Audio over HDMI

From LinuxMCE
Jump to: navigation, search
Version Status Date Updated Updated By
710 Unknown N/A N/A
810 Deprecated- Use Unmuting_Channels Only 10 october 2010 golgoj4
1004 Unknown N/A N/A
1204 Unknown N/A N/A
Usage Information

(Also see notes on the LinuxMCE-0810 alpha2 page)

That article is started to help people get audio over HDMI. Feel free to post here your experience!

Generally it's possible with kernel 2.6.27 and ALSA 1.0.18. A few notes here. First of all, note that DVI port support video signal only. It's possible to inject audio signal to external video card from the S/PDIF using SPDIF_HDMI headers. Usually integrated video card with HDMI port have possibility to pass audio as well.

nVidia

Card provided devices

nVidia doesn't provide a separate card for HD. Instead of that it offers a separate device:

linuxmce@dcerouter:~$ aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: NVidia [HDA NVidia], device 0: ALC883 Analog [ALC883 Analog]
 Subdevices: 1/1
 Subdevice #0: subdevice #0
card 0: NVidia [HDA NVidia], device 1: ALC883 Digital [ALC883 Digital]
 Subdevices: 1/1
 Subdevice #0: subdevice #0
card 0: NVidia [HDA NVidia], device 3: NVIDIA HDMI [NVIDIA HDMI]
 Subdevices: 1/1
 Subdevice #0: subdevice #0
linuxmce@dcerouter:~$ aplay -L
default:CARD=NVidia
   HDA NVidia, ALC888 Analog
   Default Audio Device
front:CARD=NVidia,DEV=0
   HDA NVidia, ALC888 Analog
   Front speakers
surround40:CARD=NVidia,DEV=0
   HDA NVidia, ALC888 Analog
   4.0 Surround output to Front and Rear speakers
surround41:CARD=NVidia,DEV=0
   HDA NVidia, ALC888 Analog
   4.1 Surround output to Front, Rear and Subwoofer speakers
surround50:CARD=NVidia,DEV=0
   HDA NVidia, ALC888 Analog
   5.0 Surround output to Front, Center and Rear speakers
surround51:CARD=NVidia,DEV=0
   HDA NVidia, ALC888 Analog
   5.1 Surround output to Front, Center, Rear and Subwoofer speakers
surround71:CARD=NVidia,DEV=0
   HDA NVidia, ALC888 Analog
   7.1 Surround output to Front, Center, Side, Rear and Woofer speakers
hdmi:CARD=NVidia,DEV=0
   HDA NVidia
   HDMI Audio Output
null
   Discard all samples (playback) or generate zero samples (capture)

Correct LSPCI Output

If you don't see HDA NVidia in the aplay -L output that means you card is not recognized by system correctly. Here is a correct output of lspci:

lspci -v
(only the relevant portion):
00:07.0 Audio device: nVidia Corporation MCP78S [GeForce 8200] High Definition Audio (rev a1)
Subsystem: ASUSTeK Computer Inc. Device 82fe
Flags: bus master, 66MHz, fast devsel, latency 0, IRQ 20
Memory at fcf78000 (32-bit, non-prefetchable) [size=16K]
Capabilities: <access denied>
Kernel driver in use: HDA Intel
Kernel modules: snd-hda-intel

Unmuting Channels

From the command line, type the following

alsamixer

The alsamixer should should display three digital devices:

  • IEC958
  • IEC958 D
  • ICE9581.

All of them should be unmuted. Press 'm' to unmute, and the right and left arrows to navigate. Then select 'HDA NVidia NVIDIA HDMI (ALSA)' as output for all items in 'Sound Prefrences' and select 'HDA NVidia (Alsa mixer)' as the mixer.

After that audio over HDMI should work.

The Wrong way

This is an example of doing things the wrong way and potentially screwing things up for other users. asound.conf will be overwritten on reboots, making it less than ideal. Please contact someone in irc and verify information like this before its added to the wiki. -golgoj4

EDITED (geekyhawkes)  It might be necessary to create an /etc/asound.conf file to "forward" the audio to your HDMI port.  Details of the asound.conf file i am using can be found here[1]

Test

To test your HDMI output run following command:

aplay -D plug:hdmi /usr/share/sounds/KDE_Window_Open.wav

Replace KDE_Window_Open.wav by any other WAV file. You should use plug to convert mono sample to stereo.

ATI

Usually integrated ATI video cards come with separated HD sound card (for example, integrated ATI RadeonTM 1250). Sound over HDMI works fine with the latest Catalyst drivers.

See Also