[mythtv-users] AC3 and/or S/PDIF (again)

[Ben Suffolk]

>> A quick question if I may. Am I right in thinking that if I buy a  
>> new sound-card with 6 analogue channels on the output it will  
>> drive my 5.1 amp (it has 6 channel input) for surround sound.
> Yes (assuming you mean by 6-channel input that you have at least 6  
> RCA connectors or 3 headphone connectors for input).

Yes, thats what I meant, it has 6RCA connectors for direct 6 channel  
input


> Note, though, that many cards use line in for surround output in  
> surround modes, so if you've got a software encoder that requires a  
> sound card for audio, you may have to keep your on-board card  
> enabled as well for sound capture.

No problem there, I am using DVB-T cards, so all audio comes in the  
mpeg2 stream.

>> Does it also work happily with the internal volume controls as  
>> well (which after all is what I am trying to achieve)
> That's a question of your ALSA drivers.  For some, the Master  
> controls only 2-channel audio and has no effect on surround  
> channels (i.e. your front left/right will get quieter and your  
> center/rear channels will stay at full volume).  Since Myth's  
> internal volume controls can only use either PCM (which is always 2- 
> channel audio) or Master (which is sometimes 2-channel audio), you  
> may be forced to use an external script to change volume (thereby  
> losing the OSD volume indicator).  However, using the mythtvosd  
> program, you can make a "poor-man's" volume OSD.

Ok so are there known working ALSA drivers? Since I am going to buy a  
new sound-card I may as well buy one that we know the ALSA drivers do  
indeed reduce the volume on all speakers when the master is faded. If  
anybody has this kind of setup and knows the master fades all  
channels please let me know what sound-card you have.

Thanks for the tip with the mythosd app, that looks interesting for  
other things.

Regards

Ben