Streamer output limited by on board DAC?

[ex audiophile]

I'm struggling to find a streamer that outputs hi res and I'm wondering if the figures published by the manufacturers refer to the analog output or the digital? For example the Sonos Port appears to support up to 24/45 output; but their site does not say if this output is from their analog output, using the built in DAC. If you use the digital out does it just pass on the digital stream unchanged? If you're using a hi res service and want 24/192 can you get that from the digital out?