Audio return channel
On 25/06/17 17:44, Richard Tobin wrote:
In article ,
Jeff Layman wrote:
I have a Panasonic TX-55CX680B TV and Onkyo AV TX-SR252 receiver
connected via HDMI.
I also have a Panasonic TV with an Onkyo receiver using ARC.
It behaves the same way as yours.
However, if I use the TV's remote control to change the TV's volume with
the AV receiver on, the TV displays "Home cinema volume" with an arrow
pointing towards + or - (depending on whether I am increasing or
decreasing the volume), but no number appears on the TV screen to
indicate what the volume level is. Strangely, though, the AV receiver
display also changes and displays a number which changes with the volume
The HDMI protocol does provide a operation System Audio Mode Status
for the receiver to report its current volume to the TV, but
apparently either the Panasonic TV doesn't request or use it or the
Onkyo doesn't send it.
My TV also doesn't display anything indicating when the receiver is
muted, which is also reported in the same HDMI operation.
Any idea if the "Home cinema volume" OSD wording which appears when ARC
is operating is generated by the TV when it senses ARC or is it
generated by the AV receiver? There is no mention of this wording in the
Onkyo manual or Panasonic manual, although the latter somewhat
ambiguously states "The displayed item may vary depending on the
I don't see anything in the HDMI spec allowing the receiver to
specify a message for use by the TV.
"Home Cinema" is the term used in the Panasonic manual. It appears
in the index and in the "Viera Link" Speaker control section it points
to, and the speaker selection menu (also shown in that section of the
manual) has a choice of "TV" and "Home Cinema".
Thanks for the reply.
I had seen the info in the "Viera Link" section of the manual. I wonder
if there is something specific to Panasonic Home Cinema Systems (they
don't seem to do AVRs like the Onkyo) using Viera Link which would allow
a Panasonic TV to display the volume level as a figure when used with a
Panasonic HCS. It would have to be additional to the HDMI spec, but I
see no reason why it couldn't be done if Panasonic decided to do it. It
just seems strange that the Panasonic TV and Onkyo AVR can display the
volume level as number individually, but don't when connected to each
other. I wonder if Denon, Yamaha, etc AVRs behave the same way.