TV as Monitor, via HDMI

12harry

Well-known Member
Been using this technique for over 1 year and will Render Videos while TV is switched to another HDMI input, to watch TV programmes, via an always-on DVD Recorder/Tuner..
However, I'm noticing that Video Editor will stop - suggesting that "something" has caused a processor crash . . . or any number of other reasons.... definitely NOT every time.... but see below I'm narrowing the Search...


My Q. is this....What signals can TV-HDMI send to the PC?
( Further PSU Tests suggests the TV isn't sending any "Signal" tot he PC - but the PC may be sensitive to some "switching" activity ).
I thought is was 1-way only . . . it transmits Audio and Picture faultlessly.... but I fail to understand how the PC is responding to odd behaviour, when it doesn't if I'm watching the Render-process (or fetching a cup of tea, etc.).

Further thoughts- after some EXPERIMENTS - since just pulling out the Graphics-card HDMI lead appear to create some limited mayhem... the running program can be provoked into Resizing. (( Suggesting a Glitch is doing this, perhaps ))

Also, turning off the TV+Amplifier appears to provoke the PC ( IN PC-HDMI mode )
[ not yet tried switching TV onto a different HDMI channel . . . ]
But the Amplifier alone doesn't appear to affect the PC, so I now focussed on the TV-PSU being the culprit . . . i.e. via the shield on the HDMI lead. I'm wondering if there is a small potential difference present, due to interference suppressors, perhaps . . . and this is enough to make the Processor skip a beat...?

Thoughts?
 
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andy1249

Distinguished Member
TV will have HDMI inputs, amp and PC will have outputs.

The main signal content flow is on the three TMDS channels and is one way from source ( outputs ) to sink ( inputs).

The rest of the connection is for control and handshaking and is two way.
HDMI has a continuous handshaking system that is always checking the status of the line between source and sink and adjusting accordingly.

This is what is causing your issue , when switching to another input while your PC is busy, the handshake will feed back change of status to your PC causing issues.

Your gear does not have a fault.
This is just the way HDMI works and a dedicated PC monitor is your best solution.

By the way, hotplugging, or pulling HDMI cables while units are powered on, can cause more than just temporary mayhem, it can kill your gear, so dont do it.
 
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next010

Distinguished Member
Does your TV have a dedicated PC mode ? (samsungs do for example, rename input label to PC)

It also sounds like the TV is responding to the HDMI-CEC ?, if thats not important you could try turning it off on the TV but doing so will disable CEC control for all HDMI inputs so auto power on, auto input switching etc.

Shot in the dark workarounds
* try using displayport to hdmi cable if PC graphics output has DP output, it may not respond in the same way as the hdmi output

* you can get hdmi splitter 1 input 2 output on amazon for like £10, these clone the hdmi output to 2 displays but they also keep the output active sitting between the TV and PC, as andy1249 points out this may keep the hdmi port active even when you switch inputs on your TV.

There is also the possibility the video encoding/editing crashing is unrelated to HDMI problems. You'd have to go digging in the windows event log to get some clearer answers but thats not for the faint of heart.
 

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