Replace the __ to %

hi all ,

I have a problem about rewrite

location ~ (.ts)$ {

}

req
http://127.0.0.1/__ce__a3__c7__e9__b5__fd__d5__bd(1080P__bb__ad__d6__ca).ts

I need to replace __ to %
http://127.0.0.1/Σ����ս(1080P����).ts

How to design the “rewrite” cmd?

THX

Best Regards,
Harold Miao