Developed by: Sony. Digital standard definition format.
Launched in: 1995
Used for: news acquisition, video production , consumer (Mini DV only)
a.k.a.: DV, MiniDV, Mini DV
- Small cassettes ( S-size or MiniDV cassettes) , are used for recording baseline DV, DVCAM as well as HDV
- Medium or M-size cassettes are used in professional Panasonic equipment and are often called DVCPRO tapes. Panasonic video recorders that accept medium cassette can play back from and record to medium cassette in different flavors of DVCPRO format; they will also play small cassettes containing DV or DVCAM recording, via an adapter.
- Large or L-size cassettes are accepted by most standalone DV tape recorders and are used in many shoulder-mount camcorders. The L-size cassette can be used in both Sony and Panasonic equipment. Older Sony decks would not play large cassettes with DVCPRO recordings, but newer models can.
- Extra-large cassettes or XL-size have been designed for use in Panasonic equipment and are sometimes called DVCPRO XL. These cassettes are not wide spread, only two models of standalone Panasonic tape recorders can accept them.
DV cassettes can come with a memory-in-cassette (MIC) low capacity EEPROM memory chip.
Magnetic tape used: ¼” metal-formulated magnetic tape
Magnetic tape manufacturers: Sony, Fuji, Maxell, Ampex and 3M
Video recording: DV is an intra-frame video compression scheme, which uses the discrete cosine transform (DCT) to compress video on a frame-by-frame basis.
DV video employs interlaced video scanning with the luminance sampling frequency of 13.5 MHz. This result in 480 scan lines per complete frame for the 60 Hz system, and 576 scan lines per complete frame for the 50 Hz system. In both systems the active area contains 720 pixels per scan line, with 704 pixels used for content and 16 pixels on the sides left for digital blanking. The same frame size is used for 4:3 and 16:9 frame aspect ratios, resulting in different frame aspect ratio for full-screen and widescreen video.
Audio recording: on 4 channels:
- 16-bit linear PCM at 48 kHz sampling rate
- nonlinear 12-bit PCM channels at 32 kHz sampling rate
- 16-bit audio at 44.1 kHz
Digital Interface format: 80-byte Digital Interface Format (DIF) blocks which are multiplexed into a 150-block sequence. DIF blocks are the basic units of DV streams and can be stored as computer files in raw form or wrapped in such file formats as Audio Video Interleave (AVI), QuickTime, and Material Exchange Format (MXF).[ One video frame is formed from either 10 or 12 such sequences, depending on scanning rate, which results in a data rate of about 25 Mbit/s for video, and an additional 1.5 Mbit/s for audio. This results in a compression rate of 5 to 1. When written to tape, each sequence corresponds to one complete track.
Baseline DV employs unlocked audio. This means that the sound may be +/- ⅓ frame out of sync with the video. However, this is the maximum drift of the audio/video synchronization; it is not compounded throughout the recording.
- IEEE 1394 (FireWire, i.LINK) ports for digital video transfer. When video is captured onto a computer it is stored in a container file, which can be either raw DV stream, AVI, WMV or QuickTime. Whichever container is used, the video itself is not re-encoded and represents a complete digital copy of what has been recorded onto tape. If needed, the video can be recorded back to tape to obtain full and lossless copy of the original footage.
- Some camcorders also feature a USB 2.0 port for computer connection. This port is usually used for transferring still images, but not for video transfer. Camcorders that offer video transfer over USB usually do not deliver full DV quality
- High end cameras and VTRs may have additional professional outputs such as SDI, SDTI, or analog component video . All DV variants have a time code but some older or consumer computer applications fail to take advantage of it.