Structures Reference

This section describes the NetMeeting codec data structures and their uses.

AUDCAP_INFO
AUDCAP_INFO_LIST
VIDCAP_INFO
VIDCAP_INFO_LIST
VIDEO_SIZES

AUDCAP_INFO

typedef struct {
    WORD wFormatTag;
    AUDIO_FORMAT_ID Id;
    char szFormat[ACMFORMATDETAILS_FORMAT_CHARS];
    UINT uMaxBitrate;
    UINT uAvgBitrate;
    WORD wCPUUtilizationEncode;
    WORD wCPUUtilizationDecode;
    BOOL bSendEnabled;
    BOOL bRecvEnabled;
    WORD wSortIndex;
} AUDCAP_INFO;

Use this AUDIO capabilities information structure for both input and output when calling capability APIs. The members are input-only, output-only, or input/output, depending on the API used. Behavior is undefined if these are altered.

wFormatTag: ACM format tag.
Id: (Output-only) Local identification (a.k.a. *Handle*) of this capability entry.
szFormat[ACMFORMATDETAILS_FORMAT_CHARS]: (Output-only) Descriptive string of the format; for example, "Microsoft GSM 6.10".
uMaxBitrate: (Output-only) Worst-case bit rate (maximum rate of data transfer).
uAvgBitrate: Average bit rate for this codec.
wCPUUtilizationEncode: Percent utilization of Pentium 90Mhz needed for compression.
wCPUUtilizationDecode: Percent utilization of Pentium 90Mhz needed for decompression.
bSendEnabled: Okay to use this format for sending.
bRecvEnabled: Okay to use this format for receiving.
wSortIndex: Ordered position of this entry in the capability table. Can be used as input only in IInstallAudioCodecs::ReorderFormats method.

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AUDCAP_INFO_LIST

typedef struct {
    ULONG cFormats;
    AUDCAP_INFO aFormats[VARIABLE_DIM];
} AUDCAP_INFO_LIST;

Use this structure to get a list of AUDCAP_INFO structures.

cFormats: Number of AUDCAP_INFO structures in this list.
aFormats[VARIABLE_DIM]: List of AUDCAP_INFO structures with cFormats number of elements.

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VIDCAP_INFO

typedef struct {
    DWORD dwFormatTag;
    VIDEO_FORMAT_ID Id;
    char szFormat[ACMFORMATDETAILS_FORMAT_CHARS];
    WORD wCPUUtilizationEncode;
    WORD wCPUUtilizationDecode;
    BOOL bSendEnabled;
    BOOL bRecvEnabled;
    WORD wSortIndex;
    VIDEO_SIZES enumVideoSize;
    BITMAPINFOHEADER bih;
    UINT uFrameRate;
    DWORD dwBitsPerSample;
    UINT uAvgBitrate;
    UINT uMaxBitrate;
} VIDCAP_INFO, *PVIDCAP_INFO;

Use this VIDEO capabilities information structure for both input and output when calling capability APIs. The fields are input-only, output-only, or input/output, depending on the API used. Behavior is undefined if these are altered.

dwFormatTag: Format tag of this format.
Id: (Output-only) Local identification (a.k.a. *Handle*) of this capability entry.
szFormat[ACMFORMATDETAILS_FORMAT_CHARS]: (Output-only) Descriptive string of the format; for example, "Microsoft H.263" NetMeeting-specific information.
wCPUUtilizationEncode: Percent utilization of Pentium 90Mhz needed for compression.
wCPUUtilizationDecode: Percent utilization of Pentium 90Mhz needed for decompression.
bSendEnabled: Okay to use this format for sending.
bRecvEnabled: Okay to use this format for receiving.
wSortIndex: (Output-only) Ordered position of this entry in the capability table. This variable can be used as input only in IInstallVideoCodecs::ReorderFormats.
enumVideoSize: Video size for this format. Different video sizes for the same formats must be added as separate formats.
bih: BITMAPINFOHEADER structure for the video size in enumVideoSize.
uFrameRate: Number of frames per second displayed by this codec.
dwBitsPerSample: Number of bits per sample for this format. Must match the value in bih.biBitCount in the BITMAPINFOHEADER structure.
uAvgBitrate: Average bit rate for this codec.
uMaxBitrate: (Output-only) Worst-case bit rate (maximum rate of data transfer).

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VIDCAP_INFO_LIST

typedef struct {
    ULONG cFormats;
    VIDCAP_INFO aFormats[VARIABLE_DIM];
} VIDCAP_INFO_LIST;

Use this structure to get a list of VIDCAP_INFO structures.

cFormats: Number of VIDCAP_INFO structures in this list.
aFormats[VARIABLE_DIM]: List of VIDCAP_INFO structures, with cFormats number of elements.

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VIDEO_SIZES

enum VIDEO_SIZES {
    Small,
    Medium,
    Large
};

Use this structure for the enumeration values for the three video sizes supported by NetMeeting.

Small: Small-size video.
Medium: Medium-size video.
Large: Large-size video.

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