[mythtv-users] HDMI keep alive, maybe via sending silent audio?

[Mike Perkins]

On 16/05/16 11:01, John Veness wrote:
> On 16/05/2016 10:03, Simon Hobson wrote:
>> John Veness <John.Veness.mythtv at pelago.org.uk> wrote:
>>
>>> The soundbar has several sockets, including analogue audio inputs, optical input, Bluetooth
>>> input, 3 HDMI inputs and one input/output socket for HDMI ARC, the latter of which plugs into the
>>> TV.
>>>
>>> The HDMI ARC socket is used as an output when HDMI 1, 2 or 3 are selected as the current input on
>>> the soundbar - the soundbar will play the audio directly from the HDMI 1, 2 or 3 input, and pass
>>> the signal onto the HDMI ARC socket for display on the TV. So the soundbar can be used as a
>>> switcher as well as speakers, if you run out of HDMI sockets on the TV.
>>>
>>> The HDMI ARC socket can also be selected as an input on the soundbar itself, in which case it
>>> will play whatever sound the TV is generating, for sources plugged into the TV itself, or when
>>> using the TV built-in tuner, or smart facilities.
>>>
>>> According to the soundbar manual, by design it will go to sleep after a few minutes of silence on
>>> the currently selected input. This certainly seems to be the case when the analogue audio inputs
>>> are used.
>> Can it be set to only use the ARC audio channel - even when switching one of the HDMI inputs to
>> the TV ?
>> If not, then that's as carp a design as not being able to not sleep on lack of sound. What if
>> someone connects a computer that doesn't do sound out via DVI - my laptop annoying comes from just
>> before Apple started outputting audio to the mini-displayport ?
> The soundbar (a Maxell MXSP-SB3000)**was nice and cheap, gives good sound, and has a nice lot of
> inputs, but is otherwise not very configurable, so unfortunately it doesn't allow configuring to
> always take the audio from the HDMI ARC socket, independent of the HDMI switching capability. (It
> also doesn't accept discrete power off and power on commands, which makes programming a universal
> remote annoying).
>
> Regardless of the "going to sleep" problem, I wish it could be made to always take audio from HDMI
> ARC, because something I haven't mentioned is that when it plays the audio directly from the HDMI
> input socket and passes the picture onto the TV via the HDMI ARC socket, the audio comes out
> slightly before the picture, presumably due to image processing delays on the TV. When the TV sends
> the audio out of its HDMI ARC socket, it seems to do so with no delay. Luckily, with Myth at least
> (maybe not other sources) the audio can be set to be delayed, to counteract that.
>
> It may be that one solution would be to ignore the three other HDMI inputs on the soundbar and use a
> separate HDMI switcher, plugged into a separate HDMI socket on the TV, and use the TV's HDMI ARC
> output to the soundbar, which experimentation is showing that it would not sleep on silence.
>
> But that does seem a waste of money, waste of power, another remote to deal with, or push me over
> the limit of number of devices I can program into my universal remote. Especially as the soundbar
> *can* do HDMI switching, and *can* seemingly not sleep when my Roku or PS3 is plugged into it, even
> when those devices are paused or in menus.
>
> I'm sure there is a solution, presumably by playing a "silent" WAV file on a loop. I'm not sure if
> I'd be able to play that all the time, and have Myth's audio output mixed into it, or whether I
> would need to somehow only play it while in menus or paused. Any ideas, anyone?
>
I have a cheap HDMI switcher I bought from Maplins, reason being the BT Vision box would complain 
when I plugged something else into one of the TV's other HDMI inputs (!). I don't get where BT can 
decide what I plug into my TV, or why they care, but I digress.

If you order the inputs correctly, then you should never need to use the remote that comes with the 
switcher. The BT box is input 1 and the myth box is 2. I did have another host that I used for Skype 
plugged into input 3. This means that it defaults to 1 except when I switch the myth box on and it 
goes back when I shut the myth box down. Look, no hands!

-- 

Mike Perkins