AV/C Streaming Format GUIDs
Like any kernel streaming driver, an AV/C Streaming subunit driver specifies the range of data formats that it supports for each pin by using format GUIDs. A kernel streaming application then uses these format GUIDs to perform a data range intersection for a particular data format. The result is a filled-in KSDATAFORMAT structure. Data intersection is described further in Data Range Intersections in AVStream.
A KSDATAFORMAT structure specifies GUIDs for its major format, format subtype, and specifier. The specifier designates the extended-data structure that follows the KSDATAFORMAT structure in memory. For example, suppose that a data format has a major format of KSDATAFORMAT_TYPE_INTERLEAVED, a format subtype of KSDATAFORMAT_SUBTYPE_DVSD, and a specifier of KSDATAFORMAT_SPECIFIER_DVINFO. In this case, the extended-data structure is the DVINFO structure.
The avcstrm.h header file defines the following streaming format GUIDs:
| GUID | Description |
|---|---|
| KSDATAFORMAT_TYPE_INTERLEAVED | Designates an interleaved audio and video signal. Any video stream that contains audio should specify this GUID as the stream's type. |
| KSDATAFORMAT_TYPE_MPEG2_TRANSPORT_STRIDE | Designates an MPEG2 stream type that deviates from the normal 188-byte MPEG2 packet size. The KSDATAFORMAT_TYPE_MPEG2_TRANSPORT_STRIDE type is used with streams that conform to the IEC 61883-4 specification. These streams use the MPEG2_TRANSPORT_STRIDE structure that allows for the stream to describe the format that is different than the typical 188 byte packet. For example, the dwOffset member of the MPEG2_TRANSPORT_STRIDE would be set to 4, the dwPacketLength member to 188, and the dwStride member to 192. |
| KSDATAFORMAT_SUBTYPE_DVSD | Designates an IEC 61883-2 standard-definition 25-Mbps DV signal that uses a 4:1:1 sampling structure for NTSC signals or that uses a 4:2:0 sampling structure for PAL signals. This format subtype uses the DVINFO structure as the data format's extended-data structure. |
| KSDATAFORMAT_SUBTYPE_DVSL | Designates an IEC 61883-3 long-play 12.5-Mbps DVSD signal, which has the same number of lines as the NTSC or PAL signal but implements a higher compression ratio. This format subtype uses the DVINFO structure as the data format's extended-data structure. |
| KSDATAFORMAT_SUBTYPE_DVHD | Designates an IEC 61883-3 high-definition DV signal, such as a 1125-line 60-Hz NTSC signal or a 1250-line 50-Hz PAL signal. This format subtype is not currently supported. |
| KSDATAFORMAT_SUBTYPE_DV25 | Designates an SMPTE 314M 25-Mbps DVCPRO video signal that uses a 4:1:1 sampling structure for both NTSC and PAL signals. This format subtype uses the DVINFO structure as the data format's extended-data structure. |
| KSDATAFORMAT_SUBTYPE_DV50 | Designates an SMPTE 314M 50-Mbps DVCPRO50 video signal that uses a 4:2:2 sample structure for both NTSC and PAL signals. This format subtype uses the DVINFO structure as the data format's extended-data structure. |
| KSDATAFORMAT_SUBTYPE_DVH1 | Designates an SMPTE 370M 100-Mbps high-definition DV video signal, such as a 720p (progressive) or a 1080i (interlaced) signal. This format subtype uses the DVINFO structure as the data format's extended-data structure. |
| KSDATAFORMAT_SPECIFIER_DVINFO | Designates the DVINFO structure as the extended-data structure following the KSDATAFORMAT in memory. |
| KSDATAFORMAT_SPECIFIER_DV_AVC | Designates the DVINFO and AVCCONNECTINFO structures as the extended-data structures following the KSDATAFORMAT in memory. |
| KSDATAFORMAT_SPECIFIER_AVC | Designates the AVCCONNECTINFO structure as the extended-data structure following the KSDATAFORMAT in memory. This specifier may also be used with an MPEG2TS format, depending on the format's subtype. |
| KSDATAFORMAT_SPECIFIER_61883_4 | Designates an MPEG2-TS format that follows the IEC 61883-4 protocol. This specifier does not use any extended data structure to follow the KSDATAFORMAT in memory. |
Comments
Avcstrm.sys and Msdv.sys support the KSDATAFORMAT_SUBTYPE_DV25, KSDATAFORMAT_SUBTYPE_DV50 and KSDATAFORMAT_SUBTYPE_DVH1 format subtypes in Windows Vista, Windows Server 2003 with Service Pack 1 (SP1), and Windows XP with Service Pack 2 (SP2) operating systems.
Note that the KSDATAFORMAT_SUBTYPE_DVSD and KSDATAFORMAT_SUBTYPE_DV25 format subtypes are compatible using 4:1:1 sampling for NTSC. However, the KSDATAFORMAT_SUBTYPE_DV25 for the PAL format uses 4:1:1 sampling but the KSDATAFORMAT_SUBTYPE_DVSD for the PAL format uses 4:2:0 sampling, thus the distinction between DVSD and DV25.
A subunit driver indicates the frame size (sample size) by the combination of its format subtype and its extended-data structure. For example, the combination of the KSDATAFORMAT_SUBTYPE_DVSD format subtype and the NTSC bit set in the DVINFO extended-data structure indicates a DV frame size of 120 KB.
The KSDATAFORMAT structure contains a FormatSize member that is used to validate the extended-data structure size. That is, in valid extended-data structure sizes FormatSize equals sizeof(KSDATAFORMAT) + sizeof(extended-data structure(s)).
The following table describes the KS data format specifier GUIDs and their corresponding extended-data structures.
| KS data format specifier | Extended-data structure |
|---|---|
| KSDATAFORMAT_SPECIFIER_DVINFO | DVINFO |
| KSDATAFORMAT_SPECIFIER_DV_AVC | DVINFO and AVCCONNECTINFO |
| KSDATAFORMAT_SPECIFIER_AVC | AVCCONNECTINFO |
| KSDATAFORMAT_SPECIFIER_61883_4 | No extended data structure is used |
Microsoft Corporation introduced the msdv.sys subunit driver with Windows 98 SE. This driver supports most MiniDV camcorders in both camera mode and VTR (Video Tape Recorder) mode.
Microsoft Corporation introduced the mstape.sys tape subunit driver with Windows Me. This driver supports D-VHS tape decks and MPEG camcorder devices.
Note
Microsoft does not supply a codec to support DVCPro format decoding.