dshow: alert as to ramifications of switching crossbar routing

Signed-off-by: rogerdpack <rogerpack2005@gmail.com>

doc/indevs.texi

@@ -229,19 +229,26 @@ Select audio capture pin to use by name or alternative name.
 @item crossbar_video_input_pin_number
 Select video input pin number for crossbar device. This will be
 routed to the crossbar device's Video Decoder output pin.
+Note that changing this value can affect future invocations
+(sets a new default) until system reboot occurs.
 
 @item crossbar_audio_input_pin_number
 Select audio input pin number for crossbar device. This will be
 routed to the crossbar device's Audio Decoder output pin.
+Note that changing this value can affect future invocations
+(sets a new default) until system reboot occurs.
 
 @item show_video_device_dialog
 If set to @option{true}, before capture starts, popup a display dialog
 to the end user, allowing them to change video filter properties
 and configurations manually.
-Note that for crossbar devices, this may be needed at times to toggle
-between PAL and NTSC input frame rates and sizes, etc.  Possibly
-enabling different scan rates/frame rates and avoiding green bars at
-the bottom, etc.
+Note that for crossbar devices, adjusting values in this dialog
+may be needed at times to toggle between PAL (25 fps) and NTSC (29.97)
+input frame rates, sizes, interlacing, etc.  Changing these values can
+enable different scan rates/frame rates and avoiding green bars at
+the bottom, flickering scan lines, etc.
+Note that with some devices, changing these properties can also affect future
+invocations (sets new defaults) until system reboot occurs.
 
 @item show_audio_device_dialog
 If set to @option{true}, before capture starts, popup a display dialog