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3gemail at gmail

Jun 29, 2008, 10:40 AM

Post #1 of 42 (1591 views)
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mythmusic iec958 help

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
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allen.edwards at oldpaloalto

Jun 29, 2008, 10:48 AM

Post #2 of 42 (1564 views)
Permalink

Re: mythmusic iec958 help [In reply to]

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
> _______________________________________________
> mythtv-users mailing list
> mythtv-users[at]mythtv.org
> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
>
>
I think you need to set the sound to ALSA:iec958 and not default. Not
sure -- have not tried mythmusic.

Allen
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3gemail at gmail

Jun 30, 2008, 2:53 PM

Post #3 of 42 (1530 views)
Permalink

Re: mythmusic iec958 help [In reply to]

> 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
>> _______________________________________________
>> mythtv-users mailing list
>> mythtv-users[at]mythtv.org
>> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
>>
>>
> I think you need to set the sound to ALSA:iec958 and not default. Not
> sure -- have not tried mythmusic.
>
> Allen

I have the default settings in mythv general setup as ALSA:iec958 with
ac3 and dts passthrough checked, and mythmusic generates the errors
posted before. Could it be something in my .asoundrc file? I have
been battling this for a couple of weeks now.

-Gregg
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mythtv at cox

Jun 30, 2008, 5:30 PM

Post #4 of 42 (1525 views)
Permalink

Re: mythmusic iec958 help [In reply to]

Gregg wrote:
>
> I have the default settings in mythv general setup as ALSA:iec958 with
> ac3 and dts passthrough checked, and mythmusic generates the errors
> posted before. Could it be something in my .asoundrc file? I have
> been battling this for a couple of weeks now.
>
>
>
I know very little about this, but if memory serves me you need to use
the asound file to tell alsa to resample from 44.1kHz to 48kHz or vice
versa. HTH.

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nick.rout at gmail

Jun 30, 2008, 6:01 PM

Post #5 of 42 (1524 views)
Permalink

Re: mythmusic iec958 help [In reply to]

On Tue, Jul 1, 2008 at 12:30 PM, Bob <mythtv[at]cox.net> wrote:
> Gregg wrote:
>>
>> I have the default settings in mythv general setup as ALSA:iec958 with
>> ac3 and dts passthrough checked, and mythmusic generates the errors
>> posted before. Could it be something in my .asoundrc file? I have
>> been battling this for a couple of weeks now.
>>
>>
>>
> I know very little about this, but if memory serves me you need to use
> the asound file to tell alsa to resample from 44.1kHz to 48kHz or vice
> versa. HTH.

By the look of the error message given that is indeed the problem.
Most digital audio decoders only work at 48000 (or 96000) Hz, whereas
the CD standard is 44100 Hz. It is indeed possible to get alsa to
resample, but don't ask me how off the top of my head. asound files
seem like a real black art to me, there are plenty of examples around
the intarweb, but no really simple documentation that I have been able
to find/understand about what is really going on.
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hobbes1069 at gmail

Jun 30, 2008, 7:03 PM

Post #6 of 42 (1520 views)
Permalink

Re: mythmusic iec958 help [In reply to]

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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allen.edwards at oldpaloalto

Jun 30, 2008, 8:00 PM

Post #7 of 42 (1519 views)
Permalink

Re: mythmusic iec958 help [In reply to]

Gregg 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
>>> _______________________________________________
>>> mythtv-users mailing list
>>> mythtv-users[at]mythtv.org
>>> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
>>>
>>>
>>>
>> I think you need to set the sound to ALSA:iec958 and not default. Not
>> sure -- have not tried mythmusic.
>>
>> Allen
>>
>
> I have the default settings in mythv general setup as ALSA:iec958 with
> ac3 and dts passthrough checked, and mythmusic generates the errors
> posted before. Could it be something in my .asoundrc file? I have
> been battling this for a couple of weeks now.
>
> -Gregg

I guess we have different versions as I don't have any asoundrc files.
I have a asound.conf file and I understand it that the system doesn't
need this file so if I were you, I would rename that file and see what
happens. It sounds to me like asla is trying to process the stream and
I don't think it should be.

