Betacam SX

A digital version of Betacam SP introduced in 1996, positioned as a cheaper alternative to Digital Betacam.

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-2 4:2:2 Profile@ML compression, along with four 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.

The Betacam SX system was very successful with newsgathering operations, which had a legacy of Betacam and Betacam SP tapes. Some Betacam SX decks, such as the DNW-A75 or DNW-A50, can natively play and work from the analog tapes interchangeably because they contain both analog and digital playback heads.

Betacam SX uses MPEG-2 4:2:2P@ML compression, in comparison with other similar systems that use 4:1:1 or 4:2:0 coding. It gives better chroma resolution and allows certain postproduction processes such as Chroma-key.

This format compresses the video signal from approximately 180 Mbit/s to only 18 Mbit/s. This means a compression ratio of around 10:1, which is achieved by the use of mild temporal compression, where alternate frames are stored as MPEG I-frames and B-frames, giving rise to an IBIB sequence on tape.

Together with Betacam SX, Sony introduced a generation of the hybrid recorder, allowing the 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 television studio applications, as well to speed up online editing.

Betacam SX also features a good shot mark (a method for qualitative decisions made in the camcorder to be utilized during the editing process) feature that allows marking of each scene for fast scanning of the tape, looking at recorded marks on every single cassette, and showing the markers 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 subsequently generated heat leads to cooling fans being used to keep the camera at a reasonable temperature.

Betacam SX tape shells are bright yellow, but SX recordings may also be found recorded on analog Betacam SP cassettes. Of course, if such a Betacam SP tape with SX recording is inserted into a Betacam SP player, no picture or sound will appear.

Although Betacam SX machines have gone out of production, the format is still used by many newsgathering operations, including CNN, Canada's CTV, Atlanta's WSB-TV, San Diego's KFMB-TV and NBC's operations in the San Francisco Bay Area at KNTV and KSTS. Many news archives still contain SX tapes. In August 2011, Betacam SX tapes were found in Muammar Gaddafi's underground studio in Tripoli. CNN reporter Sara Sidner commented on-air that CNN still uses the same type of tapes.

Adapted from content published on
Last modified on January 26, 2020, 8:36 pm is a service provided by Codecide, a company located in Chicago, IL USA.