy JPEG.  The Stanford PVRG codec (see
part 2, item 15) reportedly supports up to 16 bits/sample for lossless JPEG.

User Contributions:

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David Avs
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Oct 28, 2014 @ 5:17 pm
Progressive JPEG is supported by all modern browsers.

There are libraries and even online tools to automatically convert JPEG files from progressive to baseline and back. For example, Uploadcare uses URL commands to do that:

* JPEG - Progressive: 6fdab0d5-5a07-4b34-8a3a-f61727972745/-/format/jpeg/-/progressive/yes/
* Same JPEG, Baseline: 6fdab0d5-5a07-4b34-8a3a-f61727972745/-/format/jpeg/-/progressive/no/

Here is how it looks in action (when first loaded, you can see how each image starts appearing differently): jsbin.com/nigasotobu/3/

See more docs at Uploadcare website.

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Top Document: JPEG image compression FAQ, part 1/2
Previous Document: [20] Isn't there an M-JPEG standard for motion pictures?
Next Document: [22] How can my program extract image dimensions from a JPEG file?

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Last Update March 27 2014 @ 02:11 PM