Audiogravity Guides

DSD on a Linux streamer: native, DoP, or converted to PCM

Short answer: DSD reaches a DAC in one of three ways. Native, as DSD itself. DoP, DSD wrapped in PCM words that the DAC unwraps. Or converted to PCM, which any DAC plays but which is no longer DSD. Native needs a USB DAC whose Linux driver exposes DSD. DoP needs a DAC that decodes it: one that does not receives PCM full of markers. And a DAC board on the Raspberry Pi's pins cannot take native DSD at all.

The three ways, as the DAC sees them

Measured on my test box (2026-10-17) with a DSD128 file and a USB DAC that accepts native DSD:

Sent as What the DAC receives (hw_params)
Native DSD format: DSD_U32_BE, rate: 176400
DoP format: S32_LE, rate: 352800
  • Native carries 32 bits of DSD per sample, so DSD128 needs 176.4 kHz and DSD256 352.8 kHz.
  • DoP carries 16 bits of DSD in each 24-bit word, the other 8 being the marker. So it needs twice the rate: 176.4 kHz for DSD64 and 352.8 kHz for DSD128 (the DoP standard), and 705.6 kHz for DSD256. On a card that stops at 384 kHz, like mine, DSD256 fits natively (352.8 kHz) but not as DoP (705.6 kHz).
  • Converted to PCM works with any DAC, at the cost of what DSD was chosen for.

What decides it on Linux

A USB DAC. The USB audio standard has no flag for "this device accepts DSD", so Linux keeps a list of the DACs known to, plus a generic detection that catches many others. The list grows with each kernel version: a recent DAC may need a newer kernel for native DSD. What your DAC accepts is one command away, with the DAC free and its card number in place of 0:

aplay -D hw:0,0 --dump-hw-params -d 1 -f S32_LE -r 44100 -c 2 /dev/zero

It plays one second of silence and lists what the card takes. Mine says FORMAT: S32_LE SPECIAL DSD_U32_BE and RATE: [44100 384000]: native DSD, PCM up to 384 kHz. A DSD_… format in that list means native DSD is possible.

A DAC board on the Pi's pins. The Pi's I2S drivers, on the Pi 4 and the Pi 5 alike, offer PCM only: 16, 24 or 32 bits, up to 384 kHz. Native DSD cannot pass. DoP can, if the board's chip decodes it, up to DSD128: 352.8 kHz fits under 384 kHz, the 705.6 kHz of DSD256 does not. Boards built on a chip that does not decode DSD, such as the PCM5122 of the HiFiBerry DAC+ Pro, play DSD only once converted to PCM.

MPD, which many Linux streamers play through, decides in this order: native when the card accepts it, DoP only if its dop option says yes (it has no way of knowing whether the DAC decodes DoP), and otherwise a conversion to PCM. One trap: dsd_usb is the name dop had until MPD 0.18, and MPD still reads it as the same option. With dsd_usb "yes", DSD leaves as DoP even beside dop "no": that is the pair behind the second row of the table above.

Roon decides with its own DSD Playback Strategy setting, Convert to PCM by default (see Roon on a Raspberry Pi).

Volume and DSD

A DSD stream cannot be turned down in software without converting it. On DoP, a digital volume would also alter the markers, and the DAC would no longer recognise DSD. Play DSD at full digital level and set your level on the amplifier, or on the DAC if it has its own volume.

With Audiogravity

From version 0.9.74, the configuration Audiogravity's guided setup writes for MPD leaves DoP off: DSD goes out natively to a DAC that accepts it, and MPD converts it to PCM for one that does not. Nothing reaches a DAC in a form it may not decode.

  • Boxes set up by an earlier version had DoP on, through the old dsd_usb line. The update removes that line where it sits beside dop "no", keeps the previous file among the configuration editor's saved copies, and restarts MPD.
  • A DAC that decodes DoP but not native DSD under Linux can still have DoP: set dop "yes" in MPD's file, from Config.
  • DSD plays at 100 on the box's own output. While a DSD track plays there, the volume is set to 100 and locked, then put back when the DSD ends.
  • Through HQPlayer, DSD is never converted behind your back. A file HQPlayer cannot read in DSD, a DST-compressed DFF, is refused with the reason.

The details are in the manual: Listening, and Outputs & engines → What can and cannot go through HQPlayer.

Sources