OBS Studio - How to enable the "Video Capture Device" as a source USBHDCAP

Open the "video capture device" Source, properties.

1. Change [Audio Output Mode] from these:

Output desktop audio (DirectSound)

Output desktop audio(WaveOut)

2. Change [Audio Output Mode] to this:

 Capture audio only

This is not what it seems, selecting one of the others pipes the output of the device through a mix with the other source; either "Desktop audio" DirectSound or WaveOut .. which I suspect are Desktop1 Desktop2

If you select one of those then you disable the ability to enumerate and use the "Video Capture Device" as an audio source in the "mixer" panel of OBS.

Instead "Capture audio only" means, do not pre-process it and mix with anything else, pipe it straight into OBS as an independent source. It literally means "leave it alone" do not "do anything to it" simply "present it".

You CAN still check the box [x] User custom audio device, and "must" use CY3014USB, Analog 01 WaveIn to connect the video capture device to the OBS mixer.

This "might" seem like it would disable the ability to capture [both] video and audio to a [Start Recording] session. It DOES NOT ! 

Any Streaming or Recording includes [both] video and audio.

This is a very BIG deal.. it explains the original interpretive conceit with OBS and why its so hard to use for most people.

OBS Studio - Monitor silent with Startech USBHDCAP device "fix"

Here is how to fix a video capture device that records video and audio, but does not play sound while recording.

1. Click > [Settings] in Controls Panel (Lower right)

2. Click "Advanced" in Left Ribbon panel

3. Click [Audio] > Audio Monitoring Device [drop down]

Select a device other than "Bluetooth Headphones (2- Bluetooth Audio)" 

Example:

Select "Bluetooth Headset (2- Bluetooth Audio)"

4. Click [Apply] in lower right corner

5. Click [OK] in lower right corner

The A2DP Profile for some reason on OBS 21.1.2 (64 Bit) does not down sample the 48 Khz Line Input for the CVBS Composite or S-Video Inputs properly. When it defaults to "Default" or "Bluetooth Headphones (2- Bluetooth Audio)" the Monitoring audio cuts out and goes silent. Also the "Default" takes out not only the OBS video capture source, but any other Audio source on the Desktop, including Browsers playing video or other Application sources.

I suspect the source code for OBS 21.1.2 may not be initializing the windows mixer properly or not handling down sampling properly.. or the A2DP profile is just not working properly.

In any event the change is immediate and does not require restarting the application and all other audio sources are mixed and can be heard. Although with this video capture device, the video device audio input is not selectable and it captures the Desktop mix instead

Also a "Custom" audio device that selects the CY3014 device must be used or there will be no audio capture or monitoring.