Capture, Preview, and Still Category

The following GUIDs correspond to categories that capture video streams, preview video streams, and capture still images (if supported by the hardware):

  • PINNAME_VIDEO_CAPTURE

    Capture category output pins provide a stream of compressed or uncompressed digital video. This stream category is used to write movies to disk, to video conference, and for image analysis.

  • PINNAME_VIDEO_PREVIEW

    Preview category output pins provide a stream of uncompressed digital video. This stream category is used to view the video stream on the local monitor, in either RGB or YUV formats that can be directly displayed by DirectDraw. In resource-limited situations, capture minidrivers should prioritize preview stream pins lower than capture stream pins.

  • PINNAME_VIDEO_STILL

    Still category output pins are used with dual-mode cameras that are capable of producing both a capture stream and a still image stream (that is often of higher quality than the capture stream). The still image stream includes the ability to externally or programmatically trigger acquisition of an image.

The capture, preview, and still stream pin categories are almost identical in terms of data formats and stream characteristics.

Note  : Because many cameras produce only a single output stream, Microsoft DirectShow includes a Smart Tee filter that splits a single stream into a Capture and a Preview stream. Therefore, minidrivers for cameras that produce only a single stream should not internally duplicate their data streams to produce a preview stream.

When specifying PINNAME_VIDEO_CAPTURE, or PINNAME_VIDEO_PREVIEW, or PINNAME_VIDEO_STILL pins, use the information listed in the following table.

Attribute Value

DataRange Structure

KS_DATARANGE_VIDEO (frames only)

KS_DATARANGE_VIDEO2 (fields or frames, bob or weave settings)

KS_DATARANGE_MPEG1_VIDEO

KS_DATARANGE_MPEG2_VIDEO

DataFormat Structure

KS_DATAFORMAT_VIDEO (frames only)

KS_DATAFORMAT_VIDEO2 (fields or frames, bob or weave settings)

KS_MPEG1VIDEOINFO (for MPEG1)

KS_MPEGVIDEOINFO2 (for MPEG2)

Major Format GUID

KSDATAFORMAT_TYPE_VIDEO

Sub-Format GUID

RGB16, RGB24, UYVY, JPEG

Specifier GUID

KSDATAFORMAT_SPECIFIER_VIDEOINFO (frames only)

KSDATAFORMAT_SPECIFIER_VIDEOINFO2 (fields or frames)

Extended Header Size

KS_FRAME_INFO if not an MPEG format. Zero if an MPEG format.

Required Property Sets

KSPROPSETID_Connection

PROPSETID_VIDCAP_DROPPEDFRAMES

Required Event Sets

None

DirectShow majortype

MEDIATYPE_Video

DirectShow formattype

FORMAT_VideoInfo (frames only)

FORMAT_VideoInfo2 (fields or frames)