Betacam
From Wikipedia, the free encyclopedia
Betacam is a family of half-inch professional videotape products developed by Sony from 1982 onwards. In casual use, "Betacam" singly is often used to refer to a Betacam camcorder, a Betacam tape, or a Betacam video recorder.
All Betacam variants from Betacam SP forward, 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 S tapes, while VTRs can play both S and L tapes. The cassette shell and case for each Betacam cassette is colored differently depending on the format, allowing 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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[edit] Variants
[edit] Betacam / Betacam SP
The original Betacam format was 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, performing Chroma Time Division Multiplex, or CTDM. 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 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" 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 its BII speed, while it would only yield 30 minutes on a Betacam deck or camcorder.
Betacam was initially introduced as a camera line along with a video cassette player. The first cameras were the BVP-3, which utilized 3 saticon tubes, and the BVP1, which used a single tri-stripe Trinicon tube. Both these cameras could be operated standalone, or with their docking companion VTR, the BVV1, (quickly superseded by the BVV1A) to form the BVW1 (BVW1A) integrated camcorder. Tapes could not be played back in camera except in black and white for viewing in the camera's viewfinder only. Color playback required the studio source deck at first, the BVW10, which could not record, only play back. It was primarily designed as a feeder deck for A/B roll edit systems, usually for editing to a 1" Type C or 3/4" Umatic cassette edit master tape. There was also the BVW20 field playback deck, which was a portable unit with dc power and a handle, that was used to verify color playback of tapes in the field. Unlike the BVW10, it did not have a built in Time Base Corrector, or TBC.
With the popular success of the Betacam system as a news acquisition format, the line was soon extended to include the BVW15 studio player, and the BVW40 Studio Edit Recorder. The BVW15 added Dynamic Tracking which enabled clear still frame and jog playback, something the BVW10 could not deliver. The BVW40 enabled for the first time editing to a Betacam master, and if setup and wired correctly, true component video editing. It was also possible to do machine to machine editing between a BVW10/15 and BVW40 without an edit controller--a single serial cable between the units was all that was required to control the player from the recorder in performing simple assemble and insert editing. Additionally there were two field models introduced, the field recorder BVW25, and the BVW21 play only portable field deck.
At its introduction, many insisted that Betacam remained inferior to the bulkier 1" Type C and B recording, the standard broadcast production format of the late 70s to mid 80s. Additionally, the maximum record time for both the cameras and studio recorders was only half an hour, a severe limitation in television production.
In 1986 Betacam SP was developed, which increased horizontal resolution to 340 lines. While the quality improvement of the format itself was minor, the improvement to the VTRs was enormous, in quality, features, and particularly, the new larger cassette with 90 minutes of recording time. Beta SP (for "Superior Performance") became the industry standard for most TV stations and high-end production houses until the late 1990s. Despite the format's age Beta SP remains a common standard for video post-production. The recording time is the same as for Betacam, 30 and 90 minutes for S and L, respectively. Tape speed is slightly slower in machines working in the 625/50 format, increasing tape duration of 1 minute for every 5 minutes of run time. So, a 90 minute tape will record 108 minutes of video in PAL.
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 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. However, Betacam SP tapes can be used without a problem in ED Beta VCRs, since the ED Beta format uses metal-formulated tape as well.
The new Betacam SP studio decks were the players, the BVW60 and BVW65, with Dynamic Tracking and the Edit Recorders, the BVW70, and the Dynamic Tracking model, the BVW75. The BVV5 was the BetcamSP dockable camera back, which could playback in color if its companion playback adapter was used. A new SP field recorder, the BVW 35, possessed the added benefit of a standard RS422 serial control port that enabled it to be used as an edit feeder deck. Though the four new studio decks could utilize the full 90 minute BetaSP cassettes, the BVW35 remained limited to the original Beta form factor 30 minute cassette shells. Answering a need for a basic office player, Sony also introduced the BVW22, a much less expensive desktop model that could be used for viewing and logging 90 minute cassettes, but could not be configured into an edit system.
