Repository navigation
Conversation
…udio The C-Media "HIFI Decode Audio" USB device (0d8c:0089) exposes its analog DAC on PCM device 0 (USB interface 1, up to 768 kHz and DSD) and its optical S/PDIF output on PCM device 1 (USB interface 2, up to 192 kHz). Device 2 is the non-PCM alternate setting of the same S/PDIF endpoint. Without an entry here, iec958:CARD=... resolves to device 0, so the "Digital Stereo (IEC958)" output in PipeWire/PulseAudio plays through the analog jack and the optical output stays silent. Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com> Signed-off-by: Brian Kroth <bpkroth@gmail.com>
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
The C-Media "HIFI Decode Audio" USB device (
0d8c:0089) puts its optical S/PDIF output on PCM device 1, butUSB-Audio.confmapsiec958to device 0 unless the card is listed inUSB-Audio.pcm.iec958_device.As a result, the "Digital Stereo (IEC958)" output in PipeWire/PulseAudio plays through the analog jack and the optical output stays silent.
/proc/asound/cardN/stream*on this device:stream0(interface 1, PCM device 0): S16/S24/S32 plus DSD, 44.1 to 768 kHz. This is the analog DAC.stream1(interface 2, PCM device 1): S16/S24, 44.1 to 192 kHz. This is the optical S/PDIF output.stream2(interface 2, altset 3, PCM device 2): the non-PCM alternate setting of the same S/PDIF endpoint.Tested on Ubuntu 26.04 (alsa-lib 1.2.15.3, PipeWire 1.6.2, kernel 7.0).
speaker-test -D plughw:CARD=Audio,DEV=1plays through the optical output.With the same entry in
~/.asoundrc, the PipeWire IEC958 sink plays through optical too.🤖 Generated with Claude Code