Allen

allen.edwards at oldpaloalto

Jun 30, 2008, 8:04 PM

Post #8 of 42 (1519 views)
Permalink

Re: mythmusic iec958 help [In reply to]

Nick Rout wrote:
> On Tue, Jul 1, 2008 at 12:30 PM, Bob <mythtv[at]cox.net> wrote:
>
>> Gregg wrote:
>>
>>> I have the default settings in mythv general setup as ALSA:iec958 with
>>> ac3 and dts passthrough checked, and mythmusic generates the errors
>>> posted before. Could it be something in my .asoundrc file? I have
>>> been battling this for a couple of weeks now.
>>>
>>>
>>>
>>>
>> I know very little about this, but if memory serves me you need to use
>> the asound file to tell alsa to resample from 44.1kHz to 48kHz or vice
>> versa. HTH.
>>
>
> By the look of the error message given that is indeed the problem.
> Most digital audio decoders only work at 48000 (or 96000) Hz, whereas
> the CD standard is 44100 Hz. It is indeed possible to get alsa to
> resample, but don't ask me how off the top of my head. asound files
> seem like a real black art to me, there are plenty of examples around
> the intarweb, but no really simple documentation that I have been able
> to find/understand about what is really going on.
> _______________________________________________
> mythtv-users mailing list
> mythtv-users[at]mythtv.org
> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
>
>

I don't think he wants alsa to do anything. He has passthrough
checked. alsa should not be doing anything except passing the data to
the output. Something is telling alsa to process the data and the data
rates then become a problem. At least, that is my understanding of it.

Allen

nick.rout at gmail

Jun 30, 2008, 9:09 PM

Post #9 of 42 (1512 views)
Permalink

Re: mythmusic iec958 help [In reply to]

On Tue, Jul 1, 2008 at 3:04 PM, Alen Edwards
<allen.edwards[at]oldpaloalto.com> wrote:
>
>
>
>
> I don't think he wants alsa to do anything. He has passthrough checked.
> alsa should not be doing anything except passing the data to the output.
> Something is telling alsa to process the data and the data rates then become
> a problem. At least, that is my understanding of it.
>
> Allen

Well passing a 44.1kHz stream through to a decoder that wants a 48kHz
stream is not going to work AFAIK.

Unless I am misunderstanding how "passthrough" works.
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stevehodge at gmail

Jul 1, 2008, 6:37 AM

Post #10 of 42 (1491 views)
Permalink

Re: mythmusic iec958 help [In reply to]

On Tue, Jul 1, 2008 at 4:09 PM, Nick Rout <nick.rout[at]gmail.com> wrote:

> On Tue, Jul 1, 2008 at 3:04 PM, Alen Edwards
> <allen.edwards[at]oldpaloalto.com> wrote:
> > I don't think he wants alsa to do anything. He has passthrough checked.
> > alsa should not be doing anything except passing the data to the output.
> > Something is telling alsa to process the data and the data rates then
> become
> > a problem. At least, that is my understanding of it.
>
> Well passing a 44.1kHz stream through to a decoder that wants a 48kHz
> stream is not going to work AFAIK.
>

I doubt any modern decoder would fail to support both 48kHz and 44.1kHz,
however I do know that some sound cards can only generate one rate or the
other. That is why resampling via ALSA may be necessary.

Unless I am misunderstanding how "passthrough" works.
>

Passthrough means "if this signal is AC3 or DTS, don't decode, just
retransmit the original signal", but I believe the soundcard still needs to
be able to send the signal at the right rate.

Cheers,
Steve

joehenley at kc

Jul 1, 2008, 7:41 AM

Post #11 of 42 (1491 views)
Permalink

Re: mythmusic iec958 help [In reply to]

Gregg,

I assume (from the alsa file names) you're running Fedora Core 8. If
that's correct, then the first couple of "Info" boxes on the wiki you
reference are saying to NOT use a modified .asoundrc file. So go back
to the original from the FC8 distribution.

Also, are you using PukeAudio? If so, gert rid of it. It's still too
"bleeding edge" to use. (There are _lots_ of notes around about how to
do that.)

