Recirculating special effects video framestore

摘要

A video special effects mixer including an improved recirculating frame store is disclosed. The mixer receives several inputs one of which is from the recirculating frame store and provides several outputs one of which goes to the recirculating frame store. The recirculating frame store includes two field recirculation loops and an interpolator. The real field is mixed with the previous interpolated recirculated field and the interpolated field is mixed with the previous real recirculated field. The output alternates between the two mixed fields. The recirculating frame store receives a key signal indicating relative gain, and has a key processor that reduces the gain of the recirculating key such that the combined gain is no more than unity.