Compute the runs of a string
Pyth, 38 bytes

{smm,hk+ekdfgaFTdcx1xM.ttB+0qVQ&gt;QdZ2Sl

  m                                 SlQ   map for d in [1, …, len(input)]:
                            qVQ&gt;Qd          pairwise equality of input[:-d] and input[d:]
                        tB+0                duplicate this list, prepending 0 to one copy
                      .t          Z         transpose, padding with 0
                    xM                      pairwise xor
                  x1                        find all occurrences of 1
                 c                 2        chop into groups of 2
           f                                filter for groups T such that:
             aFT                              the absolute difference between its elements
            g   d                             is greater than or equal to d
   m                                        map for groups k:
     hk                                       first element
    ,  +ekd                                   pair with the last element plus d
 s                                        concatenate
}                                         deduplicate


Test suite