From your note, it sounds like you want to take the CDRom info, output
it thru the SPDIF connector to a separate amp/receiver/home theater
receiver/etc. If that's correct, then you want alsa plus the sound card
to do nothing to the signal; only stuff it into the SPDIF connector.
You want your receiver to decode and then push it to the speakers.

Most receivers these days, if they can handle (digital) SPDIF at all,
can figure out the underlying sample frequency (44.1KHz or 48 KHz), and
decode it correctly. The problem often comes when the sound card gets
in the middle and insists on re-coding the CDRom (native) signal as
being 48 KHz. The result is that the sound is then shifted upward in
frequency about 10% when the receiver decodes it.

Now the bad news. IIRC, most soundblaster cards cannot output a 44.1KHz
signal. So they code everything as 48KHz. I don't like Creative stuff
so I'm not familiar with the specifics of their cards these days. You
should be able to google "Soundblaster Live 5.1" and "bit perfect audio"
and get some useful info on your card's output capabilities. I fear you
may be in the market soon for a replacement card.

I had a similar problem awhile back and ended up getting a Turtle Beach
Riviera card. It was 20 or 30 bucks and "just works" in Linux.

Once you go back to the original .asoundrc file, get rid of PukeAudio,
get a soundcard which can output a proper 44.1KHz signal on the SPDIF
connector (or hopefully find a setting on SB Live card if possible),
then your MythTV settings above should be OK.

Good luck and come back here if you have questions.

Joe Henley

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allen.edwards at oldpaloalto

Jul 1, 2008, 8:07 AM

Post #12 of 42 (1491 views)
Permalink

Re: mythmusic iec958 help [In reply to]

Joe Henley wrote:
> Gregg,
>
> I assume (from the alsa file names) you're running Fedora Core 8. If
> that's correct, then the first couple of "Info" boxes on the wiki you
> reference are saying to NOT use a modified .asoundrc file. So go back
> to the original from the FC8 distribution.
>
> Also, are you using PukeAudio? If so, gert rid of it. It's still too
> "bleeding edge" to use. (There are _lots_ of notes around about how to
> do that.)
>
> From your note, it sounds like you want to take the CDRom info, output
> it thru the SPDIF connector to a separate amp/receiver/home theater
> receiver/etc. If that's correct, then you want alsa plus the sound card
> to do nothing to the signal; only stuff it into the SPDIF connector.
> You want your receiver to decode and then push it to the speakers.
>
> Most receivers these days, if they can handle (digital) SPDIF at all,
> can figure out the underlying sample frequency (44.1KHz or 48 KHz), and
> decode it correctly. The problem often comes when the sound card gets
> in the middle and insists on re-coding the CDRom (native) signal as
> being 48 KHz. The result is that the sound is then shifted upward in
> frequency about 10% when the receiver decodes it.
>
> Now the bad news. IIRC, most soundblaster cards cannot output a 44.1KHz
> signal. So they code everything as 48KHz. I don't like Creative stuff
> so I'm not familiar with the specifics of their cards these days. You
> should be able to google "Soundblaster Live 5.1" and "bit perfect audio"
> and get some useful info on your card's output capabilities. I fear you
> may be in the market soon for a replacement card.
>
> I had a similar problem awhile back and ended up getting a Turtle Beach
> Riviera card. It was 20 or 30 bucks and "just works" in Linux.
>
> Once you go back to the original .asoundrc file, get rid of PukeAudio,
> get a soundcard which can output a proper 44.1KHz signal on the SPDIF
> connector (or hopefully find a setting on SB Live card if possible),
> then your MythTV settings above should be OK.
>
> Good luck and come back here if you have questions.
>
> Joe Henley
Excellent post Joe. I ran across this wiki that goes into some detail
explaining how to find out if your sound card has a spdif passthrough
output. My card took until method 3 to find it.

http://alsa.opensrc.org/DigitalOut

I just want to second what Joe says. If ALSA is getting into the act,
change something until it isn't. If that takes a new sound card, get
it. The wiki should help you figure out what you need to do.

