[mythtv-users] HDMI and audio

[Jim Stichnoth]

On Wed, Nov 18, 2009 at 4:21 PM, Patrick Doyle <wpdster at gmail.com> wrote:
> On Wed, Nov 18, 2009 at 6:48 PM, Jim Stichnoth <stichnot at gmail.com> wrote:
>> On Wed, Nov 18, 2009 at 3:31 PM, Patrick Doyle <wpdster at gmail.com> wrote:
>>> a few days ago (see
>>> http://www.gossamer-threads.com/lists/mythtv/users/406672) in which a
>>> user was having difficulties getting HDMI audio to work with his Vizio
>>> TV.   (Gee, I've got a Vizio TV as well.)
>>
>> The poster in that thread was talking about a Vizio TV with a DFP
>> interface, which is different from HDMI.
>
> OK, now I'm really confused...
>
> a) What is a DFP interface?
>
> b) I read "I have a Vizio DFP TV that I conect to my mythtv system using HDMI
> (adapter) from a Nvidia 8600GT using DVI".  So I thought that meant OP
> was connecting via an HDMI connector on the TV.

I don't really know anything about DFP, but Wikipedia indicates it's
an interface along the lines of HDMI or DVI.  I assume the OP wanted
to connect a DFP TV to an HDMI nVidia card.

>> In the end, my audio problem was because the Vizio's EDID
>> over HDMI doesn't offer a setting at the panel's native resolution,
>> and I was overaggressively telling the driver to ignore the EDID to
>> the point where the driver didn't think the TV had audio-over-HDMI
>> capability.
> ok... after this afternoon's research session, those words all make
> sense to me, and gives me some clues for things to try should I run
> into a similar problem.
>
> Of course, the problem with the words making sense, is that now I'm
> going to try to have the concepts make sense...
>
> What do you mean by saying that " the Vizio's EDID over HDMI doesn't
> offer a setting at the panel's native resolution"?  For the sake of
> example, I'm going to assume that you have a 1080p Vizio (since that's
> what I have).  Are you saying that the EDID did not report 1920x1080?

According to the manual, the panel's native resolution is 1366x768.
This resolution is readily available using the VGA connector.  But if
you connect it to the computer via HDMI, that resolution is not
reported.  You can choose 1280x720 (i.e. 720p), but in addition to
having the TV rescale the picture, it also "helpfully" adds overscan.
It is possible to get the native 1366x768 resolution over HDMI using a
custom Modeline, but, as I said earlier, you have to be not too
aggressive in telling the driver to ignore the EDID, otherwise you may
lose audio.

Jim