Monitor HDMI switching shuts off record? at DVinfo.net

Derek Reich · December 14th, 2011, 07:09 PM

Does anyone know if there is a menu setting which would disable my 7D from interrupting a record session because the HDMI input on a monitor was switched to another input? I'm using the 7D with another camera (Sony EX) and have both going into a monitor which has both HDMI and component inputs. If I switch the input from HDMI (the 7D) to component (the EX) no problem. But if I switch back to HDMI, the 7D stops recording.
Is there any way to avert this? I'd like to be able to switch back and forth without having to restart the recording every time. Before anyone asks, there is nothing in the monitor menu so there's no hope there.

Jon Fairhurst · December 14th, 2011, 08:03 PM

My guess is that there is no easy workaround. The monitor is likely sending new metadata, and the 7D sees this as connecting to a new monitor. That probably generates a hardware interrupt in the software. When that happens, the camera assumes that there was a major change, so all bets are off and the recording stops.

You *might* be able to get around this if you insert an active HDMI distribution amp. That said, I believe that the DA will still send the new metadata, and the recording will still stop.

Derek Reich · December 15th, 2011, 08:27 AM

thanks, Jon
I wondered if that wasn't what was going on.... looks like a dedicated monitor for each camera is going to be the solution.

Gerry Gallegos · December 16th, 2011, 08:54 AM

When you switch sources on monitor from one input to another the HDCP (Copy protection) key is released which causes the 7D to switch modes, which in turn stops the recording.
HDCP is a part of the HDMI format and cannot usually be bypassed so the 1 monitor per cam is your only solution, unless you have a device that stores the HDCP key and does the switching for you (expensive).

HDCP is making the whole world of commercial AV a nightmare these days.

Hope this answers your question.

GG

Jon Fairhurst · December 16th, 2011, 11:13 AM

I don't know that DSLRs implement HDCP. There are additional licensing costs to do that, and the camera has no need to implement copy protection.

My guess is that it has to do with the handshake between source and sink as required by CEA-861 for implementing the EDID information. The two devices have to negotiate to determine what resolution and bit depth will be delivered. When the 7D connects to what it sees as a new sink device, it could assume that it needs to change the output format. At that point, it's "game over."

CEA: CEA Standards - Standards Listings by Committee

December 14th, 2011, 07:09 PM	#1
Derek Reich Major Player Join Date: Dec 2008 Location: Washoe Valley, NV Posts: 304	Monitor HDMI switching shuts off record? Does anyone know if there is a menu setting which would disable my 7D from interrupting a record session because the HDMI input on a monitor was switched to another input? I'm using the 7D with another camera (Sony EX) and have both going into a monitor which has both HDMI and component inputs. If I switch the input from HDMI (the 7D) to component (the EX) no problem. But if I switch back to HDMI, the 7D stops recording. Is there any way to avert this? I'd like to be able to switch back and forth without having to restart the recording every time. Before anyone asks, there is nothing in the monitor menu so there's no hope there. __________________ www.zooprax.com

December 14th, 2011, 08:03 PM	#2
Jon Fairhurst Inner Circle Join Date: May 2006 Location: Camas, WA, USA Posts: 5,513	Re: Monitor HDMI switching shuts off record? My guess is that there is no easy workaround. The monitor is likely sending new metadata, and the 7D sees this as connecting to a new monitor. That probably generates a hardware interrupt in the software. When that happens, the camera assumes that there was a major change, so all bets are off and the recording stops. You might be able to get around this if you insert an active HDMI distribution amp. That said, I believe that the DA will still send the new metadata, and the recording will still stop. __________________ Jon Fairhurst

December 15th, 2011, 08:27 AM	#3
Derek Reich Major Player Join Date: Dec 2008 Location: Washoe Valley, NV Posts: 304	Re: Monitor HDMI switching shuts off record? thanks, Jon I wondered if that wasn't what was going on.... looks like a dedicated monitor for each camera is going to be the solution. __________________ www.zooprax.com

December 16th, 2011, 08:54 AM	#4
Gerry Gallegos Major Player Join Date: Oct 2007 Location: Houston, Texas Posts: 262	Re: Monitor HDMI switching shuts off record? When you switch sources on monitor from one input to another the HDCP (Copy protection) key is released which causes the 7D to switch modes, which in turn stops the recording. HDCP is a part of the HDMI format and cannot usually be bypassed so the 1 monitor per cam is your only solution, unless you have a device that stores the HDCP key and does the switching for you (expensive). HDCP is making the whole world of commercial AV a nightmare these days. Hope this answers your question. GG

December 16th, 2011, 11:13 AM	#5
Jon Fairhurst Inner Circle Join Date: May 2006 Location: Camas, WA, USA Posts: 5,513	Re: Monitor HDMI switching shuts off record? I don't know that DSLRs implement HDCP. There are additional licensing costs to do that, and the camera has no need to implement copy protection. My guess is that it has to do with the handshake between source and sink as required by CEA-861 for implementing the EDID information. The two devices have to negotiate to determine what resolution and bit depth will be delivered. When the 7D connects to what it sees as a new sink device, it could assume that it needs to change the output format. At that point, it's "game over." CEA: CEA Standards - Standards Listings by Committee __________________ Jon Fairhurst