Allen

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nick.rout at gmail

Jul 1, 2008, 7:58 PM

Post #13 of 42 (1466 views)
Permalink

Re: mythmusic iec958 help [In reply to]

On Wed, Jul 2, 2008 at 2:41 AM, Joe Henley <joehenley[at]kc.rr.com> wrote:
> Gregg,
>
> I assume (from the alsa file names) you're running Fedora Core 8. If
> that's correct, then the first couple of "Info" boxes on the wiki you
> reference are saying to NOT use a modified .asoundrc file. So go back
> to the original from the FC8 distribution.
>
> Also, are you using PukeAudio? If so, gert rid of it. It's still too
> "bleeding edge" to use. (There are _lots_ of notes around about how to
> do that.)
>
> From your note, it sounds like you want to take the CDRom info, output
> it thru the SPDIF connector to a separate amp/receiver/home theater
> receiver/etc. If that's correct, then you want alsa plus the sound card
> to do nothing to the signal; only stuff it into the SPDIF connector.
> You want your receiver to decode and then push it to the speakers.
>
> Most receivers these days, if they can handle (digital) SPDIF at all,
> can figure out the underlying sample frequency (44.1KHz or 48 KHz), and
> decode it correctly. The problem often comes when the sound card gets
> in the middle and insists on re-coding the CDRom (native) signal as
> being 48 KHz. The result is that the sound is then shifted upward in
> frequency about 10% when the receiver decodes it.
>
> Now the bad news. IIRC, most soundblaster cards cannot output a 44.1KHz
> signal. So they code everything as 48KHz. I don't like Creative stuff
> so I'm not familiar with the specifics of their cards these days. You
> should be able to google "Soundblaster Live 5.1" and "bit perfect audio"
> and get some useful info on your card's output capabilities. I fear you
> may be in the market soon for a replacement card.
>
> I had a similar problem awhile back and ended up getting a Turtle Beach
> Riviera card. It was 20 or 30 bucks and "just works" in Linux.
>
> Once you go back to the original .asoundrc file, get rid of PukeAudio,
> get a soundcard which can output a proper 44.1KHz signal on the SPDIF
> connector (or hopefully find a setting on SB Live card if possible),
> then your MythTV settings above should be OK.
>
> Good luck and come back here if you have questions.
>
> Joe Henley

Nice post Joe, I think I have been confusing the abilities of my sound
card and the abilities of my surround sound system.

Thanks.
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3gemail at gmail

Jul 2, 2008, 3:33 PM

Post #14 of 42 (1425 views)
Permalink

Re: mythmusic iec958 help [In reply to]

>
> Gregg,
>
> I assume (from the alsa file names) you're running Fedora Core 8. If
> that's correct, then the first couple of "Info" boxes on the wiki you
> reference are saying to NOT use a modified .asoundrc file. So go back
> to the original from the FC8 distribution.
>
> Also, are you using PukeAudio? If so, gert rid of it. It's still too
> "bleeding edge" to use. (There are _lots_ of notes around about how to
> do that.)
>
> From your note, it sounds like you want to take the CDRom info, output
> it thru the SPDIF connector to a separate amp/receiver/home theater
> receiver/etc. If that's correct, then you want alsa plus the sound card
> to do nothing to the signal; only stuff it into the SPDIF connector.
> You want your receiver to decode and then push it to the speakers.
>
> Most receivers these days, if they can handle (digital) SPDIF at all,
> can figure out the underlying sample frequency (44.1KHz or 48 KHz), and
> decode it correctly. The problem often comes when the sound card gets
> in the middle and insists on re-coding the CDRom (native) signal as
> being 48 KHz. The result is that the sound is then shifted upward in
> frequency about 10% when the receiver decodes it.
>
> Now the bad news. IIRC, most soundblaster cards cannot output a 44.1KHz
> signal. So they code everything as 48KHz. I don't like Creative stuff
> so I'm not familiar with the specifics of their cards these days. You
> should be able to google "Soundblaster Live 5.1" and "bit perfect audio"
> and get some useful info on your card's output capabilities. I fear you
> may be in the market soon for a replacement card.
>
> I had a similar problem awhile back and ended up getting a Turtle Beach
> Riviera card. It was 20 or 30 bucks and "just works" in Linux.
>
> Once you go back to the original .asoundrc file, get rid of PukeAudio,
> get a soundcard which can output a proper 44.1KHz signal on the SPDIF
> connector (or hopefully find a setting on SB Live card if possible),
> then your MythTV settings above should be OK.
>
> Good luck and come back here if you have questions.
>
> Joe Henley
>
>
Thanks Joe. It is FC8 will try that tonight. Can't believe I missed
it. And I removed "PukeAudio" :) a while ago.

