never heard of veon before. from what i can tell they are mid to low end house brand. perhaps because of its limited functionality you're experiencing issues although i still dont understand why, unless you just got a defective one. if possible, testing on a third tv to verify would be nice.
i figured as much with optical. it looks like your tv (or htib) may not support surround sound optical in/out. keep in mind that even if it did pc->tv->htib will always result in stereo sound or at most something like what you have because of how windows recognizes the devices (it sees the tv as a stereo device despite if its actually able to output 5.1 to a htib/avr)
instead of going to tv via optical, why did you not go from devices to tv via optical and from the htib to tv via hdmi? if it works its not really a fix just a bandaid but would be interesting to know in case fixing the issue or returning the tv isnt an option.
i've been thinking ab out it.. and nothing seems to make sense about it.
- its not a problem with lack of hdcp support (copy protection) as this would affect video as well.
- its not a problem where your receiver actually can not accept 5.1 input or provide sound (as it worked before the new tv)
- its not a problem with your pc or xbo outputting 5.1 or audio at all (as it worked before with the old tv in same config)
- its not a limitation of how you're connected via hdmi as you had things connected correctly in the first place and i'm assuming here that you have all the relevant settings correct (as you have been using the htib with xbo/pc/tv for years beforehand)
i'm really starting to reach here... but check (via original connections via hdmi of course)
- mute or speaker on/off buttons
- default audio device in windows
- volume levels
- different receiver audio mode (auto-surround, direct, etc)
- disable audio pass through on receiver (if its an option)
- setting tv/htib settings to defaults
- while tv and htib are on, restarting the device (pc or xbo)
as an experiment.. try connecting from pc->tv via hdmi and via pc->htib via hdmi (two connections). you will need to set your default audio device to the htib. this breaks the hdmi "chain" so that the devices are seen separate not together. do you get audio like normal when doing this method? (note: NOT using hdmi output of htib). this is not a fix, just a test.
honestly i'm thinking it has to be some issue with the tv. not sure what or how but that is what it appears to be at least from my perspective. this is why i would really like to know if when testing with a 3rd tv (preferably non veon) if audio works via hdmi like it should. if it is determined to be the tv, is return or exchange an option?