The video encoding and decoding software used is based on the public-domain H.263 implementation from Telenor. This C implementation has the versatility of using simple raw binary files for the input and output sequences. All the software development was done on a BSD-Unix platform, with use of the X11R6 library for video display.
Additions and modifications to the encoder and the decoder implementations were considered as the fastest and simplest way to provide the error control functionality. Despite the neatness and flexibility of a modular design which leaves the existing algorithms intact, it was also considered as time-consuming and very complex. Main enhancements include modification of the picture and macroblock type decision, enabling forced intra-mode for them, and temporal prediction error concealment at the decoder.
Apart from the software developed for the simulation itself, some non-trivial tasks were implemented, including programs for the display of still and moving image sequences, file conversion utilities, and various scripts for the calculation, collection, and graphical representation of the results.