KSAUDIO_MIXCAP_TABLE structure (ksmedia.h)
The KSAUDIO_MIXCAP_TABLE structure specifies the mixing capabilities of a supermixer node (KSNODETYPE_SUPERMIX). This structure is used to get or set the data value for the KSPROPERTY_AUDIO_MIX_LEVEL_CAPS property.
Syntax
typedef struct {
ULONG InputChannels;
ULONG OutputChannels;
KSAUDIO_MIX_CAPS Capabilities[1];
} KSAUDIO_MIXCAP_TABLE, *PKSAUDIO_MIXCAP_TABLE;
Members
InputChannels
Specifies the number of input channels.
OutputChannels
Specifies the number of output channels.
Capabilities[1]
Contains the first entry in a two-dimensional array of KSAUDIO_MIX_CAPS structures. Given a supermixer node with m input channels and n output channels, the array contains m* elements. Each element describes the mix-level capabilities of the path from a particular input channel to a particular output channel.
Remarks
The Capabilities table is stored as a two-dimensional array:
KSAUDIO_MIX_CAPS Capabilities[M*N];
The table is an M-by-N matrix that maps M input channels into N output channels. The following table shows the mapping of Capabilities array elements to the supermixer node's M*N input-output paths.
| Array element | Input-output path |
|---|---|
| Capabilities[0] | Input channel 0 to output channel 0 |
| Capabilities[1] | Input channel 0 to output channel 1 |
| Capabilities[N-1] | Input channel 0 to output channel N-1 |
| Capabilities[N] | Input channel 1 to output channel 0 |
| Capabilities[N+1] | Input channel 1 to output channel 1 |
| Capabilities[2N-1] | Input channel 1 to output channel N-1 |
| Capabilities[M*N-1] | Input channel M-1 to output channel N-1 |
In other words, the mixer caps for the path from input channel i to output channel j are contained in Capabilities[i * N + j]. If no path exists from input i to output j, set the Mute member of matrix element (i,j) to TRUE.
The size of the table is calculated from the KSAUDIO_MIXCAP_TABLE structure that is retrieved by a KSPROPERTY_AUDIO_MIX_LEVEL_CAPS get property request. If the structure's InputChannels and OutputChannels members have the values m and n, the total storage required for the KSAUDIO_MIXCAP_TABLE structure plus the KSAUDIO_MIX_CAPS array is calculated as
sizeof(KSAUDIO_MIXCAP_TABLE) + (mn - 1)sizeof(KSAUDIO_MIX_CAPS)
If the client sends an initial KSPROPERTY_AUDIO_MIX_LEVEL_CAPS request in which the property size is specified as 2*sizeof(ULONG), the miniport driver should fill in only the first two members of the KSAUDIO_MIXCAP_TABLE structure, InputChannels and OutputChannels. The client can then send a second property request with enough storage allocated to contain the capabilities of all the channels.
Requirements
| Requirement | Value |
|---|---|
| Header | ksmedia.h (include Ksmedia.h) |