I will let you know if it works.

-Gregg
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3gemail at gmail

Jul 3, 2008, 9:54 AM

Post #15 of 42 (1394 views)
Permalink

Re: mythmusic iec958 help [In reply to]

Ok. I removed the .asoundrc file as suggested in the previous post.
It did not solve the problem. I even went as far as rebooting the pc.
Any other suggestions?

-Gregg
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hobbes1069 at gmail

Jul 3, 2008, 10:33 AM

Post #16 of 42 (1387 views)
Permalink

Re: mythmusic iec958 help [In reply to]

On Thu, Jul 3, 2008 at 11:54 AM, Gregg <3gemail[at]gmail.com> wrote:
> Ok. I removed the .asoundrc file as suggested in the previous post.
> It did not solve the problem. I even went as far as rebooting the pc.
> Any other suggestions?
>
> -Gregg

Well, this may not work, but it's worth a try. Sometimes you end up
trying stuff piecemeal and think you've tried everything but you
really have to do all of it together to make it work...

Copy the config file from the digital sound wiki verbatim and save it
as /etc/asound.conf (Might as well make it system wide).
use aplay -l to verify which device is iec958. For instance, on my
nForce3 FE/BE (and nForce4 desktop) MB it is card 0, device 2 instead
of card 0, device 1.
Make sure the mixed-digital entry in asound.conf is set to the correct
card/device.
Go into the mythmusic settings and set the audio output to ALSA:mixed-digital.
Reboot.

Let me know what happens...

Richard
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hobbes1069 at gmail

Jul 3, 2008, 10:35 AM

Post #17 of 42 (1395 views)
Permalink

Re: mythmusic iec958 help [In reply to]

On Thu, Jul 3, 2008 at 12:33 PM, Richard Shaw <hobbes1069[at]gmail.com> wrote:
> On Thu, Jul 3, 2008 at 11:54 AM, Gregg <3gemail[at]gmail.com> wrote:
>> Ok. I removed the .asoundrc file as suggested in the previous post.
>> It did not solve the problem. I even went as far as rebooting the pc.
>> Any other suggestions?
>>
>> -Gregg
>
> Well, this may not work, but it's worth a try. Sometimes you end up
> trying stuff piecemeal and think you've tried everything but you
> really have to do all of it together to make it work...
>
> Copy the config file from the digital sound wiki verbatim and save it
> as /etc/asound.conf (Might as well make it system wide).
> use aplay -l to verify which device is iec958. For instance, on my
> nForce3 FE/BE (and nForce4 desktop) MB it is card 0, device 2 instead
> of card 0, device 1.
> Make sure the mixed-digital entry in asound.conf is set to the correct
> card/device.
> Go into the mythmusic settings and set the audio output to ALSA:mixed-digital.
> Reboot.
>
> Let me know what happens...
>
> Richard
>

Oh, and sorry to reply to myself here, but don't forget to run
alsamixer (in a terminal) and make sure your iec958 entry is not
muted. If it is you need to unmute it by using the arrow keys to
highlight it and press "m". If this is the case you need to store the
changes using "alsactl store" or something like that.

Richard
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allen.edwards at oldpaloalto

Jul 3, 2008, 12:39 PM

Post #18 of 42 (1386 views)
Permalink

Re: mythmusic iec958 help [In reply to]

Gregg wrote:
> Ok. I removed the .asoundrc file as suggested in the previous post.
> It did not solve the problem. I even went as far as rebooting the pc.
> Any other suggestions?
>
> -Gregg
> _______________________________________________
> mythtv-users mailing list
> mythtv-users[at]mythtv.org
> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
>
>
I didn't seem to get a post that said to remove this file but in any
event you might try removing this one too:
/etc/asound.conf (actually, rename it just in case).

