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+# Supported File Formats #
+
+crnlib supports two compressed texture file formats. The first
+format (clustered [.DDS](http://en.wikipedia.org/wiki/DirectDraw_Surface)) is simple to integrate into an existing project
+(no code changes are typically required), but it doesn't offer the
+highest quality/compression ratio that crnlib is capable of. Integrating
+the second, higher quality custom format (.CRN) requires a few
+typically straightforward engine modifications to integrate the
+.CRN->DXTn transcoder header file library into your tools/engine.
+
+## .DDS ##
+crnlib can compress textures to standard DX9-style [.DDS](http://en.wikipedia.org/wiki/DirectDraw_Surface) files using
+clustered DXTn compression, which is a subset of the approach used to
+create .CRN files. (For completeness, crnlib also supports vanilla, block by block DXTn compression too, but that's not very interesting.)
+Clustered DXTn compressed .DDS files are much more compressible than
+files created by other libraries/tools. Apart from increased
+compressibility, the .DDS files generated by this process are completely
+standard so they should be fairly easy to add to a project with little
+to no code changes.
+
+To actually benefit from clustered DXTn .DDS files, your engine needs to
+further losslessly compress the .DDS data generated by crnlib using a
+lossless codec such as zlib, lzo, LZMA, LZHAM, etc. Most likely, your
+engine does this already. (If not, you definitely should because DXTn
+compressed textures generally contain a large amount of highly redundant
+data.)
+
+Clustered .DDS files are intended to be the simplest/fastest way to
+integrate crnlib's tech into a project.
+
+## .CRN ##
+The second, better, option is to compress your textures to .CRN files
+using crnlib. To read the resulting .CRN data, you must add the .CRN
+transcoder library (located in the included single file, stand-alone
+header file library inc/crn\_decomp.h) into your application. .CRN files
+provide noticeably higher quality at the same effective bitrate compared
+to clustered DXTn compressed .DDS files. Also, .CRN files don't require
+further lossless compression because they're already highly compressed.
+
+.CRN files are a bit more difficult/risky to integrate into a project, but
+the resulting compression ratio and quality is superior vs. clustered .DDS files.