In this paper a technique for generating consistent, reproducible traces with about an order of magnitude better compression than standard general-purpose compression programs is described. With this approach, the trace is read once, an intermediate form is generated and then read as the input to the second pass over the address stream. No program source code is required, and this technique will work on address streams that include OS calls. As a result of the way the address trace is encoded and processed, representing each reference requires only a fraction of a bit, between 0.00114 to 0.878 bits per reference. For example, the roughly 1.6 billion references generated by the xlisp benchmark from the SPEC92 suite can stored using only about 48.6 million bytes. Depending on the benchmarks, more or less bits per references may be needed.