[mythtv-users] MythTV 0.24 HDMI audio problem

John P Poet jppoet at gmail.com
Tue Dec 7 05:33:30 UTC 2010

On Mon, Dec 6, 2010 at 7:19 AM, Jean-Yves Avenard <jyavenard at gmail.com> wrote:
> Hi Jarod
> On 20 November 2010 17:03, Jarod Wilson <jarod at wilsonet.com> wrote:
>> On Nov 19, 2010, at 8:05 PM, Jean-Yves Avenard wrote:
>>> On 20 November 2010 08:36, Jarod Wilson <jarod at wilsonet.com> wrote:
>>>> sure if its directly related or not, but scanning for audio
>>>> devices tends to always segfault on this box too. Same build
>>>> works just fine on an ion box.
>>> Great, can you put a backtrace on trac ?
>> Yeah, I should be able to do that this weekend. Is there a ticket already
>> opened that I should tack it onto, or shall I open a new one?
>>>> (nVidia 260.19.21 driver, ALSA 1.0.23 kernelspace and userspace).
>>> Did you try the last suggestion of using ALSA:hdmi:CARD=NVidia,DEV=x ?
>> Yep. Still no sound. Silence is NOT golden in this case... ;)
> Well, I received my new audio receiver for my cinema room.
> So the first thing I did was installed the GT220 card in the PC
> (identical one to my other machine)..
> Started.. and ... no sound
> I've finally tracked the issue.
> Following the steps I had written on how to achieve judder-free
> playback, I had totally overridden the EDID with Option "UseEDID"
> "false"
> Well, this is what caused no sound for me.
> I replaced it with:
>    Option "UseEDIDFreqs" "FALSE"
>    Option "UseEDIDDpi" "FALSE"
>    Option "ModeValidation" "NoEdidModes"
> (which according to nvidia is the same), and I get audio ...
> I guess UseEDID disables audio over hdmi as the nvidia drivers aren't
> able to check if the display supports sound.
> (note that without  Option "ExactModeTimingsDVI" "True" , one of my
> custom modelines were working)
> I thought you could be having the same issue
> Jean-Yves

I now have a HDMI equipped pre-amp, so now I am trying to get sound to
work.  Unfortunately, the EDID stuff does not seem to be my problem.

What is interesting, is that "aplay -l" lists three HDMI devices:

# aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: NVidia [HDA NVidia], device 3: NVIDIA HDMI [NVIDIA HDMI]
  Subdevices: 0/1
  Subdevice #0: subdevice #0
card 0: NVidia [HDA NVidia], device 7: NVIDIA HDMI [NVIDIA HDMI]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 0: NVidia [HDA NVidia], device 8: NVIDIA HDMI [NVIDIA HDMI]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 0: NVidia [HDA NVidia], device 9: NVIDIA HDMI [NVIDIA HDMI]
  Subdevices: 1/1
  Subdevice #0: subdevice #0

"aplay -L" just lists one:

# aplay -L
    Discard all samples (playback) or generate zero samples (capture)
    HDMI Audio Output

If I try to do "speaker-test -Dhdmi:CARD=NVidia" it says that it is
producing audio, but I don't hear anything.

If I add a bit to my /etc/asound.conf file:

pcm.nvidia_hdmi {
  type plug
  slave {
    pcm "hw:0,7"

pcm.!default nvidia_hdmi
pcm:iec958 nvidia_hdmi

Then *just* type "speaker-test", I *DO* get sound!  At this point, I
can use aplay to play wav files.

Note, that if I change the asound.conf file to have:
  pcm "hw:0,3"
Then I don't get any sound.  with "hw:0,7", "hw:0,8" and "hw:0,9" I
*do* get sound.

With that /etc/asound.conf, I tried telling myth to use "ALSA:default"
for it's audio device, but I still did not get any sound.

Then I tried changing Myth to use "ALSA:plughw:0,7", and I got sound,
but LCPM does not work (only bitstream).  So, I then tried the other

"ALSA:plughw:0,3"  - have sound
"ALSA:plughw:0,7"  - have sound
"ALSA:plughw:0,8" - have sound
"ALSA:plughw:0,9" - do not have sound ????

In none of the cases that actually produced sound, did LCPM work.  I
find it odd that in the asound.conf, it was device 0,3 that did not
work, and in Myth it seems to be device 0,9 that did not work --

Using the "ALSA:plughw" entries means that the asound.conf is not
necessary, but I am leaving it in the hopes that I can get flash audio

I would like to have LCPM working, but what I have will get me by for now.

A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?

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