Problem displaying Sky Q HDR HLG formats with Arcam AV850 without screen locking out showing Invalid format


Standard Member
Similar issue with Sky Q > Onkyo Tx-l50 > Philips 50PUS9005/12
Sky Q set to 2160 10 bit, able to pass UHD, HDR etc, but when “coming off” a UHD/HDR source on the sky box, I get an “Invalid video format” on the tv, even though picture and sound are displayed fine.
Reselecting the same input source hdmi with the tv remote clears the warning.
Have tested Sky Q > TV > onkyo via ARC instead, no error messages, but av sync issues that tipped the boss of the house over the edge so had to revert.
Swapped HDMI cables, no better. It’s definitely a HLG handshaking thing via the AVR.

Geordie Amanda

Standard Member
I ended up buying a Denon x4700H as my Onyko tx zr800 would not pass though HLG from SKY Q. The only work around was to plug directly into the tv (a 5 year old LG OLED) from the SKY Q, but that caused handshake issues-not created by the HDMI cable btw. The only work around I had available for ease of watching 4k on SKY at the time, was to simply not watch the HLG version of SKYs 4k shows, as luckily they offer both flavours, or at least always 4K and sometimes the addition of HLG. Funny thing was HLG from the BBC, using the tvs internal iplayer app, allowed 4K HLG.


Standard Member
it is definitely a handshake issue if you read my question below
After further investigation I purchased Antiference Premium certified cables to test if HDMI leads were the problem. Changing cables made the problem worse more invalid format errors. Also tried setting up ARC channel but unable to obtain Dolby Digital + Audio signal only Dolby Digital.
Cannot understand why Netflix on Apple TV will play 4K 2K HDR10 (Dolby Atmos) but when same AV850 Sat Input and HDMI leads are used from Sky Q box showing 4K 2K HD10 screen locks up with Invalid Format Signal.
Sky HLD HDR channels requires 1 or 2 input toggles via AV850 to display ok.
Netflix Via Sky channels requires 1 to 6 input toggles via AV850 to display ok.
Test programs used Sky Q Gang of Lemurs & The Crown Netflix.
From all the testing I think it is looking more like the fault of the Sky Q box version 32B206 and implication of its HDMI output.
After exhausting all possible solutions:
I returned my Arcam AV850 to Arcam who replaced the HDMI Card and fixed a faulty display.
During the period the amp was in for repair I was loaned a new Arcam AVR30 which played all HLD and Netflix programs without problem.
My repaired Arcam AV850 still has the same problem but not so frequent.
The difference in handshake is with AV amps using HDMI 2.0a causing intermittent connection on entering or leaving HLG Content (only option is to toggle input from sky to another source and back again)
To overcome the problem you will need a device which is HDMI 2.0b compatible to match the Sky Q box version 32B206.
Searching the Internet found the following info see below
The difference between HLG and HDMI 2.0b
HDMI 2.0b is basically a carryover from HDMI 2.0a with small refinements that add support for HDR, notably HLG, which is just a different way to transmit HDR content.
Armed with this new information, we expect you to now be able to make the best decision for connecting to any device you wish.

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