[mythtv-users] mythmusic iec958 help

Richard Shaw hobbes1069 at gmail.com
Tue Jul 1 02:03:36 UTC 2008


On Sun, Jun 29, 2008 at 12:48 PM, Alen Edwards
<allen.edwards at oldpaloalto.com> wrote:
>
>
> Gregg wrote:
>> I have mythmusic setup and can not get sound through iec958.  I have
>> followed this guide
>> http://www.mythtv.org/wiki/index.php/Configuring_Digital_Sound#Setting_up_ALSA.27s_.asoundrc.2C_Properly
>> but no dice.  If I run mplayer "musictitle.mp3"  -ao
>> alsa:device=iec958  it works fine, but if i use mythmusic I get
>>  2008-06-29 10:25:00.968 Opening audio device 'iec958'. ch 2(2) sr 44100
>> 2008-06-29 10:25:00.968 Opening ALSA audio device 'iec958'.
>> 2008-06-29 10:25:01.050 AudioOutput Error: Rate doesn't match
>> (requested 44100Hz, got 48000Hz)
>> 2008-06-29 10:25:01.050 AudioOutput Error: Unable to set ALSA parameters
>>
>> I have the sound device set to default in mythmusic.  Can someone tell
>> me if I am missing something?  I have a soundblaster live 5.1 card,
>> and below are the installed alsa apps.
>>
>> alsa-driver.i386                         1.0.16-65.fc8          installed
>> alsa-kmdl-2.6.24.4-64.fc8.i686           1.0.16-65.fc8          installed
>> alsa-lib.i386                            1.0.16-3.fc8           installed
>> alsa-lib-devel.i386                      1.0.16-3.fc8           installed
>> alsa-plugins-oss.i386                    1.0.15-3.fc8.1         installed
>> alsa-plugins-upmix.i386                  1.0.15-3.fc8.1         installed
>> alsa-plugins-vdownmix.i386               1.0.15-3.fc8.1         installed
>> alsa-tools.i386                          1.0.15-2.fc8           installed
>> alsa-utils.i386                          1.0.16-3.fc8           installed
>>
>>
>> Thanks.
>>
>> -Gregg
>>
> I think you need to set the sound to ALSA:iec958 and not default.  Not
> sure -- have not tried mythmusic.
>
> Allen

That will not work since the music files are at 44.1kHz and digital
requires 48kHz.

I assumed that you followed the wiki explicitly. If you look in the
suggested config file there is a section that tells you to uncomment
four lines.

Relevant section:
---
# Override the default output used by ALSA.  If you do not override the
# default, your default device is identical to the (unmixed) "analog" device
# shown below.  If you prefer mixed and/or digital output, uncomment the
# appropriate four lines below (only one slave.pcm line).
#
# Note, also, that as of ALSA 1.0.9, "software" sound cards have been modified
# such that their default "default" device is identical to the "mixed-analog"
# device.  Whether using an ALSA version before or after 1.0.9, it does no harm
# and has no affect on performance to redefine the device (even if the
# redefinition does not change anything).  Also, by using this ALSA
# configuration file, you once again have access to unmixed analog output using
# the "analog" device.
pcm.!default {
  type plug
## Uncomment the following to use (unmixed) "analog" by default
#  slave.pcm "analog-hw"
## Uncomment the following to use "mixed-analog" by default
  slave.pcm "dmix-analog"
## Uncomment the following to use (unmixed) "digital" by default
#  slave.pcm "digital-hw"
## Uncomment the following to use "mixed-digital" by default
#  slave.pcm "dmix-digital"
---

I chose to uncomment dmix-digital which works for me. I believe this
causes all 2 channel 44.1kHz sources to get resampled to 48kHz. Once
this is set you should set your default setting to "ALSA:default".

One side effect I've noted. The internal myth volume controls work
(i.e. [ & ]) but mute does not. It will actually show muted on the
screen but it doesn't work for me.

Richard


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