b18f8cbf3d
Revert "swscale: update context offsets after removal of AlpMmxFilter." (commita95e3fa90b) and Revert "swscale: Remove some write-only variables related to alpha handling." (commit9d03cb9fc5). They broke alpha handling - it's the evil inline asm that still uses that variable, so it's not truely write-only.