Talk:Image file formats
List of interesting formats
These formats are quite attractive but have some problems - thus are not yet included in standard supported set.
DJVU
Format designed for text scans. Most printed text include a lot of similar shapes (letters). And small differences are not important (usually they are artefacts of scanning). DVJU uses this fact to reduce size of files - the cost is CPU and RAM usage. There are free reader/writer/converter.
- This is not really an image format. It is more of an ebook compression format for scanned books. Therefore I have discussed this on a page about ebook formats. It is one of the formats supported by Evince and it allows existing paper books to be quickly and efficiently distributed on the OLPC without any worries about Unicode and font support.
JBIG
Format designed by JPEG Group for bi-level (black and white) images. Can be used to effectively compress scans. There are free reader and writer.
JPEG 2000
This is "JPEG for 21 century". It uses wavelets and usually offer better compression then JPEG or better quality (both formats are lossy so you can choose better quality or better compression). It's much nicer is regard to sharp edges (i.e. text and diagrams) but requires more processor power so it's not clear if it's good trade-off for OLPC. There are free reader/writer/converter.
MNG
While PNG is GIF-replacement without animation support MNG goes further and adds animations and JPEG-compression to it. Perhaps better to stick with combination of JPEG/PNG (or may be JPEG 2000/PNG) and SVG (SVG can refer to external JPEG/PNG files). There are free reader/writer/converter.
List of objectionable formats
Here is list of formats readable by different free software readers. Most of them should not be used by OLPC programs.
BMP
This is old proprietary format developed more then 10 years ago by Microsoft. Does not offer alpha-channels, even microsoft is switching from BMP to PNG.
SWF
Format initially developed for Macromedia Flash. Has a lot of nice features but can only be played by Macromedia Flash Player. There are free player but it's not 100% compatible (and probably never will be 100% compatible).
- Most of what Flash can do is supported by SVG. There are converters available for existing content such as http://www.eprg.org/~sgp/swf2svg.html and http://www.titan.napier.ac.uk/~05011301/ however, Flash content is often full of a lot of animated fluffy eye-candy that does not contribute to the goal of educating children interactively.
TIFF
Extensible image format. CMYK, LZW, JPEG, RLE, layers and multipage... A lot of features are important for desktop publishing but probably useless for OLPC.
WMF
This is old proprietary format developed more then 10 years ago by Microsoft. You can use libwmf (free software) or SVG Factory (freeware, no sources) to convert images to SVG. Some images will be mangled in conversion - what do you expect from proprietary format with poor documentation ?
Discussion
Can someone with actual OLPC hardware play with JasPer to see if it's speed is acceptable for OLPC needs ? Can someone compare jbig2enc and DjVuLibre for scans compression ?