Not really a developer here, just a guy with an idea… and just enough semi-knowledge to be dangerous.
The Bravia ST smartapp works well to control a Bravia smart TV’s basic functionality.
The functions in that app are available to webcore.
It is possible to pass variables to webcore via endpoint.
It is possible to have Alexa hear numbers and translate those to variables.
So it would be possible to write an Alexa skill that hears you say “alexa, channel two fifteen”,
And that skill would send a string including 2 1 and 5, in that order, to a piston’s endpoint.
The endpoint for a piston can receive those and, based on it, send 2 1 5 to the Bravia.
Which then changes the channel on your cable box to 215 via the IR blaster included with the tv.
I’m imagining this because it’s now been three months since Sony released Alexa control of the 2017 sets and a handful of 2016 units… and they have done nothing since. And when you ask them about it, they say they have no ETA for any other sets. So who knows whether they will ever get around to your set or mine??
Anyway, we currently have the means to do it without Sony. I tested channel change and input change pistons, and they work well.
I’ll have to start exploring Alexa skill writing… along with passing variables to webcore.