Allen

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joehenley at kc

Jul 3, 2008, 1:30 PM

Post #19 of 42 (1386 views)
Permalink

Re: mythmusic iec958 help [In reply to]

Gregg,

Hmmm. Do you still have the original .asoundrc file from FC8? I'm not
even sure there was one. Well, I'm reasonably sure running without any
.asoundrc is probably OK.

Richard's (hobbes1069) comments about alsamixer are right on. Make sure
all the iec958 stuff is unmuted, and set to some reasonably high volume
level. You can adjut them to your preferences later, once you know
which ones do what.

Now, are you getting anything from your receiver? Some of the indicator
lights ought to be lighting up to tell you what signals are coming thru.

If you are still getting the syslog errors about rate mismatches, then
at some point you're going to have to replace your sound card (to get
proper pitch on CDRoms). In the meantime, you might try setting the
sound device to /dev/dsp to see if it gets rid of the message; and/or
outputs sound.

Good luck,

Joe Henley
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nick.rout at gmail

Jul 3, 2008, 2:01 PM

Post #20 of 42 (1382 views)
Permalink

Re: mythmusic iec958 help [In reply to]

On Fri, Jul 4, 2008 at 8:30 AM, Joe Henley <joehenley[at]kc.rr.com> wrote:
> Gregg,
>
> Hmmm. Do you still have the original .asoundrc file from FC8? I'm not
> even sure there was one. Well, I'm reasonably sure running without any
> .asoundrc is probably OK.
>
> Richard's (hobbes1069) comments about alsamixer are right on. Make sure
> all the iec958 stuff is unmuted, and set to some reasonably high volume
> level. You can adjut them to your preferences later, once you know
> which ones do what.
>
> Now, are you getting anything from your receiver? Some of the indicator
> lights ought to be lighting up to tell you what signals are coming thru.
>
> If you are still getting the syslog errors about rate mismatches, then
> at some point you're going to have to replace your sound card (to get
> proper pitch on CDRoms).

This is a common theme. Do you know of a USB spdif card that supports
44.1kHz? Not all of us have space for more PCI cards!
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joehenley at kc

Jul 4, 2008, 6:52 AM

Post #21 of 42 (1342 views)
Permalink

Re: mythmusic iec958 help [In reply to]

Nick,

Sorry, no, I don't know of any USB solutions; doesn't mean there aren't
any. I just quit looking once I got my Riviera.

If it were me, I'd look first on Turtle Beach's web site (since I
_really_ like the Riviera card) and then I'd google for "USB, sound
card, spdif, and 44.1".

Good luck,

Joe Henley
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allen.edwards at oldpaloalto

Jul 4, 2008, 8:50 AM

Post #22 of 42 (1342 views)
Permalink

Re: mythmusic iec958 help [In reply to]

> This is a common theme. Do you know of a USB spdif card that supports
> 44.1kHz? Not all of us have space for more PCI cards!
One thing you might think about when you look is that the spdif spec
lists 48kHz but means anything up to that. You might find units listed
as 48KHz but if you look at them in detail find they will do what you want.

For example, I googled spdif usb and found this unit:
http://www.zzounds.com/item--BEHUCA202

If you look at the specs, you see this:
High-resolution 48 kHz converters for high-end audio quality

You could get discouraged but...

I then downloaded the manual and found this:
Digital Processing
Sample Rate: 32.0KHz, 44.1KHz, 48.0KHz

I am not recommending this store or brand. It was just the first one I
looked at. I recognize the brand as a good brand in professional audio
equipment (sound boards, speakers, etc).

