From the OIV website

The OIV is an intergovernmental organisation of a scientific and technical nature of recognised competence for its works concerning vines, wine, wine-based beverages, table grapes, raisins and other vine-based products.

The role of the OIV aims to inform, assist, harmonise, standardise, and support the vitivinicultural sector. To achieve these goals, the OIV works through a network of over 1,000 experts from around the world. All final decisions of the OIV are made via consensus of the OIV member states. This work is for not only member states but also other international organisations and the vitivinicultural sector as a whole.

The principal function of the OIV is the creation of internationally harmonised and accepted standards for the production of vitivincultural products. These standards cover the entire production process and product lifespan, from the plantation of vines to the labelling of final containers. This work provides consistent international production standards1 for products of viticultural origin to ensure their international acceptance. Standards are adopted by consensus by OIV member states.

To learn more about OIV please visit: http://www.oiv.int/en/the-international-organisation-of-vine-and-wine/presentation-of-the-oiv.