Now you point it out, you're right++.

I got hung up on the "64 characters" bit and completely forgot that the input to the encoding process can contain any byte values.

That said, I still much prefer length prefixing (via pack 'n/a*' etc.) which also allows the data packet to contain all byte values, but has the added advantages of:

• 4(or 2 or 1)-bytes/per packet transmission overhead rather than 37%.
• Negligible encoding/decoding overhead.
• The ability to read for just what is required rather than rely on buffering and buffer management.