Why JPEG is not JPEG — Testing a 25 years old Standard

While ISO WG1 recently celebrated the 25th anniversary of its most successful standard, it seems to be more than surprising that up to now, no reference implementation of this standard exists. During an ongoing activity aiming at filling this gap, several observations have been made in how far the “living standard” deviates from the ISO documents. In particular, applying the official reference testing procedure of JPEG, available as ITU Recommendation T.83 or ISO/IEC 10918-2, turned out to be more a challenge than expected. This document sheds some light on the JPEG ISO standard, and our findings during reference testing a legacy, 25 year old standard.