Andre Smagin: > There is possibly one more use case for "bit-perfect". I have a small > collection of surround sound (5.1, 4.1, quad, etc) recordings extracted > from various DVDs, SACDs, and other sources.
Yup. I even have a commercially released DTS-CD lying around somewhere, which is basically an ordinary CD except that the audio is encoded as DTS and not PCM. > My desktop is connected to a receiver via optical SPDIF cable. To get > the surround sound, I use mpd with 'device "snd/0"' option and Ario to > control the mpd daemon. I'm curious, what's the actual audio hardware? azalia(4) or uaudio(4)? > Bit depth does not seem to matter. I don't care about "bit-perfect", but > only about sending the dts stream to the receiver as-is, which works. S/PDIF actually has a native depth of 20 bits per sample. There are also 4 spare bits in the frame, which can optionally be used to transport 24 bits. If an audio source provides only 16 bits per sample, those are fit into the 20 bit frame with the remaining bits unused. DTS and AC3 encodings for S/PDIF only use 16 bits. -- Christian "naddy" Weisgerber na...@mips.inka.de
