DSD over PCM (DoP)
One of the biggest drawbacks of DSD modulation as audio format is non-existent physical interface for consumer products. Professional products sometimes have a SDIF3 interface, where left, right and clock signals are transmitted separately. To transmit DSD data between two consumer audio devices, for example between a computer and a stand-alone DAC, a method of packing DSD data into PCM frames has been developed. We won’t go into too much detail here, specifications and further details can be found online, for instance here: https://dsd-guide.com/dop-open-standard. An interesting fact is, that in the past we used an almost identical principle to capture raw DSD data from a SACD player for off-line processing, just without the header and with data aligned differently, years before the standard was created.
Synchronization and muting detection
Not being extremely complex, a DoP decoder can be easily and seamlessly integrated into existing products to add support for DSD playback via DoP, potentially together with a DSD to PCM conversion core. A DoP encoder is useful when a raw DSD bus is available, for instance in professional equipment, and this way it can be connected to a consumer grade device with a DSD/DoP interface.