Manually Downloading Bands

[C++]

You can manually download a band in one of the following ways:

Obtain an IDirectMusicBand interface from a loaded object, and call the IDirectMusicBand::Download method. (See the following example.) This is the best way to download the band if you want to unload it after any segments using the band have been released.
Call the IDirectMusicSegment::SetParam method with the GUID_Download parameter to download the band in the segment's first band track. You can also use IDirectMusicPerformance::SetParam to set this parameter on the primary segment, or IDirectMusicTrack::SetParam to set it directly on a band track. See Setting and Retrieving Track Parameters.

There is no danger in downloading the same instrument multiple times. If an instrument appears in one band multiple times or if it appears in multiple bands that are all opened and downloaded at the same time, only one copy of the instrument is sent down to the synthesizer.

The following function loads a band from disk and downloads it:

HRESULT myDownloadBand(
    IDirectMusicLoader *pILoader,      // Loader interface
    IDirectMusicBand **ppBand,         // To retrieve pointer
    IDirectMusicPerformance *pPerf,    // Performance to use band
    WCHAR *pwszFile)                   // File to load
 
{
    HRESULT hr;
    DMUS_OBJECTDESC Desc;              // Descriptor
 
    // Start by initializing Desc with the file name and GUID
    // for the band object.
 
    wcscpy(Desc.wszFileName,pwszFile);
    Desc.dwSize = sizeof(Desc);
    Desc.guidClass = CLSID_DirectMusicBand; 
    Desc.dwValidData = DMUS_OBJ_CLASS | 
            DMUS_OBJ_FILENAME | DMUS_OBJ_FULLPATH;
 
    hr = pILoader->GetObject(&Desc, IID_IDirectMusicBand,
            (void **) ppBand);
    if (SUCCEEDED(hr))
    {
 
        // Download the band via the performance.
        hr = (*ppBand)->Download(pPerf);
 
    }
    return hr;
}