Sustainability of Digital Formats
Planning for Library of Congress Collections
Sustainability of Digital Formats
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| Introduction | Sustainability Factors | Content Categories | Format Descriptions | Contact | |
| Full name | DV-DIF (Digital Video Digital Interface Format) |
| Description | Interface format for DV, the Digital Video family of related video encodings (DV, DVCAM, and DVCPRO). A frame of data in the DV format stream is divided into several DIF sequences, each of which is composed of an integral number of 80-byte DIF blocks. DIF blocks are the basic units of DV streams, and each block contains a 3-byte ID header that specifies the block type and its position in the DIF sequence. There are five types of DIF blocks: DIF sequence header, Subcode, Video Auxiliary information (VAUX), Audio, and Video. DV-DIF blocks can be stored as files in raw form (.dv or .dif extension) or wrapped in such file formats as AVI, QuickTime, and MXF. DV encoding is described in DV. More information on DV-DIF is provided in Notes below. Comments on this format description are welcome. |
| Production phase | Generally a initial-state or middle-state format. |
| Relationship to other formats | |
| Used by | DV, Digital Video Encoding (DV, DVCAM, DVCPRO) |
| Used by | AVI_DV, AVI, DV Digital Video |
| Used by | QTV_DV, QuickTime Video, DV Digital Video |
| Used by | MXF_GC_DV-DIF, MXF Generic Container Mapped to DV-DIF Data |
| Used by | Other file wrappers, not documented here |
| LC experience or existing holdings | See DV |
| LC preference | See DV |
| Disclosure | See DV |
| Documentation | See DV |
| Adoption | See DV |
| Licensing and patent claims | See DV |
| Transparency | See DV |
| Self-documentation | Pertains to the file format; see the subtypes listed above or the wrappers AVI, QuickTime, and MXF. |
| External dependencies | None for files; see DV for information about videocassette applications. |
| Technical protection considerations | Pertains to the file format; see the subtypes listed above or the wrappers AVI, QuickTime, and MXF. |
| Video elements | ||
| Normal rendering | See DV | |
| Clarity (support for high image resolution) | See DV | |
| Functionality beyond normal video rendering | See DV | |
| Sound elements | ||
| Normal rendering | See DV | |
| Fidelity (support for high audio resolution) | See DV | |
| Support for multiple sound channels | See DV | |
| Functionality beyond normal rendering | See DV |
| Tag type | Value | Note |
| Filename Extension | dv, dif | For unwrapped "raw" files. For wrapped files, see AVI_DV, QTV_DV, and MXF_GC_DV-DIF. |
| Internet Media Type | video/x-dv | For unwrapped "raw" files, from The File Extension Source. For wrapped files, see AVI_DV, QTV_DV, and MXF_GC_DV-DIF. |
| Magic numbers | None discovered for raw files |
| General | SMPTE 383M (MXF Mapping of DV-DIF to Generic Container) reports that single-frame distributions of DV-DIF data are defined in SMPTE 314M, SMPTE 370M, IEC 61834-2 (for a complete list of specification documents, see DV format specifications). SMPTE 383M (page 2) also reports: • For 60-cycle systems, there are ten identical DIF sequences in each DIF channel. • For 50-cycle systems, twelve. Each DIF sequence is assigned to a DIF channel. • For 25 MB/s IEC DV and DV-based compression: one DIF channel. • For 50 MB/s DV-based compression: two channels. • For 100 MB/s DV-based compression: four channels. |
| History |
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