[mythtv-users] I thought I understood HDMI audio, but...

Don Brett dlbrett at zoominternet.net
Mon Jun 28 02:08:52 UTC 2010

Christopher Kerr wrote:
> On Mon, Jun 28, 2010 at 7:51 AM, Don Brett <dlbrett at zoominternet.net> wrote:
>> I just bought a Vizio E421VA at Sams, and I'm having trouble understanding
>> the HDMI and audio parts.  I thought the video signal was on the HDMI cable
>> and the audio was on a separate audio cable (rca connector style). As I
>> understand it, integrated video and audio on HDMI is just  happening now
>> with some of the  latest nvidia boards.
> Nope, HDMI audio is always digital, and is multiplexed with the video
> signal. I have no idea where the separate wires myth comes from,
> although it's surprisingly popular.
> Some older graphics cards have a header that allows a SPDIF output
> from your soundcard to be muxed with the DVI/HDMI video, whilst newer
> ones have an integrated sound device.
> Some TV's do allow for another audio source to be used with the HDMI
> inputs, but it's probably not set up that way by default - there's
> usually a setting ("Audio Source", "Sub-Input" or something of the
> like) to enable it. At any rate, it's got nothing to do with the HDMI
> implementation.
> - Chris
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Thanks Chris, that was pretty good; I didn't realize the two streams 
were multiplexed, but I guess that makes sense...it is mpeg.  I was also 
hoping to figure out how to do this.

I got the definite impression that most people did the two cable thing.  
If you don't use two cables, how do you get the audio onto the HDMI?  I 
thought it was just recently added into ALSA, so how did mythtv users do 
it before that?

To add one complication, the new TV has the two cable method show in the 
manual, pairing the "HDMI input #2" and the "PC audio input"  together, 
but it doesn't seem to work.  I may find that the multiplexed method is 
my only choice.  Suggestions?

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