[mythtv-users] mythmusic iec958 help

Alen Edwards allen.edwards at oldpaloalto.com
Sun Jul 6 05:35:57 UTC 2008


Rich West wrote:
> Joe Henley wrote:
>> 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,
> For more information, check out:
> http://www.mythtv.org/wiki/index.php/Configuring_Digital_Sound_with_AC3_and_SPDIF
> 
> That page will walk you through what steps to take to:
> o get spdif sound working with linux (Fedora) - something you already 
> have working
> o get the configuration set up to work with Myth (and MythVideo) for 5.1 
> and stereo output - something you already have working
> o and get the configuration set up to work with MythMusic - the piece 
> you are trying to get working
> 
> More than likely, you're using a system with on-board SPDIF 5.1 
> surround.. if that is the case, then it should be able to be done (and 
> if it is AC97 chipset based, it is definitely possible).
> 
> The key piece to get MythMusic working when you have all of the other 
> components working is by setting "Max audio channels = stereo".
> 
> -Rich

That wiki is good.
Just don't get distracted with this one:
http://www.mythtv.org/wiki/index.php/Configuring_Digital_Sound
It doesn't work.

Allen


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