Digital Output Bit Depth
Digital output bit depth is the greatest PCM word length a product can send through a specified digital output.
Word length describes how many bits represent each PCM sample. An output's supported depth is a compatibility limit, not proof that every recording contains that much useful resolution. Input support and internal processing precision can be different from output capability.
Digital Output Bit Depth — Digital Interface
A digital interface may accept one PCM word length and send another through its outputs. An I²S connection, for example, can have a different limit from S/PDIF or AES/EBU. This matters when using the interface between a source and a DAC, because both sides of the output link must agree.
Compare the maximum for the output actually used, together with its supported sample rates. Internal DSP precision is not an output word length, and upsampling cannot recreate detail absent from the source. A figure without an identified connection should not be assumed to apply equally to every socket.
Digital Output Bit Depth — Streamer
A streamer's file decoder may handle a greater word length than a particular digital output can transmit. The output specification determines what can be passed to an external DAC on that connection. USB, optical and coaxial outputs may therefore have different limits even when they play from the same library.
Compare the selected output with the DAC's input capability, checking sample rate as well as bit depth. Network playback support or a file-format maximum does not establish the transmitted word length. Volume processing may also affect the signal, so a high supported depth alone does not prove an unchanged transfer.
Digital Output Bit Depth — DAC
A DAC may include a digital output for onward connection as well as analogue outputs. This field describes the PCM signal it can send onward, not the resolution of its conversion chip. Pass-through and processed digital outputs can have different capabilities, so the output's function matters.
Compare the documented digital output and the receiving device's input limits, including the supported rate at that word length. A '32-bit DAC' label describes neither every output nor the analogue system's effective resolution. DSD's one-bit coding is a different format and does not replace a PCM output-depth specification.