Re: Audio on preview stream

"Chris P. [MVP]" <msdn@xxxxxxxxxxxx> wrote in

If the capture device relays the audio through the sound card via an
external cable then it is more complicated. First you must set the
crossbar on the capture device so that the audio output of the capture
device is connected to the correct input (tuner, line-in etc), this
can also be set to follow the video. Second you add the source filter
for the sound card, get it's mixer interface from the pins and make
sure it's configured for the correct source (line-in usually).
Finally you can render its output pin. The order of these events
actually doesn't matter just presented in logical order here.

Aha, we're on to something here. When I select the Audio Decoder Out and
choose the 'line in' in graphedt I get audio with both my test devices.
Now, on one device the Audio Decoder Out is a pin on the Video crossbar and
the second device has a separate audio crossbar. Is there a consistent way
of programmatically finding the 'Audio Decoder Out' pin for a given device?