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F060801 - What are the differences among MG2, MG3 and JP2 formats?
MrSID Generation 2 (MG2)
MrSID Generation 2 is the original MrSID format and is still supported in more applications than MG3 or JP2, although the difference is gradually diminishing. MG2 is limited to 2GB in file size and is essentially for compression. It does not support the more advanced capabilities available in MrSID Generation 3 and JPEG 2000.
MrSID Generation 3 (MG3)
MrSID Generation 3 is the latest generation of MrSID. MG3 supports unlimited file sizes, lossless encoding with optimization, manipulation functions such as area of interest encoding. MG3's optimization capabilities mean that you do not have to run another encoding process to increase the compression ratio, crop your image, or apply an area of interest. MG3 is supported in more applications than JP2, though this is changing as JP2 gains greater acceptance.
JPEG 2000 (JP2)
JPEG 2000 is an ISO standard that allows for more user-specified encode parameters ("knobs and dials") than MG3, a customizability that gives it the potential to perform better than MG3 at decode time, provided that the parameters chosen correctly anticipate the particular workflow that the imagery is used for. JP2 typically compresses faster than MG3, and unlike MrSID formats, JP2 supports multispectral imagery.
While MrSID was designed especially for geospatial images, JPEG 2000 does not specify a standard method for handling geospatial or any other metadata, which has hampered its adoption in the geospatial industry. However, JPEG 2000 supports XML, and recent developments that facilitate encoding XML-based Geography Markup Language (GML) metadata in JP2 files are paving the way for greater interoperability between JP2 and geospatial applications.
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