[mythtv-users] OT: Probably dumb question about digital sound out
denier at umr.edu
Sun Sep 4 09:19:35 UTC 2005
On Sat, 2005-09-03 at 21:04 -0400, Ryan Steffes wrote:
> Digital audio is digital audio, correct?
Sort of. That is a lame answer, but sometimes going digital with the
audio makes things a bit more messy. To support all the fancy features
on your sound card your almost certainly going to need to use alsa,
which you should normally be by now anyway. It is also possible to
sometimes specify a specific port to output with using alsa like the
digital port. Here is the mplayer example for doing that. Of course
sometimes digital just works so ymmv.
-ao alsa commandline help:
Example: mplayer -ao alsa:mmap:device=hw=0.3
sets mmap-mode and first card fourth device
Set memory-mapped mode, experimental
Sets non-blocking mode
Sets device (change , to . and : to =)
> As in the the sound in the source defines the number of channels, not
> the hardware?
Well I've seen avi's have ac3 audio, and with a bit of work that can be
sent right out the port, and in my case make the pretty blue light come
on in my receiver for dolby digital sound. I'm sure dvd's are the same
kind of thing.
> I'm finally getting the stereo I want (I love my wife, best birthday
> present ever!) with digital in and all that, but my computer doesn't
> have digital out. I've had some motherboard wonkiness anyway, so I
> was considering just replacing the motherboard and getting one with
> digital out and a gigabit ethernet port, such as the ASUS A7N8X-E
I've got the same board and it is a good board. I've not tried much
with the audio on it though. If you already have a newer 2GHz + cpu
that is probably fine. If you have a sub 1Ghz cpu, then it might be a
grayer area as to what is best. This is a dual channel board, so, in
theory, if you put 2 matched memory sticks in the correct slots it will
help a little.
> The motherboard advertises as "6 Channels" which I assume they mean
> 5.1. My stereo is going to be 7.1, but the digital out on the
> motherboard will do just fine, right?
I'm not sure. I suspect if your just using your card to pass
precompressed audio from a video file it could, in theory, handle 7.1 or
whatever. Of course if the card says 5.1 then the best you could hope
for a game to generate is 5.1 and then its anyones guess if that would
be generated on the digital output. Perhaps someone else knows.
> There's not a difference on the digital side because it's a straight
> pass through, correct?
As a final note, it is worth noting that while a lot of dolby digital
things are cool and what have you, that much of what is on tv doesn't
support it, and sometimes rear speakers and such are just annoying. (I
haven't bothered to even connect mine.) It really kinda depends on what
you watch the most.
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