AV-1081DG and H.254 Issue

Good Morning,

We have a couple of one button studios set up this way:

Mac OSX mini
Canon Vixia HF G20
Microphone running into an audio mixer
Audio out of the mixer into the camera
HDMI out of the camera to Blackmagic H.254
From Blackmagic to Mac via USB 2.0

In this setup, audio is heard on the recorded videos with the Canon cameras. We have had a problem with these types of cameras failing on the HDMI out so we attempted to use a PTZ in its place for easier focusing and movement of the camera in the studio. However, when this camera is used (AV-1081DG) there is no audio on the recording. When testing the PTZ camera with the Blackmagic Media Express, we can see immediately that there is no audio being sent from the Blackmagic box to the computer. If we use the Canon camera it does. As a test, we remove the HDMI from the Blackmagic box and plug it directly into a TV which then audio from the microphone can be heard. What could possibly be causing the audio not either not be accepted by the Blackmagic box or be allowed to pass to the computer?

Thanks,
Scott

Is there any situation to where this device will not send the audio from an HDMI cable through the USB 2.0 to the computer?