[mythtv-users] Audio issues - New Install

[Peter Bennett]

On 08/09/2017 02:09 PM, Ashu Desai wrote:
> I have a brand new install on CentOS 7.
>
> Backend is a VM and FE is on Zotac Ion
>
> When I open Alsammixer, i get the default one
>
> http://tinypic.com/r/2eldu9s/9
>
> I then press F6 and select the NVidia card
>
> http://tinypic.com/r/rli9ty/9
>
> However, if I press escape and go right back to alsamixer, it reverts 
> it back to the original one.
>
> lspci -vvnn reveals this for Audio:
>
> 00:08.0 Audio device [0403]: NVIDIA Corporation MCP79 High Definition 
> Audio [10de:0ac0] (rev b1)
>         Subsystem: PC Partner Limited / Sapphire Technology Device 
> [174b:437b]
>         Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- 
> ParErr- Stepping- SERR- FastB2B- DisINTx-
>         Status: Cap+ 66MHz+ UDF- FastB2B+ ParErr- DEVSEL=fast >TAbort- 
> <TAbort- <MAbort- >SERR- <PERR- INTx-
>         Latency: 0 (500ns min, 1250ns max)
>         Interrupt: pin A routed to IRQ 22
>         Region 0: Memory at fae78000 (32-bit, non-prefetchable) [size=16K]
>         Capabilities: <access denied>
>         Kernel driver in use: snd_hda_intel
>         Kernel modules: snd_hda_intel
>
>
> [mythtv at mythfe7 ~]$ aplay -l
> **** List of PLAYBACK Hardware Devices ****
> card 0: NVidia [HDA NVidia], device 0: ALC662 rev1 Analog [ALC662 rev1 
> Analog]
>   Subdevices: 1/1
>   Subdevice #0: subdevice #0
> card 0: NVidia [HDA NVidia], device 1: ALC662 rev1 Digital [ALC662 
> rev1 Digital]
>   Subdevices: 1/1
>   Subdevice #0: subdevice #0
> card 0: NVidia [HDA NVidia], device 3: HDMI 0 [HDMI 0]
>   Subdevices: 1/1
>   Subdevice #0: subdevice #0
>
> [mythtv at mythfe7 ~]$ aplay -L
> null
>     Discard all samples (playback) or generate zero samples (capture)
> pulse
>     PulseAudio Sound Server
> sysdefault:CARD=NVidia
>     HDA NVidia, ALC662 rev1 Analog
>     Default Audio Device
> front:CARD=NVidia,DEV=0
>     HDA NVidia, ALC662 rev1 Analog
>     Front speakers
> surround21:CARD=NVidia,DEV=0
>     HDA NVidia, ALC662 rev1 Analog
>     2.1 Surround output to Front and Subwoofer speakers
> surround40:CARD=NVidia,DEV=0
>     HDA NVidia, ALC662 rev1 Analog
>     4.0 Surround output to Front and Rear speakers
> surround41:CARD=NVidia,DEV=0
>     HDA NVidia, ALC662 rev1 Analog
>     4.1 Surround output to Front, Rear and Subwoofer speakers
> surround50:CARD=NVidia,DEV=0
>     HDA NVidia, ALC662 rev1 Analog
>     5.0 Surround output to Front, Center and Rear speakers
> surround51:CARD=NVidia,DEV=0
>     HDA NVidia, ALC662 rev1 Analog
>     5.1 Surround output to Front, Center, Rear and Subwoofer speakers
> surround71:CARD=NVidia,DEV=0
>     HDA NVidia, ALC662 rev1 Analog
>     7.1 Surround output to Front, Center, Side, Rear and Woofer speakers
> iec958:CARD=NVidia,DEV=0
>     HDA NVidia, ALC662 rev1 Digital
>     IEC958 (S/PDIF) Digital Audio Output
> hdmi:CARD=NVidia,DEV=0
>     HDA NVidia, HDMI 0
>     HDMI Audio Output
>
>
> Here's my /etc/asound.conf
>
> # Place your global alsa-lib configuration here...
> #
> pcm.!default {
>        type hw
>        card 0
>        device 3
>    }
> ~
> ~
>
> Under Mythfrontend Setup/Audio
> I have selected the ALSA:hdmi:Card=NVIDIA:DEV=0 that comes as option
>
> When you do "Test" - everything comes ok except sound for Center 
> (Comes off Surround Left) & Surround Left (swapped to Center)
>
> I also can't hear audio off quite a few movies, and when I check my 
> audio receiver shows input as PCM. The ones that have AC3 or DTS comes 
> out fine (although the sound coming off wrong speakers irks me)
>
> I am not hearing any TrueHD even though that is checked along with HBR 
> box that's checked by default
>
> I am giving data that I feel is needed so apologies if it's too much 
> or too little.
> .
>
> I am also hoping alsamixer can change default from PulseAudio to HDMI
> I can def give any other info that's required to solve this
>
>

Check your speaker configuration - 5.1 7.1 or stereo. This can affect 
which speaker the sounds come out of for PCM. You can try different 
values and see if anything works,

Is the audio passed to the sound system via HDMI? If there is a TOSLINK 
connection in there, that may affect things, because TOSLINK only 
supports 2 channels in PCM mode, so if it is sending more than 2 
channels they may get lost.

If AC3 and DTS is getting to the wrong speakers you must have something 
else going on, because the sound system itself will be sorting out which 
track goes to which speaker. (Speaker wires crossed?)

Note that the audio system test uses PCM sound. So you cannot test how 
AC3 will work that way. You say that the audio system test works but PCM 
movies don't work. That does not make sense.

If PCM does not work at all you can get past it by selecting "Upconvert 
stereo to 5.1 surround". That will convert PCM audio to Dolby Digital 
(AC3).


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