IAMExtTransport::GetCapability 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 It has been superseded by MediaPlayer, IMFMediaEngine, and Audio/Video Capture in Media Foundation.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 GetCapability method retrieves the general capabilities of the transport.

Syntax

HRESULT GetCapability(
  [in]  long   Capability,
  [out] long   *pValue,
  [out] double *pdblValue
);

Parameters

[in] Capability

Specifies the capability to check. See Remarks for more information.

[out] pValue

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

[out] pdblValue

Pointer to a variable that receives a double. See Remarks for more information.

Return value

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

Remarks

The Capability parameter is a flag that specifies which capability to check. The method returns the result either in the pValue parameter or in the pdblValue parameter, depending on the capability flag.

For the following flags, the method returns the value OATRUE or OAFALSE in the pValue parameter. The value OATRUE indicates that the capability is present, while the value OAFALSE indicates it is absent.

Capability Flag	Description
ED_TRANSCAP_CAN_ASSEMBLE	Transport can use assemble record mode (record new tracks that link seamlessly to the control track from the previously recorded segment).
ED_TRANSCAP_CAN_BUMP_PLAY	Transport can synchronize by varying speed.
ED_TRANSCAP_CAN_DELAY_AUDIO_IN	Transport can perform delayed-in audio edits.
ED_TRANSCAP_CAN_DELAY_AUDIO_OUT	Transport can perform delayed-out audio edits.
ED_TRANSCAP_CAN_DELAY_VIDEO_IN	Transport can perform delayed-in video edits.
ED_TRANSCAP_CAN_DELAY_VIDEO_OUT	Transport can perform delayed-out video edits.
ED_TRANSCAP_CAN_DETECT_LENGTH	Transport can detect the length of the media.
ED_TRANSCAP_CAN_EJECT	Transport can eject the media.
ED_TRANSCAP_CAN_FREEZE	Transport can freeze/pause.
ED_TRANSCAP_CAN_INSERT	Transport can use insert record mode (record individual tracks while locked to a prerecorded control track).
ED_TRANSCAP_CAN_PLAY_BACKWARDS	Transport can play backward.
ED_TRANSCAP_CAN_SET_EE	Transport can show the device's input on its output.
ED_TRANSCAP_CAN_SET_PB	Transport can show media playback on its output.
ED_TRANSCAP_FIELD_STEP	Transport responds to a frame advance command by advancing one field.
ED_TRANSCAP_HAS_CLOCK	Device has a clock.
ED_TRANSCAP_HAS_DT	Device has dynamic tracking.
ED_TRANSCAP_HAS_TIMER	Device has a timer.
ED_TRANSCAP_HAS_TUNER	Device has a tuner.
ED_TRANSCAP_IS_MASTER	Device is the master clock for synchronizing.
ED_TRANSCAP_MULTIPLE_EDITS	Device supports multiple edit events.
ED_TRANSCAP_NEEDS_CUEING	Device must be cued before it performs an edit.
ED_TRANSCAP_NEEDS_TBC	Device needs to be calibrated.

For the following flags, the method returns a numeric value in the pValue parameter.

Capability Flag	Returned Value
ED_TRANSCAP_LTC_TRACK	Returns the track number of the LTC timecode track, or ED_ALL if there is no dedicated timecode track.
ED_TRANSCAP_NUM_AUDIO_TRACKS	Returns the number of audio tracks.

For the following flags, the method returns a value in the pdblValue parameter.

Capability Flag	Returned Value
ED_TRANSCAP_FWD_SHUTTLE_MAX	Maximum forward speed in shuttle mode, as a multiple of play speed.
ED_TRANSCAP_FWD_SHUTTLE_MIN	Minimum forward speed in shuttle mode, as a multiple of play speed.
ED_TRANSCAP_FWD_VARIABLE_MAX	Maximum forward speed, as a multiple of play speed.
ED_TRANSCAP_FWD_VARIABLE_MIN	Minimum forward speed, as a multiple of play speed.
ED_TRANSCAP_REV_SHUTTLE_MAX	Maximum reverse speed in shuttle mode, as a multiple of play speed.
ED_TRANSCAP_REV_SHUTTLE_MIN	Minimum reverse speed in shuttle mode, as a multiple of play speed.
ED_TRANSCAP_REV_VARIABLE_MAX	Maximum reverse speed, as a multiple of play speed.
ED_TRANSCAP_REV_VARIABLE_MIN	Minimum reverse speed, as a multiple of play speed.

DV Implementation

MSDV does not support this method. It returns E_NOTIMPL.

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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