IAMExtTransport::GetTransportBasicParameters method (strmif.h)

Article
07/27/2023

[The feature associated with this page, DirectShow, is a legacy feature. It has been superseded by MediaPlayer, IMFMediaEngine, and Audio/Video Capture in Media Foundation. Those features have been optimized for Windows 10 and Windows 11. Microsoft strongly recommends that new code use MediaPlayer, IMFMediaEngine and Audio/Video Capture in Media Foundation instead of DirectShow, when possible. Microsoft suggests that existing code that uses the legacy APIs be rewritten to use the new APIs if possible.]

The GetTransportBasicParameters method retrieves general properties of the external transport.

Syntax

HRESULT GetTransportBasicParameters(
  [in]      long     Param,
  [in, out] long     *pValue,
  [in, out] LPOLESTR *ppszData
);

Parameters

[in] Param

Specifies which property to receive.

[in, out] pValue

Pointer to a variable that receives a long integer value. See Remarks for more information.

[in, out] ppszData

Pointer to a variable of type LPOLESTR that receives a string. See Remarks for more information.

Return value

When this method succeeds, it returns S_OK. Otherwise it returns an HRESULT error code.

Remarks

The Param parameter is a flag that specifies which property to retrieve. Some properties are numeric; these are returned in the pValue parameter. Other properties are string values; these are returned in the ppszData parameter. For a list of flags and expected values, see IAMExtTransport::SetTransportBasicParameters.

If the method returns a string, the caller must free the string, using the CoTaskMemFree function.

DV and MPEG Camcorder Implementation

MSDV supports the following additional flags:

ED_RAW_EXT_DEV_CMD: Invokes a raw AV/C command. Specify the AV/C command as an array of bytes in the ppszData parameter. Specify the size of the command, in bytes, in the pValue parameter. When the method returns, ppszData contains the response from the device, and pValue contains the size of the response, in bytes. The AV/C command is passed directly to the device with no validation or error checking.
The response payload might be larger than the command. It is the caller's responsibility to allocate enough space in the buffer for the response. The maximum payload size is 512 bytes.

For more information, see Issuing Raw AV/C Commands.

ED_TRANSBASIC_INPUT_SIGNAL: Retrieves the signal format that the DV camcorder is designed to accept. Returns one of the following constants in pValue.

Constant	Description
ED_TRANSBASIC_SIGNAL_525_60_SD	NTSC SD signal.
ED_TRANSBASIC_SIGNAL_525_60_SDL	NTSC SDL (long-play) signal.
ED_TRANSBASIC_SIGNAL_625_50_SD	PAL SD signal.
ED_TRANSBASIC_SIGNAL_625_50_SDL	PAL SDL (long-play) signal.
ED_TRANSBASIC_SIGNAL_MPEG2TS	D-VHS signal.

ED_TRANSBASIC_OUTPUT_SIGNAL: Retrieves the signal format that the DV camcorder is designed to transmit. Returns one of the constants listed for the ED_TRANSBASIC_INPUT_SIGNAL flag.

MSTape supports additional values for ED_TRANSBASIC_INPUT_SIGNAL and ED_TRANSBASIC_OUTPUT_SIGNAL.

Constant	Description
ED_TRANSBASIC_SIGNAL_2500_60_MPEG	25-Mbps/60 MPEG stream.
ED_TRANSBASIC_SIGNAL_1250_60_MPEG	12.5-Mbps/60 MPEG stream.
ED_TRANSBASIC_SIGNAL_0625_60_MPEG	6.25-Mbps/60 MPEG stream.
ED_TRANSBASIC_SIGNAL_2500_50_MPEG	25-Mbps/50 MPEG stream.
ED_TRANSBASIC_SIGNAL_1250_50_MPEG	12.5-Mbps/50 MPEG stream.
ED_TRANSBASIC_SIGNAL_0625_50_MPEG	6.25-Mbps/50 MPEG stream.
ED_TRANSBASIC_SIGNAL_UNKNOWN	Unknown signal format.

These flags are defined in the header file Xprtdefs.h.

In Windows XP Service Pack 2 and later, the following additional signal types are defined for the ED_TRANSBASIC_INPUT_SIGNAL and ED_TRANSBASIC_OUTPUT_SIGNAL flags.

Constant	Description
ED_TRANSBASIC_SIGNAL_525_60_DV25	DVCPRO 25, 525-60.
ED_TRANSBASIC_SIGNAL_625_50_DV25	DVCPRO 25, 625-50.
ED_TRANSBASIC_SIGNAL_525_60_DV50	DVCPRO 50, 525-60.
ED_TRANSBASIC_SIGNAL_625_50_DV50	DVCPRO 50, 625-50.
ED_TRANSBASIC_SIGNAL_HD_60_DVH1	DVCPRO 100, 1080i or 720p
ED_TRANSBASIC_SIGNAL_HD_50_DVH1	DVCPRO 100, 1080i only

To use these constants, include the header file Xprtdefs.h from the Windows SDK.

Requirements

Requirement	Value
Minimum supported client	Windows 2000 Professional [desktop apps only]
Minimum supported server	Windows 2000 Server [desktop apps only]
Target Platform	Windows
Header	strmif.h (include Dshow.h)
Library	Strmiids.lib

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