Sony followed up the SP Field Recorder with the BVW50, that could record and play the large size 90 minute cassettes. After this, the deck line was relatively stagnant and incredibly popular for a decade, aside from some specialty models that could record digital audio.
Until the introduction of the BVW-200 camera though, the camera and recorder configuration was a docking system. The BVW-200 was an integrated camera recorder system. It sacrificed the flexibility of a docking camera in order to lose a substantial amount of weight. Eventually, non-docking camcorders became the most popular design by the mid 90s.
The final analog BetacamSP camcorder was the BVW600, which paired a camera front section very similar to the one on the DigiBeta DVW700 to a BetaSP recorder. Like every other Betacam camera system, and unlike the DigiBeta DVW700, the camera could not playback in color without the use of an outboard adapter.
In the early 90's a "pro" or "industrial" line of decks was introduced, with model numbers that echoed the naming conventions of Sony's 1970's era Umatic editing decks. These were the PVW2600 edit source feeder and the 2800 edit recorder. These excellent machines primarily lacked the third and fourth audio channels of the BVW series. In the mid nineties, the far less expensive UVW series debuted. These machines were considerably simpler, somewhat lower quality, and were designed primarily to be used as companions to computer systems, and possessed very limited front panel controls, no jog and shuttle, with TBC control available only with extra cost remote TBC controller. These were represented by the UVW1800, a very popular edit recorder, and the UVW1400 and UVW1600 players.
Betacam and Betacam SP tape cassette shells varied in color depending on the manufacturer. Many companies sold Betacam tapes, sometimes of their own manufacture, sometimes rebranded. Fuji, Maxell, Ampex and 3M were just some of the major brands to do so.
Ampex, Thomson_SA and Philips each sold rebranded OEM versions of some of the Sony VTRs and Camcorders at various times in the 1980s and 1990s. Other than nameplates, these models were identical to the Sony models.
[edit] Digital Betacam
Digital Betacam (commonly referred to as Digibeta, d-beta, dbc or simply Digi) 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 resolutions at a bitrate of 90 Mbit/s plus 4 channels of uncompressed 48 kHz / 20 bit PCM-encoded audio. A 5th analog audio track is available for cueing, and a linear timecode track is also used on the tape.
Digital Betacam equipment is the gold standard of formats for standard-definition digital video, and 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 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.
Typically Digital Betacam is found in a blue cassette container.
[edit] Betacam SX
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 uses MPEG-2 4:2:2P@ML compression, in comparison with other similar systems that use 4:1:1 coding. It gives better chroma resolution and allows certain postproduction processes such as Chroma-Key.
This format compresses the video signal from 170Mb/s to only 18Mb/s. It means a compression ratio of almost 10:1, which is quite high. However, it employs temporal compression, recording pair of pictures IBIBIB… where “I” means Intra-coding, while “B” means Biderectional-coding. This strategy allows high quality pictures at low bit-rates.
Together with Betacam SX, Sony introduced a generation of hybrid recorder, allowing use of both tape and disk recording on the same deck, and high speed dubbing from one to another. This was intended to save wear on the video heads for studio applications, as well to speed up online editing.
Betacam SX also features a good shot mark feature, that allows marking of each scene for fast retrieval. A tape deck can scan the tape for recorded marks of each single cassette, and show it to the operator.
The cameras themselves are generally considered by most sound recordists to be quite noisy in operation, possibly because the amount of computer processing power, and subsequent generated heat, leads to cooling fans being used to keep the camera at a reasonable temperature.
Betacam SX tape shells are bright yellow. Betacam SX machines have gone out of production, although the format is still used by some productions, like San Diego's KFMB-TV.
Beta SX was a common format for TV news production and many news archives still contain SX tapes.
[edit] 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 and timecode track. It lacks an analog audio (cue) track as the Digital Betacam, but will read it as channel 7 if used for playback.
Compression is applied in three different formats: 30 (6:1 compression), 40 (4:1 compression) or 50 Mbit/s (3.3:1 compression) which allows different quality/quantity ratios. Video is recorded at MPEG-2 4:2:2 Profile @ ML.
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.
