Wireless communications typically feature narrow-bandwidth, error-prone and are more vulnerable than the wired counterparts. Numerous packet based stream authentication schemes are proposed for authenticating stream transmitted over erasure wireless channel. However, by fixing the packets in transmission, any packet manipulation will cause authentication failure. In this paper, we assume a more flexible scenario where a gateway, between a producer and a receiver, is able to make adaptation operations over a stream to better fit in the wireless channel. Our adaptive scheme enables packet manipulation by committing the changes, while previous schemes are simply unapplicable. We elaborate the adaptive authentication scheme based on layered structure of a video stream as well as its encoding, packing, amortizing and verifying methods in this paper. The security is analyzed in terms of authentication probability, in which higher authentication rate (95%) is achieved with less overhead per packet. The performance analysis show that our scheme reduces more than 56% of the overhead per packet compared with that of packet based schemes.