[mythtv-users] HDMI sound issues

[Jean-Yves Avenard]

Hi

On 27 August 2013 15:25, Des Dougan <des at douganconsulting.com> wrote:
> I've just moved from an old TV to a flat-screen model (a Samsung); I've got picture but no sound (over HDMI).
>
> I've checked the digital audio how-to as far as I am able and have MythTV set to use the IEC device it sees, but with no sound.

I'm fairly certain that every guides written about digital audio on
the mythtv wiki are obsolete and should just be ignored totally.
If you want audio to come out of hdmi, you certainly don't have to
fiddle with any iec device.

>
> I'm now extremely confused and would appreciate any assistance the list can provide.
>
> My box is an old Acer Aspire desktop with an Azalia sound card on the motherboard; OS is OpenSUSE 11.4; TV Card is a Hauppauge 150; video is an nVidia GT220.

You do not need to do anything special.
You start mythfrontend, go into Setup -> Audio

there you'll see a list of devices available.

If you use a recent version of ALSA (>= 1.0.24), thing are even easier.

You haven't indicated if you want audio out via the hdmi pour or via
IEC (coax or optical)...

>
> aplay -L reports:
>
> # aplay -L
> null
>     Discard all samples (playback) or generate zero samples (capture)
> default:CARD=SIS966
>     HDA SIS966, ALC1200 Analog
>     Default Audio Device
> front:CARD=SIS966,DEV=0
>     HDA SIS966, ALC1200 Analog
>     Front speakers
> surround40:CARD=SIS966,DEV=0
>     HDA SIS966, ALC1200 Analog
>     4.0 Surround output to Front and Rear speakers
> surround41:CARD=SIS966,DEV=0
>     HDA SIS966, ALC1200 Analog
>     4.1 Surround output to Front, Rear and Subwoofer speakers
> surround50:CARD=SIS966,DEV=0
>     HDA SIS966, ALC1200 Analog
>     5.0 Surround output to Front, Center and Rear speakers
> surround51:CARD=SIS966,DEV=0
>     HDA SIS966, ALC1200 Analog
>     5.1 Surround output to Front, Center, Rear and Subwoofer speakers
> surround71:CARD=SIS966,DEV=0
>     HDA SIS966, ALC1200 Analog
>     7.1 Surround output to Front, Center, Side, Rear and Woofer speakers
> iec958:CARD=SIS966,DEV=0
>     HDA SIS966, ALC1200 Digital
>     IEC958 (S/PDIF) Digital Audio Output

if you want audio to come out of your spdif port out of the azalia
sound card; this is the device to choose in the list.
>From there, you can configure what your device support: AC3 / DTS, and
the number of speakers: stereo or 5.1

if you are running a recent-ish version of linux > 3.3 and < 3.8;
there are bugs in ALSA preventing spdif output to work while a hdmi
output is there.

so either upgrade your kernel, or downgrade if that's your case

> hdmi:CARD=NVidia,DEV=0
>     HDA NVidia, HDMI 0
>     HDMI Audio Output
> hdmi:CARD=NVidia,DEV=1
>     HDA NVidia, HDMI 0
>     HDMI Audio Output
> hdmi:CARD=NVidia,DEV=2
>     HDA NVidia, HDMI 0
>     HDMI Audio Output
> hdmi:CARD=NVidia,DEV=3
>     HDA NVidia, HDMI 0
>     HDMI Audio Output
>

> Clearly, the nVidia card is being seen as having a sound interface, though the card itself has no sound output other than the HDMI port.

the nvidia card *is* a sound card as far as linux/alsa is concerned.

> I've had both cards active in YaST and configured MythTV to use both the Azalia's IEC setting as well as the HDMI setting for the GT220 based on the various pieces of information I've found while researching this; however, no sound at all. I've also run mplayer and get no sound from there either, so it's not specifically a MythTV issue.

you can't configure myth to output to two devices at the same time.
There are ways, but that would involved playing with pulseaudio or
alsa configuration. You can't have digital audio working regardless if
you want multiple audio device at once.

so you need to decide which one you want to use: hdmi or spdif.

If hdmi, make sure you boot your PC *after* your TV has been turned on.
When you go into Audio setup, and you go through the devices, you'll
see the name of the device connected at the bottom; if you see the
name of your TV appearing there: this is the hdmi device to use.
This implies you have ALSA >= 1.0.24... If not, you'll have to go
through all hdmi devices listed, use the test screen and select one
that work.

JY