Marriage is not a joke but very serious part of life. The marriage in India are solemnized either according to the religious rites, customs and ceremonies of the parties like for Hindus according to Hindu Marriage Act,1955 etc. or by civil form under the Special Marriage Act,1954 where two persons of any religion can get married by the marriage officer/registrar.
When two people without going through any religious rites, custom and ceremonies to which they both belong just declare they got married than that will not be taken to be valid marriage between both of them. The marriage has to be solemnized by the religious priest and in presence of members of the society by prescribed religious rites, customs and ceremonies than only that can be said to be valid marriage in the eye of law. The religious marriages too are supposed to be registered with the Registrar of Marriages according to the State Marriage Registration Acts. The Hindu Marriages usually get registered under the Hindu Marriage Act, 1955. Whereas Christian Marriages get solemnized according to the Indian Christian Marriage Act, 1872 and registered under this Act by the priest who issues marriage certificate to parties. The Muslim Marriages get solemnized by the Qazi and even registered by such person who issues marriage certificate or Nikahnamma to parties. And even for any other religion in India. The parties for religious marriage have to be of same religion only than it will be valid religious marriage between them.
Over all the marriage said to be done on admission by parties only, without any witnesses, no priest, no family members or friends to state before any authority the actual solemnization of complete marriage between parties according to rites, customs and ceremonies of the parties, no photographs and video recording of the marriage ceremonies and no registration with the Registrar of Marriages, will not be considered as marriage at all for any purposes. The parties even though admitted about the solemnization of marriage is recorded won't make much difference if there was no such marriage solemnization that ever took place.