I have a frame of 480 bytes in which I have a sync word of 10 bits long. I need to be able to find the start of my framing which may not occur on a byte boundary. I also have to take into consideration that the file may skew occationally, so I'd have to check frame by frame for my sync word. I've done this successfully using pack and unpack but it takes forever. I would like to slide through the file without having to pack or unpack.