Heh, I didn't expect any problems when implementing EOR, good thing I did, I found a bug in the spec: for(; j<n && j<syncpoints; j++){ if (!has_keyframe[j][i]) continue A v if(!A){ A v B v eor_pts[j][i] = last_pts + A + B }else B=0 keyframe_pts[j][i] = last_pts + A last_pts += A + B } last_pts is implicitly inited to zero. The first key_pts in the file really have a pts of zero, so 'A' needs to be zero, and still not be EOR. This patch fixes this... On another note, the 'prefix' (mpeg-4/mp3 startcode) is officially off the table? - ods15