5.1 ("five point one") is the common name for six channel surround sound multichannel audio systems. 5.1 is now the most commonly used layout in both commercial cinemas and home theaters. It uses five full bandwidth channels and one low-frequency effects channel (the "point one").Dolby Digital, Dolby Pro Logic II, DTS, and SDDS are all commonly 5.1 systems. 5.1 is also the standard surround sound audio component of digital broadcast and music.

All 5.1 systems use the same speaker channels and configuration, having a front left and right, a center channel, and two surround channels.

5.1 dates back to the 1970s (1976) when Dolby Labs modified the track usage of the six analogue magnetic soundtracks on Todd-AO 70mm film prints. Instead of the 5 screen channels and one surround channel of the Todd-AO format, Dolby Stereo 70 mm Six Track provided three screen channels, two surround channels and a low-frequency enhancement channel.

When digital sound was applied to 35mm release prints, starting with Batman Returns in 1992, the same 5.1 layout was adopted. The ability to provide 5.1 sound had been one of the key reasons for using 70mm for prestige screenings. The provision of 5.1 digital sound on 35mm significantly reduced the use of the very expensive 70mm format.

Salman Khan (pronunciation : [səlˈmaːn ˈxaːn]; born Abdul Rashid Salim Salman Khan on 27 December 1965) is an Indian film actor. He has starred in more than 80 Hindi films.

Khan, who made his acting debut with a minor role in the drama Biwi Ho To Aisi (1988), had his first commercial success with the blockbuster Maine Pyar Kiya (1989), for which he won a Filmfare Award for Best Male Debut. He went on to star in some successful Hindi films of those times, such as Saajan (1991), Hum Aapke Hain Koun..! (1994), Karan Arjun (1995), Judwaa (1997), Pyar Kiya To Darna Kya (1998) and Biwi No.1 (1999), having appeared in the highest earning films of seven separate years during his career.

In 1999, Khan won a Filmfare Award for Best Supporting Actor for his extended appearance in Kuch Kuch Hota Hai (1998), and since then has starred in several critical and commercial successes, including Hum Dil De Chuke Sanam (1999), Tere Naam (2003), Mujhse Shaadi Karogi (2004), No Entry (2005), Partner (2007), Wanted (2009), Dabangg (2010), Ready (2011) and Bodyguard (2011), which has become the second highest-grossing Bollywood film of all-time. Khan has thus established himself as one of the most successful actors of Hindi cinema.

Katrina Kaif (born 16 July 1984) is a British Indian actress and former model who appears in Indian films, mainly in the Hindi-language film industry. She has also appeared in Telugu and Malayalam films. She was voted the sexiest Asian woman in the world by Eastern Eye in the years 2008, 2009 and 2010. Being a British citizen, she works in India on an employment visa.

Kaif made her acting debut with Kaizad Gustad's box office bomb Boom (2003). She tasted success in 2007 with Vipul Shah's Namastey London and followed with such films as Anees Bazmee's Welcome (2007), Abbas-Mustan's Race (2008) and Kabir Khan's New York (2009). She has since appeared in critically and commercially successful films like Prakash Jha's political thriller Rajneeti (2010) and Zoya Akhtar's dramedy Zindagi Na Milegi Dobara (2011).

Kaif was born in Hong Kong, to an Indian Kashmiri father, Mohammed Kaif, and an English mother, Susanna Turquotte, both of whom are British citizens. Her parents divorced when she was very young. Kaif once stated, "My dad, unfortunately, and not out of choice, has had no influence on our upbringing, on our religious or social or moral bearings." When she came to India, she changed her surname to Kaif, because it was Indian in origin. Furthermore, Ayesha Shroff has maintained that the actress' original name is Katrina Turquotte. Kaif has seven siblings; a brother and six sisters. From Hong Kong, she and her family moved to China, then to Japan. From there she went to France when she was 8, and thereafter lived for a few months at a time in Switzerland, Poland, Germany, Belgium, and other European countries. Then she moved with her family to Hawaii, and eventually to her mother's home country of England. Although it is often assumed that Kaif is from London, she lived there only for three years before finally moving to Mumbai.