Dolby digital EX bit on DVD

[Pitou]

Hello,

I would like to know if there is a software that can detect if an audio track is in Dolby Digital or Dolby Digital EX

I know that there is a bit somewhere, but don't know in which file.

This because my home theater is supposed to auto-detect which mode to select, based on the DVD disc. (Assuming that newer movie include that bit)

Thank you.

Pitou.

[mpucoder]

The bits (it is a 2-bit field) are in the DD stream itself, as part of the header. Get a copy of a_52a.pdf from www.atsc.org and look in Annex C "dsurexmod" is the name of the field. If you use a digital link the information gets conveyed to your decoder. According to Dolby ( http://www.dolby.com/ht/co_br_0110_ListenersGuideEX.html ) no movies prior to 2001 used EX.

[Pitou]

Got it, I'll use an Hex editor to look at it.

Thanks very very much.

Pitou.

[sonicbox]

FYI: The EX flag is not used on commerical DVD releases due to a bug with many popular/older Dolby Digital decoders chipsets. It is no longer recommended for use by Dolby; only very few discs have it set. Consumers need to turn EX decoding on manually on EX capable content. Feel free to use the flag yourself, but expect some incompatbility.