All IMX VTRs can natively playback Betacam SX tapes, and some, such as the MSW-M2000P/1 are capable of playing back Digital Betacam cassettes as well as analog Betacam and Betacam SP cassettes, but they 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. These values are for 525/60 decks, but will extend in 625/50. A 184 minute tape will record for, as the label itself specifies, 220 minutes.
IMX machines feature the same good shot mark function of the Betacam SX.
MPEG IMX tapes are a muted green, however, the new XDCAM format allows recording of MPEG IMX on a tapeless format, Professional Disc
[edit] HDCAM / HDCAM SR
HDCAM, introduced in 1997, is a HD version of Digital Betacam, using an 8-bit DCT compressed 3:1:1 recording, in 1080i-compatible downsampled resolution of 1440x1080, and adding 24p and 23.976 PsF modes. The HDCAM codec uses non-square pixels and as such the recorded 1440x1080 content is upsampled to 1920x1080 on playback. The recorded video bitrate is 144 Mbit/s. Audio is also similar, with 4 channels of AES/EBU 20-bit/48 kHz digital audio. It is used for Sony's cinematic CineAlta range of products.
HDCAM SR, introduced in 2003, uses a higher particle density tape and is capable of recording in 10 bits 4:4:4 RGB with a bitrate of 440 Mbit/s. The increased bitrate (over HDCAM) allows HDCAM SR to capture much more of the full bandwidth of the HDSDI signal (1920x1080). Some HDCAM SR VTRs can also use a 2x mode with an 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 simultaneously. HDCAM SR uses the new MPEG-4 Studio Profile for compression, and expands the number of audio channels up to 12 at 48 kHz/24 bit.
Some HDCAM VTRs play back older Betacam variants, for example, the SRW-5500 from Sony, an HDCAM SR recorder, plays back Digital Betacam and records HDCAM and HDCAM SR tapes, and tape lengths are the same as for Digital Betacam, up to 40 minutes for S and 124 minutes for L tapes. In 24p mode the runtime increases to 50 and 155 minutes, respectively.
HDCAM tapes are black with an orange lid, and HDCAM SR tapes black with a cyan lid.
440 Mbit/s mode is known as SQ, and 880 Mbit/s mode is known as HQ, and this mode has recently become available in stationary models as well as portable models previously available.
[edit] See also
[edit] External links
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| Magnetic tape |
VERA (1952) - 2 inch Quadruplex videotape (1956) - 1 inch type A videotape (1965) - 1/4 inch Akai (1967) - U-matic (1969) - Cartrivision (1972) - Video Cassette Recording (aka VCR) (1972) - V-Cord (1974) - VX (aka "The Great Time Machine") (1974) - Betamax (1975) - 1 inch type B videotape (1976) - 1 inch type C videotape (1976) - VHS (1976) - VK (1977) - SVR (1979) - Video 2000 (1980) - CVC (1980) - VHS-C (1982) - M (1982) - Betacam (1982) - Video8 (1985) - MII (1986) - D1 (1986) - S-VHS (1987) - D2 (1988) - Hi8 (1989) - D3 (1991) - D5 (1994) - Digital-S (D9) (199?) - S-VHS-C (1987) - W-VHS (1992) - DV (1995) - Betacam HDCAM (1997) - D-VHS (1998) - Digital8 (1999) - HDV (2003) |
| Optical discs |
LaserDisc (1978) - Laserfilm (1984) - CD Video - VCD (1993) - DVD-Video (1996) - MiniDVD - CVD (1998) - SVCD (1998) - FMD (2000) - EVD (2003) - FVD (2005) - UMD (2005) - VMD (2006) - HD DVD (2006) - Blu-ray Disc (BD) (2006) - DMD (2006?) - AVCHD (2006) - Tapestry Media (2007) - Total Hi Def (2007) - HVD (TBA) - PH-DVD (TBA) - SVOD (TBA) - Protein-coated disc (TBA) - Two-Photon 3-D (TBA) |
| Grooved Videodiscs |
Baird Television Record aka Phonovision (1927) - TeD (1974) - Capacitance Electronic Disc aka CED (1981) - VHD (1983) |
