Currently Splashtop CamCam only supports audio sample rates between 32K and 48K HZ.
Some cameras with built-in microphones only support the 16K HZ audio sample rate. For these cameras, CamCam will still display video, but no audio, and will display a notification message about this on the computer side.
Note that you can try to configure a camera with a built-in microphone to adjust the audio sample rate, if it supports higher sample rate values.
The sequence/option names may vary according to your system, but basically you need to open the Control Panel, click Sound, click the Recording tab, select the camera's built-in microphone device, click Properties, click the Advanced tab in the Microphone Properties dialog box, and then select the correct audio sample rate from the list. Please see the attached illustration for an example.