XDCAM

XDCAM is tapeless professional video system introduced by Sony in 2003. First two generations, XDCAM and XDCAM HD, utilize the "Professional Disc" as recording media. This disc is similar to Blu-ray disc and holds either 23 GB of data (PFD23, single-sided) or 50 GB (PFD50, double-sided). The third generation, XDCAM EX, uses solid-state SxS cards instead. In September 2008, JVC announced its alliance with Sony to support the XDCAM EX format.

The XDCAM range includes cameras and decks which act as drop-in replacements for traditional VTRs allowing XDCAM discs to be used within a traditional tape-based workflow. These decks can also serve as random access computer drives for easy import of the video data files into non-linear editing (NLE) systems via IEEE 1394 and Ethernet.

Compression methods

The XDCAM format uses multiple compression methods and container formats. Most standard definition XDCAM camcorders can switch from IMX to DVCAM with the flick of a switch, although both DVCAM-only and IMX-only models are available.

IMX (MPEG IMX)

IMX allows recording in standard definition, using MPEG-2 encoding at data rate of 30, 40 or 50 Megabits per second.

MPEG IMX does not use temporal compression, which makes it suitable as an editing format. At 50 Mbit/s it offers visual quality that is comparable to Digital BetacamFact|date=September 2008, and is still suitable for many TV productions, primarily ENG, where the practicality of a non-linear format outweighs Digital Beta's superior colour resolution (10-bit vs. IMX's 8-bit) and lower compression ratio. It is also a popular choice for Reality TelevisionFact|date=September 2008.

DVCAM (DV25)

DVCAM uses standard DV encoding at 25 Mbit/s and maintains compatibility with a large amount of editing systems.

XDCAM HD (XDCAM HD420, MPEG HD420)

The high definition XDCAM HD recording mode utilizes MPEG-2 long-GOP at up to 35 Mbit/s (HQ mode), with 18Mbit/s and 25 Mbit/s as available options. The 18 and 35 Mbit/s formats are VBR, while the 25 Mbit/s format is CBR.

XDCAM HD422 (MPEG HD422)

The third generation of XDCAM utilizes MPEG HD422 codec with video bitrate up to 50 Mbit/s.

Sony has revealed two models of XDCAM HD422 series including PDW-700 camcorder and PDW-HD1500 half size deck, which began shipping in the second half of 2008.

The format has been adopted quickly into HD field production, including for high-profile shows such as Survivor and Cops [ [http://news.sel.sony.com/en/press_room/b2b/broadcast_production/content_create_edit/release/34964.html] ] .

The PDW-U1 drive is the first product available which is compatible with the new XDCAM HD422. With a free of charge firmware upgrade the PDW-U1 is capable of playback and recording XDCAM HD422 (50Mbit/s) material.

Proxy streams

The low resolution proxy is recorded in MPEG-4 at 1.5 Mbit/s with 64 kbit/s for each audio channel. The CIF resolution is used for the proxy recordings.

Recording media

Professional Disc (XDCAM and XDCAM HD)

The Professional Disc was chosen by Sony as its medium for professional non-linear video acquisition for a number of reasons, outlined in their white-paper [http://bssc.sel.sony.com/BroadcastandBusiness/docs/brochures/v2223.pdf "Why Sony Adopted Professional Disc"] .

Essentially the Professional Disc format was deemed to be a suitable, cost effective and easy step forward. The discs are reliable and robust, suitable for field work (something which has previously been a problem with many disc-based systems). Additionally, the cost of media is comparable to existing professional formats.

xS solid-state (XDCAM EX)

A second XDCAM implementation has been developed by Sony called XDCAM EX. Implemented in the PMW-EX1 camera, it offers a similar recording profile to XDCAM HD, but records on SxS memory cards. The codec is employed at either 25Mbit/s for SP mode (1440x1080), or 35Mbit/s for HQ mode (1920x1080). The recorded media is carried in an MP4 file wrapper, versus XDCAM's MXF file wrappersFact|date=September 2008. These differences mean that existing implementations of XDCAM HD codecs in editing applications are not functional with XDCAM EXFact|date=September 2008. However, the EX1's SP mode does retain compatibility as it matches that of HDV (1440x1080 @ 25Mbit/s CBR). The 35Mbit "HQ" implementation is Variable bitrate.

The PMW-EX1 camcorder employs three 1/2-inch "Exmor" CMOS sensors with over 2 million pixels, the camera was exhibited at the NAB (National Association of Broadcasters) 2007 show. It uses an MPEG-2 long-GOP codec when recording to SxS solid-state memory cards, and a 4:2:2 color ratio can be achieved by using a HD-SDI out connectionFact|date=September 2008. It is branded as a member of Sony's CineAlta family of production equipment. The EX1 offers variable framerate modesFact|date=September 2008, from 1 to 60fps (1 to 30fps in 1080p).

The PMW-EX1 made its debut in November 2007 with a street price of just under (US$) 6500.

In April 2008, Sony added a new interchangable-lens camcorder, the PMW-EX3, to its XDCAM EX lineup. The internal components of the EX3 are identical to that of the EX1, but the EX3 is of shoulder mount design, implemented in a fashion much like the Canon XL series. The EX3 retails with a street price of around $8500.

The Future of XDCAM

Sony has published an article at Sony Technology websiteFact|date=September 2008, where Sony outlines the future of XDCAM. Among three goals of XDCAM, higher transfer speed and larger storage capacity seem reasonable, meanwhile Sony also indicates that a new generation of video compression algorithm will be developed for next generation of XDCAM. According to the development cycle of current XDCAM, the next generation of XDCAM (phase 4) should be available in around 2010.

References

* [http://www.sony.co.jp/SonyInfo/technology/technology/theme/xdcam_01.html official information about XDCAM technology and the future]
* [http://bssc.sel.sony.com/BroadcastandBusiness/markets/10014/xdcam_index.shtml Sony's official XDCAM web page]
* [http://www.sony.com.au/objects/PDF/PDWEX1_Brochure.pdf Brochure for the Sony PMW-EX1]
* [http://bssc.sel.sony.com/BroadcastandBusiness/markets/10014/docs/PDW700_HD1500_broch.pdf Preliminary Brochure of Sony XDCAM HD422]

External links

* [http://pro.sony.com.hk/news_showlist.php?id=696 Sony's XDCAM introduction press release]
* [http://xdcam.com.au/modules/news/ XDCAM pro user group]
* [http://www.callboxlive.com/store/sony-guidebook-p-39.html XDCAM EX training DVD]
* [http://www.vasst.com/product.aspx?id=1edca4ce-759d-4e07-877f-b3e5e55f80d5 XDCAM HD Training DVD]

Video storage formats