To provide methods and systems for start code emulation prevention at a granularity higher than the bit level.

By operating at a level other than the bit level, processing capability requirements can be reduced on both encoder and decoder sides. A start code emulation prevention method looks for data patterns relative to fixed-size data portions larger than single bits. When a particular pattern is found, start code emulation prevention data are inserted to prevent start code emulation. The inserted data are larger than a single bit and comprise a byte. When a decoder decodes data which have had start code emulation prevention data inserted, it can easily identify legitimate start codes and then can remove the start code emulation prevention data to provide the original data which are protected.