Contents

1 Intro

• RLE for bin-ary alphabets.
• In this case, it is not necessary to indicate the next symbol (only the length) because if a run ends, the other (possible) symbol start with the next run.

2 Encoder

1. Let $s\leftarrow$ 0.
2. While there are bits to encode:
   1. Read the next $n$ consecutive bits equal to $s$.
   2. Write $n$.
   3. $s\leftarrow \left(s+1\right)\text{modulus}2$.

3 Decoder

1. Let $s\leftarrow$ 0.
2. While there are items $n$ to decode:
   1. Write $n$ bits equal to $s$.
   2. $s\leftarrow \left(s+1\right)\text{modulus}2$.

Example

The runs:

are encoded as::