The rite and formulas for the sacrament of penance are to be revised so that they more clearly express both the nature and effect of the sacrament.
Sacrosanctum Concilium, 72
The description is given by those who posted the video, so we merely translate this peculiar innovation:
"In the course of the Eucharist with Children, the Confession of sins was not auricular, but each person previously wrote his sins on a piece of paper and then, in the Celebration, the Priest, after reading each, granted absolution to all those who confessed. They were mostly Children, Teenagers, and young adults joined this initiative, but also many adults followed on the steps of the young. While the priest, Father Julio Grangeia, read the sins, the Arcel choir, of the Parish of Espinhel (Deanery of Agueda, Diocese of Aveiro, Portugal) sang penitential chants in order to create a more appropriate environment."
Upon reading the sins (not out loud!), the reverend Father took great care with the seal of confession by feeding the pieces of paper to a paper shredder nearby: it beautifully "expresses", in a "revised" way and "more clearly", "the nature and effect of the sacrament," as the Council asked, so we guess it is a welcome innovation. The liturgical chanting is particularly moving: what sinner does not feel like a stone, rolling down a hill, as tears go by? (Tip: Fratres in unum)