Dear all,
i have a vero 4k (latest version with Kodi 19.1) attached to my AV-Receiver and from there video and audio goes further to my projector.
When i use the AV Receiver for sound, i can control it with the vero 4k remote +/- buttons… But usually for “daily life” usage, the AV Receiver is off and i use the in-built sound of my projector (ultra short distance projector with integrated soundbar).
I want to change the volume of the projector with the vero 4k remote. How can I do it?
Thank you 
Most likely the projector doesn’t allow volume change via CEC so you can not do it unless you use IR Sender to mimic your projector remote.
I think it may be a limitation of CEC. From what I understand there is only one amplifier type device id on the bus and the AVR is taking that role. When the AVR is off it is going into passthrough mode but it is still registered on the CEC bus as the amplifier device. As such I don’t think under the current CEC standards it is possible for the AVR to forward the volume commands to a secondary amplifier device. Additionally Kodi will only send CEC volume commands directed to the amplifier id. From what I remember reading on the subject (Kodi forum? Kodi wiki? don’t really remember where) when the programmers were working on this they found that few TV’s would actually respond to sending volume commands to the display device so they didn’t allow for that option to be used. As such any input device that is relying on Kodi to control volume (any device running Kodi on top of any operating system) can only do so via CEC to an amplifier device (AVR or soundbar) or by adjusting internal volume (which only takes effect if either there is no amplifier or CEC is disabled in Kodi). The latter option additionally only works with PCM output as it doesn’t manipulate passthrough audio.