Betacam
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Beta_tape_sizes_2.jpg
Betacam SP L, Betacam SP S, VHS
Betacam is a family of half-inch professional videotape formats developed by Sony from 1982 onwards.
All use the same shape cassettes, meaning vaults and other storage facilities do not have to be changed when upgrading to a new format. The cassettes come in two sizes, S and L. Betacam cameras can only load the S tape, while VCRs can play both S and L tapes. The cassette shell and case for each Betacam cassette is colored differently depending on the format, this allows for easy visual identification. There is also a mechanical key that allows a video tape recorder to tell which format has been inserted.
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Variants
Betacam / Betacam SP
The original Betacam format launched in 1982. It is an analog component format, storing the luminance (Y) in one track and the chrominance (R-Y, B-Y) on another. This splitting of channels provides a crisp, true broadcast quality product with 300 lines of horizontal resolution.
The original Betacam format records on cassettes loaded with oxide-formulated tape, which are exactly the same as its consumer-market oriented predecessor Betamax, which was introduced 7 years earlier by Sony in 1975. A blank Betamax-branded tape can be used on a Betacam deck, and a Betacam-branded tape (not Betacam SP-branded, for reasons mentioned further on in this article) can be used in a Betamax deck.
The only difference between Betamax and Betacam is that the former records in composite format (much like VHS, U-matic, or 1 inch open-reel Type C videotape), while the latter records in component format and at a much higher linear tape speed, resulting in much-higher video and audio quality over Betamax. A typical L-750 length Beta cassette will yield about 3 hours of recording time on a Betamax VCR at it's BII speed, while it would only yield 30 minutes on a Betacam deck or camcorder.
In 1986 Betacam SP was developed, which increased horizontal resolution to 340 lines. Beta SP (for "Superior Performance") became the industry standard for most TV stations and high-end production houses until the late 1990s. The recording time is the same as for Betacam, 30 and 90 minutes for S and L, respectively.
Betacam SP is able to achieve its namesake superior performance over Betacam in the fact that it uses metal-formulated tape, as opposed to Betacam's oxide tape. Sony designed Betacam SP to be partially forward compatible with standard Betacam, with the capability that Betacam SP tapes can be played in older oxide-era Betacam VTRs, but for playback only. Betacam SP-branded tapes cannot be used for recording in consumer Betamax VCRs like oxide Betacam tapes, due to Betacam SP's metal-formulation tape causing the video heads in a Betamax deck to wear prematurely, which are made of a softer material than the heads in a standard Betacam deck.
Betacam and Betacam SP tapes are usually grey.
Digital Betacam
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Digital Betacam (commonly abbreviated to Digibeta or d-beta or dbc) was launched in 1993. It supersedes both Betacam and Betacam SP, while costing significantly less than the D1 format and providing high quality and reliability. S tapes are available with up to 40 minutes running time, and L tapes with up to 124 minutes.
The Digital Betacam format records a DCT-compressed component video signal at 10-bit YUV 4:2:2 sampling in PAL (720x576) or NTSC (720x480) resolutions at a bitrate of 90 Mbit/s plus 4 channels of uncompressed 48KHz PCM-encoded audio. A 5th audio track is available for cueing, and a linear timecode track is also used on the tape.
Some Digital Betacam equipment can also read Betacam and Betacam SP tapes. Along with the identical cassette size, this meant for easy upgrading.
Digital Betacam is considered to be the gold standard of formats for standard-definition digital video, is capable of outperforming cheaper digital formats such as DVCAM and DVCPRO, and associated equipment is comparatively expensive. Panasonic offers the DVCPRO50 competing format, which has similar technical abilities.
Another key element which aided adoption was Sony's implementation of the Serial Digital Interface (SDI) coaxial digital connection on Digital Betacam decks. Facilities could begin using digital signals on their existing coaxial wiring without having to commit to an expensive re-installation.
Digital Betacam tapes are a muted blue.
Betacam SX
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Betacam SX is a digital version of Betacam SP introduced in 1996, positioned as a cheaper alternative to Digital Betacam. It stores video using MPEG 4:2:2 Profile@ML compression, along with 4 channels of 48 KHz 16 bit PCM audio. All Betacam SX equipment is compatible with Betacam SP tapes. S tapes have a recording time up to 62 minutes, and L tapes up to 194 minutes.
Betacam SX tapes are bright yellow.
MPEG IMX
MPEG IMX is a 2001 development of the Digital Betacam format. It uses the MPEG compression system, but at a higher bitrate than Betacam SX. The IMX format allows for a CCIR 601 compliant video signal, with 8 channels of audio as well as cue and timecode tracks.
With its new IMX VTRs, Sony introduced some new technologies including SDTI and e-VTR. SDTI allows for audio, video, timecode, and remote control functions to be transported by a single coaxial cable, while e-VTR technology extends this by allowing the same data to be transported over IP by way of an ethernet interface on the VTR itself.
IMX VTRs such as the MSW-2100M are capable of playing back Digital Betacam cassettes as well as analog Betacam SP cassettes, but can only record to their native IMX cassettes. S tapes are available with up to 60 minutes capacity, and L tapes hold up to 184 minutes.
MPEG IMX tapes are a muted green.
HDCAM / HDCAM SR
HDCAM, introduced in 1997, is a HDTV version of Digital Betacam, also using 10-bit DCT compressed 4:2:2 recording, but in 720p or 1080i-compatible (1440x1080) resolution, and adding 24 and 23.976 PsF modes. The recorded video bitrate is 144 Mbit/s. Audio is also similar, with 4 channels of AES/EBU 20-bit/48 kHz digital audio.
HDCAM SR, introduced in 2003, uses a higher particle density tape and is capable of recording in 4:4:4 RGB with a bitrate of 440 Mbit/s. The increased bitrate (over HDCAM) allows HDCAM SR to capture the full bandwidth (1920x1080) of a 1080i signal. Some HDCAM SR VTRs (SR camcorders are not available) can also use a 2x mode with a even higher bitrate of 880 Mbit/s, allowing for a single 4:4:4 stream at a lower compression or two 4:2:2 video streams simultaniously. HDCAM SR uses the new MPEG-4 Studio Profile for compression, and expands the number of audio channels up to 12. It is used for Sony's cinematic CineAlta range of products.
HDCAM VTRs generally play back all older Betacam variants, and tape lengths are the same as for Digital Betacam, 40 minutes for S and 124 minutes for L tapes.
HDCAM tapes are black with an orange lid, and HDCAM SR tapes black with a cyan lid.
See also
External link
- Sony Business Solutions Systems (http://bssc.sel.sony.com/)
- Betacam PALsite - over 70 pages of information on Betacam, online seit 2000 (http://betacam.palsite.com/)de:Betacam