This problem lies with movies released post 1994 and before 1999. This is when the 'Indian sound revolution' started. Most films released before this period were in mono so no point talking about those. A handful of films pre-1994 or during 1994 were released in magnetic 4 track stereo(MPK-1989) and optical stereo(Andaz-1994) but they are not important since these prints were probably never used for the dvds anyway.
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I've noticed that when reviewing older titles from Shemaroo , Arsh and Rana mentioned in the post above about true 5.1 and pseudo 5.1. Although the distinction between true 5.1 and pseudo 5.1 is fairly obvious, some films however have never been released in the digital sound format in the first place, so having a 5.1 channel of the same film on dvd is bullshit, it is a fake 5.1 derived from the optical 2.0 track from the print. To the purist (me)
it is not true 5.1. I rather have a Dolby Stereo mix which I can play in Dolby Pro-Logic more accurately on my system.
For example Judaii was released in cinemas in 1997 with only a Dolby SR print. So if a dvd is made and claims it is in Dolby Digital, it is still fake 5.1.
The first non dubbed Hindi movie to be released in DTS was Judwaa. It was released in 1998 and paired with a mono track. So if the dvd claims it is in DD 5.1. True it is in 5.1 but it is mixed for DTS not Dolby Digital. It is like "Dhoodh Mein Pani Milana". Not authentic enough for me. Fake 5.1. Unless it is released in DTS on dvd.
Nowadays you can get software from the internet to mix a stereo track into Dolby Digital. Even DTS can be mixed into Dolby Digital on your computer. I just prefer the one done in the studio by H.Sridhar or a professional and not some clueless guy at the dvd factory.
One of the first few films released in both DTS and Dolby Digital was Arjun Pandit.
There were other films which were released in generic optical stereo (I heard them in stereo in the theaters) but they were very few. Most were mono. Unlike in Hollywood where films if released in digital had a analog stereo track on the same print, In India however some of this films were released in digital sound backed with mono track on the same print.There were a few films released in DTS stereo but I remember Duplicate as one of them. IMDB states Yugpurush as DTS-Stereo but I don't trust IMDB. A lot of the technical information there is inaccurate.
Not an exhaustive list but I wrote this mostly from memory so forgive any inaccuracy.
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1942 - A love story (1994) Dolby Stereo
Bandit Queen (1994) Dolby Stereo
Rangeela (1995) Dolby Stereo
Hum Aapke Hain Kaun (1994) Ultra Stereo
Dilwale Dulhania Le Jayenge (1995) Dolby SR
Trimurti (1995) Dolby Stereo
Ram Shastra (1995) Dolby SR
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Daraar (1996) Dolby SR
Drohi(1996) Re-release as Dolby SR
Ghatak (1996) Dolby SR
Jeet (1996) Dolby SR
Khamoshi (1996) Dolby SR
Saza-E-Kala Pani/Kalapani (dubbed) (1996) Hindi Dolby SR/ Tamil DTS
Loafer(1996)Dolby SR
Maachis(1996)Dolby SR
Prem Granth(1996)Dolby SR
RajKumar(1996)Dolby SR
Hindustani(dubbed)(1996) DTS
Jaan(1996)Ultra Stereo
Mr Bechara(1996)Optical Stereo
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...Aur Pyaar Ho Gaya (1997) DTS
Aflatoon (19997) DTS
Bhai(1997) DTS/Dolby SR
Border (1997)DTS/Dolby SR
Chachi 420 (1997) DTS
Daud (1997) Dolby Digital
Deewana Mastana(1997) Dolby SR
Dil To Pagal Hai (1997) Dolby Digital
Gupt (1997) DTS
Hameshaa (1997) Dolby SR
Himalay Putra (1997) Dolby SR
Ishq (1997) DTS
Judaai (1997) Dolby SR
Koyla (1997) DTS
Lahu Ke Do Rang (1997) Dolby SR
Lav Kush (1997) DTS
Mahaanta (1997) DTS
Mere Sapno Ki Rani (1997) Dolby SR
Mohabbat (1997) Dolby SR
Mrityudaata(1997) DTS/Ultra Stereo
Pardes (1997) Dolby SR
Saat Rang Ke Sapne (1997) Dolby SR
Sapnay (1997) Dolby SR
Virasat (1997) Dolby SR
Ziddi (1997) DTS/Ultra Stereo
Zor (1997) Dolby Digital
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Bade Miyan Chote Miyan (1998) DTS
Bade Dilwala (1998) DTS
Bada Din (1998) Dolby SR
Barood (1998) DTS
Chhota Chetan (1998) DTS
China Gate (1998) DTS
Dil Se (1998) DTS
Doli Saja Ke Rakhna (1998( Dolby SR
Duplicate (1998) DTS Stereo
Dushman (1998) Dolby Digital
Gharwali Baharwali (1998) DTS Stereo
Ghulam (1998) Dolby Digital
Jab Pyar Kisi Se Hota Hai (1998) Dolby SR
Jaya Ganga (1998) Dolby SR
Jeans (1998) DTS
Kuch Kuch Hota Hai (1998) Dolby Digital
Mehndi (1998) DTS
Pyar Kiya To Darna Kya (1998) DTS
Satya (1998) DTS
Salaakhen (1998) DTS
Soldier (1998) Dolby Digital
Yugpurush (1998)?? can't remember
Wajood (1998) Dolby SR
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Arjun Pandit (1999) DTS/Dolby Digital
Baadshah (1999) Dolby Digital
Biwi no 1(1999) DTS
Dillagi (1999) DTS
1947: Earth (1999) Dolby Digital, I don't remeber a DTS mix
Gair (1999) Dolby Digital
Godmother (1999) Dolby SR
Hello Brother (1999) Dolby Digital)
Hote Hote Pyar Hogaya (1999) Dolby SR
Hum Dil De Chuke Sanam (1999) Dolby Digital
Hum Saath-Saath Hain: We Stand United(1999) Dolby Digital/DTS
Hu Tu Tu (1999) DTS
Jaanam Samjha Karo(1999) Dolby SR
Jaanwar (1999) Dolby Digital
Lal Baadshah (1999)DTS
International Khiladi (1999) Dolby SR
Kaun (1999) DTS
Kohram: The Explosion (1999) Dolby Digital
Rockford (1999) DTS
Laawaris (1999) Dolby Digital
Mast (1999) DTS
Mother 98(1999) DTS
Pyar Koi Khel Nahin(1999) Dolby SR
Sangharsh (1999) DTS
Shool (1999) DTS
Silsila Hai Pyar Ka (1999) Dolby SR
Sirf Tum (1999) Dolby Digital/DTS
Suryavansham (1999) DTS
Thakshak (1999) Dolby Digital/DTS
Taal (1999) DTS/Dolby Digital
Vaastav (1999) DTS
After this it didn't matter most films were in Dolby Digital, DTS or both. Thankfully this problem is no more today unless it is a super cheapo production. Most films today are released in both DTS-ES and Dolby Digital -EX mixes with a backward compatible Dolby SR track on the same print. So dvds more or less follow the original mixes. or at least I hope so.