A Technical Comparison between PDF and DJVU

Item	PDF	DJVU
Description of Layout	Driven by (a subset of) PostScript
Structure (brief)	object based, offset of indirect objects	described with device independent Cartesian coordinate system
Characters	Font-based	Rendering characters as images
Imaging Features	described with device independent Cartesian coordinate system, named graphical elements
Vector Graphics	Constructed with Paths, as defined in PostScript, with various patterns	Not mentioned Likely not supported
Raster Images (coding techniques)	<!--[if !supportLists]-->1. <!--[endif]-->ASCII Coding (somewhat deprecated) <!--[if !supportLists]-->2. <!--[endif]-->Run-length coding <!--[if !supportLists]-->3. <!--[endif]-->Dictionary coding, LZW, FLATE, … <!--[if !supportLists]-->4. <!--[endif]-->Built-in compressor with prevailing image compression standards: JPEG; JBIG(PDF1.4); JPEG2000(PDF 1.5)	<!--[if !supportLists]-->1. <!--[endif]-->3-level text-background separation, specified IW44 wavelet compression for background and foreground, JB2 for bi-level mask image, which takes advantage of the similarity between shapes on the page, e.g. nearly-identicalness of literal symbols of same character and font. <!--[if !supportLists]-->2. <!--[endif]-->Arithmetic coding <!--[if !supportLists]-->3. <!--[endif]-->Progressive loading
OCR	Supported	Supported
Advantage	Vector graphics	Scanned (raster) images / documents high quality and high compression rate
Conclusion	One of the most popular and practicable way of presenting book in computer	Excellent compression method for text-based image sequences
Supported elements	[All those supported by DJVU] Sound Interactive forms Javascript programs	Table Hyper link Meta-data
DRM	Supported	Not specified