Allen

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micke at smeddan

Jul 4, 2008, 3:26 PM

Post #23 of 42 (1325 views)
Permalink

Re: mythmusic iec958 help [In reply to]

Gregg, have you got this issue solved yet?
A working solution for FC8 with SB live 5.1 is just a one liner in
~/.asoundrc
echo "pcm.!default spdif" > ~/.asoundrc
and in mythv general setup: ALSA:*plug*:iec958

/Micke

Gregg wrote:
> Ok. I removed the .asoundrc file as suggested in the previous post.
> It did not solve the problem. I even went as far as rebooting the pc.
> Any other suggestions?
>
> -Gregg
> _______________________________________________
> mythtv-users mailing list
> mythtv-users[at]mythtv.org
> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
>

joehenley at kc

Jul 5, 2008, 8:22 AM

Post #24 of 42 (1287 views)
Permalink

Re: mythmusic iec958 help [In reply to]

Gregg,

From the posts above it doesn't look like it's going too well. I
continue to believe you will need to replace your sound card if you want
to get 44.1KHz signals into your receiver.

Have you checked the SoundBlaster site (or googled) for clarification on
what your specific card will do? Allen's comments above about
"sometimes spdif means upto 48KHz" is not 100%. Sometimes it's 48KHz
only; trust me, been there, done that. ... and paid the return shipping
for a limited capability card.

If your Soundblaster is not designed to output 44.1KHz via spdif, no
tweaking of alsa parameters, etc. will help.

If your particular SB model will support 44.1KHz, then remove .asoundrc
from /root , /home, and /etc, and anywhere else it resides. IIRC, you
have already removed PukeAudio, so from there you can start using
alsamixer to unmute the iec958 items.

The most common (from what I read on sites like this) successful MythTV
settings are:
Audio output device = ALSA: spdif
Passthru output device = Default
Max audio channels = stereo (The 5.1 setting is currently broken. Use
"stereo" and you'll still get 5.1 sound out of the system.)
Upmix = passive
Enable AC3 to SPDIF passthru = check
Enable DTS to SPDIF passthru = check
Enable internal volume controls = check
Mixer device = default
Mixer controls = Master

What will work for you is probably very similar to this. If this
doesn't work first time, then check the wiki for ways to determine good
alternatives to "Audio output device = ALSA: spdif". This setting seems
to have several different incantations; and seems to be the one most
people have to change.

Good luch, you _will_ eventually succeed,

Joe Henley
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fatgerman at ntlworld

Jul 5, 2008, 8:46 AM

Post #25 of 42 (1288 views)
Permalink

Re: mythmusic iec958 help [In reply to]

On Tuesday 01 July 2008 14:37:06 Steve Hodge wrote:
> On Tue, Jul 1, 2008 at 4:09 PM, Nick Rout <nick.rout[at]gmail.com> wrote:
>
> > On Tue, Jul 1, 2008 at 3:04 PM, Alen Edwards
> > <allen.edwards[at]oldpaloalto.com> wrote:
> > > I don't think he wants alsa to do anything. He has passthrough checked.
> > > alsa should not be doing anything except passing the data to the output.
> > > Something is telling alsa to process the data and the data rates then
> > become
> > > a problem. At least, that is my understanding of it.
> >
> > Well passing a 44.1kHz stream through to a decoder that wants a 48kHz
> > stream is not going to work AFAIK.
> >
>
> I doubt any modern decoder would fail to support both 48kHz and 44.1kHz,
> however I do know that some sound cards can only generate one rate or the
> other. That is why resampling via ALSA may be necessary.
>
> Unless I am misunderstanding how "passthrough" works.
> >
>
> Passthrough means "if this signal is AC3 or DTS, don't decode, just
> retransmit the original signal", but I believe the soundcard still needs to
> be able to send the signal at the right rate.

This may not be relevant, but I used to use a soundblaster Live under Windows (with Steinberg ASIO drivers). The Emu10k1 chip on which it is based can only run at 48KHz and will only output 48KHz via its spdif. (It will, however accept 44.1KHz input signals, I'm not sure how it manages that). In your case, it's very possible that ALSA is assuming that the chip requires 48KHz and will not send it anything else. In that case your only option may be to try simply switching passthrough off and allow some resampling to happen.

Mark

>
> Cheers,
> Steve
>

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