Dolby Digital Surround EX On DVDs
Dear Gary: I hope you’ll be able to shed some light on this for me. I’ve been asking around and simply can’t get a straight answer on Dolby EX tracks on DVD. (I know I know, I shoulda come to you first!) What I’m trying to find out is this. Even though there’s a bunch of movies that have been released theatrically with a Dolby EX track, they don’t necessarily say they are Dolby Digital Surround EX tracks on the DVD (and simply say Dolby Digital 5.1 surround). What is the difference between a DVD that is listed as, AND carries a Dolby Digital Surround EX encoded track (like the Exorcist or Se7en), and one that just says Dolby Digital 5.1 (like Art Of War, Hollow Man and Bats) but theatrically were in Dolby EX? I was under the impression that the only real benefit of an official EX encoded track on a DVD would be the ability to auto-switch an amp into the Surround EX mode via a flag in the audio bitstream. BUT in my case I must do this manually (my amp’s the Denon AV1SE—the aussie version of the Denon 5800), and I’ve tried this in all sorts of configs with that flag settings). I haven’t come across a single official Dolby Digital Surround EX-encoded DVD that will auto switch, be it Region 1 or 4 DVDs (all DTS ES 6.1 DVDs auto switch though... god bless ’em). The Dolby and THX Web sites have listed ALL the theatrical EX movies as being Dolby Digital Surround EX for DVD, Yet I have asked a few distributors in Australia about this and so far only the Exorcist and Se7en are official EX mixes for Region 4 DVD, with the rest known only to be Dolby Digital 5.1 by each distributor. (They all decode to EX mode nicely with the appropriate matrixed-derived surround back channel info seemingly in tact.) Any info on this would be greatly appreciated. http://dvdownunder.com.au, Matthew_Goldsmith@adc.com
Matt.Goldsmith, DVDown Under
mailto:Matthew_Goldsmith@adc.com
Movie Sound Editor Perry Sun Comments:
If a film sound mix was originally created for the theatrical release with Dolby® Digital Surround EX™ encoding, then that encoding should survive all the way to the DVD release. This should be true as well for the M&E (music and effects) mix, for which the dialogue is not included, for foreign releases. Therefore, if you know for sure that a film was theatrically released with Surround EX, then you should be confident that the DVD soundtrack will be compatible with Surround EX (or DTS®-ES) decoding, even if the DVD labeling fails to indicate as such. Knowing with certainty about theatrical releases with Surround EX could be tricky though, as there have been some film soundtracks that were quietly Surround EX-encoded without public awareness, notably Hollow Man and The Mexican. So far, no DVD titles with Surround EX have included the flag in the Dolby Digital bit stream to trigger a decoder to automatically decode the back surround channel. This is because the capability to include this flag was not available until the release of the latest version of the Dolby Digital encoder earlier this year. However, in addition to DTS-ES Matrix/Discrete 6.1-encoded soundtracks having the flag within the DTS bit stream to auto-trigger decoding, a few Surround EX-encoded soundtracks in DTS also have this flag.
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