An interactive program guide (IPG) may include a program grid section and
a multimedia section. The program grid section typically contains program
information organized in a grid with a time axis and a channel axis. The
multimedia section may include video for advertisement, previews, and
other purposes. Such an IPG may be rendered and encoded at a server and
distributed to client terminals in the form of compressed bit streams.For
certain IPGs, the program grid section may comprise alternating stripes
of background with different shades (lighter/darker) or different colors.
Typically, the alternating background stripes may be used to visually
separate text information into timeslots or channels.Blank areas of the
background may be "skip" encoded to "save" a portion of the bit rate.
Meanwhile, the quantizer stepsize for encoding that section may be
lowered so as to utilize the saved bits to improve the viewing quality of
the program grid section. Additionally or alternatively, the quantization
matrix for encoding the program grid section may be optimized for
encoding text (rather than being, for example, a standard quantization
matrix).Encoding may be performed on the program grid section such that
encoded macroblocks do not cross a border between two stripes. In other
words, each encoded macroblock in the program grid section may be within
a single stripe. Additionally or alternatively, low-pass frequency
filtering may be applied on the background stripes. Such low-pass
filtering reduces visual defects due to ringing from edges between
stripes.