- This Recommendation specifies a coded representation that can be used for compressing the moving picture component of audio-visual services at low bit rates. The basic configuration of the video source coding algorithm is based on ITU-T Rec. H.261. Eighteen negotiable coding options are included for improved performance and increased functionality. This Recommendation contains Version 2 of ITU-T Rec. H.263, which is fully compatible with the original Recommendation, adding only optional features to the original Version 1 content of the Recommendation.