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78 wiersze
3.6 KiB
HTML
<!-- received="Mon Mar 15 12:56:37 1999 PST" -->
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<!-- sent="Mon, 15 Mar 1999 17:50:56 +0100" -->
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<!-- name="Oliver Rauch" -->
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<!-- email="oliver.rauch@Wolfsburg.DE" -->
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<!-- subject="Re: 16 bit per sample support" -->
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<title>sane-devel: Re: 16 bit per sample support</title>
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<h1>Re: 16 bit per sample support</h1>
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<b>Oliver Rauch</b> (<a href="mailto:oliver.rauch@Wolfsburg.DE"><i>oliver.rauch@Wolfsburg.DE</i></a>)<br>
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<i>Mon, 15 Mar 1999 17:50:56 +0100</i>
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<p>
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<ul>
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<li> <b>Messages sorted by:</b> <a href="date.html#151">[ date ]</a><a href="index.html#151">[ thread ]</a><a href="subject.html#151">[ subject ]</a><a href="author.html#151">[ author ]</a>
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<li> <b>Next message:</b> <a href="0152.html">Oliver Rauch: "xsane-0.16 with experimental 16 bpp support available"</a>
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<li> <b>Previous message:</b> <a href="0150.html">Peter Kirchgessner: "Re: HP Photosmart R032"</a>
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<li> <b>Maybe in reply to:</b> <a href="0126.html">Oliver Rauch: "16 bit per sample support"</a>
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</ul>
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Andreas Dilger wrote:<br>
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<p>
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<i>> > In the sane api it is not define how bit depths between 8 and 16 bits are</i><br>
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<i>> > handled. So if the scanner gives back 12 bpp is this bit 0-11 or bit 5-16</i><br>
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<i>> > or does this mean the colors are mixed togeht in some bytes:</i><br>
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<i>> > (8 bits red) (4 bits red, 4 bits green) (8 bits green) (8 bits blue) (4 bits</i><br>
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<i>> > blue, whats with the rest?)</i><br>
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<i>></i><br>
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<i>> I would suggest that for backends that support > 8 bit/sample output, that sane</i><br>
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<i>> return the data in the high-order bits, and then if you don't need the extra</i><br>
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<i>> bits (eg for display on the screen), you can simply truncate the low-order</i><br>
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<i>> bits and treat it like 8 bits/sample. This is how PNG stores the data, whether</i><br>
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<i>> 5 bps or 12 bps -> it only really "stores" either 8 or 16 bits/sample, and</i><br>
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<i>> converts all other bit depths to fit.</i><br>
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<i>></i><br>
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<p>
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It does not matter how we define it, there are advantages and disadvantages<br>
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for both possibilities. The point is that is has to be defined!<br>
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<p>
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We also can add a maxvalue item to the parameters block and let<br>
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<p>
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<i>> As a side note, it should be defined whether you have high-byte first (network</i><br>
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<i>> byte order), or low byte first (intel order). I would vote for network byte</i><br>
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<i>> order, since this is the same as PNG, and then you can just dump the data</i><br>
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<i>> into a PNG file.</i><br>
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<i>></i><br>
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<p>
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That already is defined in the sane api and hsould not be changed any more!<br>
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<p>
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Bye<br>
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Oliver<br>
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<p>
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<pre>
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--
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EMAIL: <a href="mailto:Oliver.Rauch@Wolfsburg.DE">Oliver.Rauch@Wolfsburg.DE</a>
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WWW: <a href="http://www.wolfsburg.de/~rauch">http://www.wolfsburg.de/~rauch</a>
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<p>
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<p>
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<p>
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<p>
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<pre>
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--
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Source code, list archive, and docs: <a href="http://www.mostang.com/sane/">http://www.mostang.com/sane/</a>
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</pre>
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<!-- body="end" -->
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<p>
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<ul>
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<!-- next="start" -->
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<li> <b>Next message:</b> <a href="0152.html">Oliver Rauch: "xsane-0.16 with experimental 16 bpp support available"</a>
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<li> <b>Previous message:</b> <a href="0150.html">Peter Kirchgessner: "Re: HP Photosmart R032"</a>
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<li> <b>Maybe in reply to:</b> <a href="0126.html">Oliver Rauch: "16 bit per sample support"</a>
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<!-- nextthread="start" -->
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<!-- reply="end" -->
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</ul>
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