I have what should be a simple problem but haven't been able to find a
solution.
I am using DirectX 9 to play a simple 16 bit mono sound file in a Sound card
modem application. The playback code is simple:
devSelectedPlaybackDevice.SetCooperativeLevel(Me.Handle,
CooperativeLevel.Priority)
bufPlayback = New SecondaryBuffer(Filename,
devSelectedPlaybackDevice)
bufPlayback.Volume = -5000 + 50 * intOutputLevel ' -5000=off,
0=full volume
bufPlayback.Play(0, BufferPlayFlags.Default)

All this works fine IF the application window is the active window. If the
application
Window is not the active window the sound card capture code (not shown)
continues to work fine but there is no playback from the sound card output.
This works the same way on several different sound cards (internal or
external USB). There is no exception thrown just no output from the sound
card. Once the window containing the application is made active again it
plays correctly.

On Thu, 18 Sep 2008 09:05:01 -0700, Rick Muething wrote:

Add GlobalFocus to your BufferDescription.Flags.

Chris,
That sounds like it should do the trick. But I am having problems with the
exact syntax and commands to set the GlobalFocus flag for the buffer.
Can you prompt me with the sequence of actual commads to set the buffer
flags and create the buffer with the global focus?

Thanks

--
Rick Muething
Winlink Development Team

"Chris P." wrote:

On Thu, 18 Sep 2008 10:21:01 -0700, Rick Muething wrote:

I haven't used the managed interfaces but it looks like you want the other
constructor that allows you to pass the BufferDescription as the second
parameter. There may be a problem however if the BufferDescription.Format
you create doesn't match the WaveFormat from the file, that part will have
to be tested.

wFormat = new WaveFormat()
wFormat.AverageBytesPerSecond = 'read these values from file
wFormat.BitsPerSample =
wFormat.BlockAlign =
wFormat.Channels =
wFormat.FormatTag = WaveFormatTag.Pcm
wFormat.SamplesPerSecond =

BuffDesc = new BufferDesc(wFormat)

devSelectedPlaybackDevice.SetCooperativeLevel(Me.Handle, CooperativeLevel.Priority)