HDCAM
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HDCAM, introduced in 1997, is an HD version of Digital Betacam, using an 8-bit DCT compressed 3:1:1 recording, in 1080i-compatible downsampled resolution of 1440×1080, and adding 24p and 23.976 PsF modes to later models. The HDCAM codec uses non-square pixels and as such the recorded 1440×1080 content is upsampled to 1920×1080 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. Like Betacam, HDCAM tapes are produced in small and large cassette sizes; the small cassette uses the same form factor as the original Betamax.
It is used for some of Sony's cinematic CineAlta range of products.
[edit] HDCAM SR
HDCAM SR was introduced in 2003 and standardised in SMPTE 409M-2005.[1] It uses a higher particle density tape and is capable of recording in 10 bits 4:2:2 or 4:4:4 RGB with a video bitrate of 440 Mbit/s, and a total data rate of approx. 600 Mbit/s.[2] The increased bitrate (over HDCAM) allows HDCAM SR to capture much more of the full bandwidth of the HDSDI signal (1920×1080). Some HDCAM SR VTRs can also use a 2x mode with an even higher video 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.[2] HDCAM SR uses MPEG-4 Part 2 Simple Studio Profile[1] for compression, and expands the number of audio channels up to 12 at 48 kHz/24-bit.
There are 12 channels of audio recorded uncompressed at 24bit 48kHz sampling. Each channel is capable of recording AES/EBU non-audio data.
HDCAM SR is used commonly for HDTV television production. As of 2007, many prime-time network television shows use HDCAM SR as a master recording medium[citation needed].
Some HDCAM VTRs play back older Betacam variants, for example, the Sony SRW-5500 HDCAM SR recorder, plays back and records HDCAM and HDCAM SR tapes and with optional hardware also plays and upconverts Digital Betacam tapes to HD format. 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 studio models (eg. SRW-5800) as well as portable models previously available. In 2008 the SRW-5800 will give the "HQ" 4:4:4 option.
[edit] References
- ^ a b "Sony Broadcast & Professional Research Labs:HDCAM-SR". http://www.sony.co.uk/biz/view/ShowContent.action?site=biz_en_GB&contentId=1177680438056§iontype=BPRL+Products.
- ^ a b Sony HDCAM SR FAQ
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