[FAQ] What is DoP (DSD over PCM)?

The original idea for DoP was invented by dCS in 2011. It involves taking groups of 16 adjacent 1-bit samples from a DSD stream and packing them into the lower 16 bits of a 24/176.4 data stream. Data from the other channel of the stereo pair is packed the same way. A specific marker code in the top 8 bits identifies the data stream as DoP, rather than PCM. The resulting DoP stream can be transmitted through existing 24/192-capable USB, AES, Dual AES or SPDIF interfaces to a DoP-compatible DAC, which reassembles the original stereo DSD data stream COMPLETELY UNCHANGED.

If something goes wrong and the data stream is decoded as PCM, the output will be low-level noise with faint music in the back ground, so it fails safely. This can happen if the computer erases the marker code by applying a volume adjustment.