1. Visit this thread for your chance to win a selection of Lionsgate action films on UV!
    Dismiss Notice

Serious problem Dolby EX

Discussion in 'Archived Threads 2001-2004' started by RichardMA, Jun 1, 2002.

  1. RichardMA

    RichardMA Second Unit

    Joined:
    Apr 16, 2002
    Messages:
    446
    Likes Received:
    0
    From Dolby's website:

    Dolby has been actively investigating this issue recently, and has identified specific conditions that cause audio dropouts when the Dolby Digital soundtrack is played. The audio dropout problem is caused by an incompatibility between a new set of features added to the Dolby Digital system and certain makes and models of A/V receivers.

    Dolby has regularly incorporated improvements in its professional studio encoders by means of software updates. In our most recent Dolby Digital encoder release, Dolby added several new parameters to the Dolby Digital bitstream, including (among other items) a Dolby Digital Surround EX flag.

    Unfortunately, certain makes and models of A/V receivers contain incompatibilities that cause them to suffer audio dropouts in the presence of these new bitstream flags. Dolby has seen several reports of such problems, and we are still in the process of identifying all of the root issues. However, we have confirmed and characterized one specific problem that seems to be the most widespread.

    Specifically, in some receivers, the digital signal processor (DSP) chip responsible for decoding the Dolby Digital bitstream triggers a control signal output whenever the new bitstream flags are present. In many products, this control signal is active but causes no audio problems. In other products, the receiver responds to this control signal by momentarily muting the audio outputs. This results in frequent audio dropouts (or even continuous muting) whenever the new bitstream flags are encountered.

    As soon as these incompatibilities were identified, Dolby contacted all major DVD authoring facilities and encouraged them to switch off the new bitstream flags as a means of preventing further incompatibilities with the affected decoders. Dolby has also been working closely with the manufacturers of the hardware products and components to fully understand the problems and identify potential solutions in these areas.

    Currently, only a small handful of DVD titles have been released using the new bitstream flags. It is worth noting that none of these titles were mastered incorrectly—the Dolby Digital soundtracks on these discs were created properly in accordance with the new bitstream syntax specification. However, because this new syntax is not compatible with all A/V receiver products, both Dolby and the DVD content industry are working together to avoid releasing any further content in this format.

    If you experience audio dropouts while playing a recently released DVD, you probably have one of the affected receivers. There are four different ways you can still enjoy the picture and the sound.

    1) Change your DVD player configuration to play PCM digital audio instead of Dolby Digital audio through the digital output jack. This way you do not need to change any wiring in the system. Just remember to set it back to play Dolby Digital audio after the movie! (See your DVD player manual for specific instructions on how to change this setting).

    2) Connect your DVD player’s analog audio output jacks to the analog audio inputs on your receiver. Then select the analog audio inputs instead of the digital audio inputs while watching the movie.

    Methods one and two both allow you to listen to the DVD soundtrack in stereo; or you can turn on Pro Logic or Pro Logic II in your receiver for excellent surround sound effects.

    3) If your DVD player has 5.1-channel analog audio outputs, and your receiver has 5.1-channel analog audio inputs, you can connect these together to enjoy fully discrete multichannel sound.

    4) If the DVD disc has an alternative soundtrack option, this may also be used.

    On behalf of our customers who own affected receivers, Dolby and its partners are continuing to work together to identify alternative solutions to this problem. For example, Dolby is currently developing a new version of encoder software that allows the Surround EX flag to be used on future DVDs in a way that is compatible with all existing A/V receivers. This new encoder release will provide a longer-term solution enabling everyone to enjoy Dolby Digital DVD soundtracks, whether they are mastered in stereo, 5.1, or Dolby Digital Surround EX.

    In addition, Dolby and several consumer electronics manufacturers are working to develop a hardware box capable of modifying the Dolby Digital bitstream so as to avoid triggering audio dropout problems in existing decoder products. Further details regarding this solution will be provided as it becomes available.
     
  2. Earl Simpson

    Earl Simpson Supporting Actor

    Joined:
    Jan 12, 2002
    Messages:
    803
    Likes Received:
    0
    Just curious, why can't you just turn off the EX on the receiver, if you have that option and playback in 5.1???
     
  3. Bob_L

    Bob_L Supporting Actor

    Joined:
    May 19, 2001
    Messages:
    891
    Likes Received:
    1
    Real Name:
    Bob Lindstrom
    Hmmm. It's starting to look like ALL future receivers and pre/pros will have to be software upgradable in order to just retain their ability to work properly.

    Welcome to the computer age.
     
  4. MikeyWeitz

    MikeyWeitz Supporting Actor

    Joined:
    Feb 10, 2002
    Messages:
    939
    Likes Received:
    0
    I am have just experienced this 1st hand on the new realease of MIB on my H/K AVR45. Bought 2 copies and they both do it. On my PC they run fine in Non digital.
    At least I now know what it is.
     
  5. Adam Barratt

    Adam Barratt Cinematographer

    Joined:
    Oct 16, 1998
    Messages:
    2,343
    Likes Received:
    1
    Real Name:
    Adam
    Mikey, the problem is restricted to a handful of discs with Dolby Digital Surround EX soundtracks (and one improperly flagged soundtrack). Men In Black's soundtrack is not Dolby Digital Surround EX, nor does the disc carry the problematic EX flag.

    Any dropouts you are hearing are being caused by something else, not the problem described above by Dolby Labs.

    Adam
     
  6. Espen Braathen

    Espen Braathen Stunt Coordinator

    Joined:
    Feb 26, 1999
    Messages:
    77
    Likes Received:
    0
    The sound drop out problem is not related to the "EX flag" but rather a special extension with contains the serial number of the encoder used to encode the DD audio. A bug in the Crystal (if I remember the manufacturer correctly) DSP core will cause the output to mute if this serial number is encoded in the bitstream.

    To avoid a recall of the defective products with this DSP chip, Dolby will rewrite the latest encoder software such that the serial number feature is not used anymore.
     
  7. Earl Simpson

    Earl Simpson Supporting Actor

    Joined:
    Jan 12, 2002
    Messages:
    803
    Likes Received:
    0
    Good news. So enjoy your stuff and play the troubled dvds in 5.1.
     
  8. ThomasL

    ThomasL Supporting Actor

    Joined:
    Mar 13, 2001
    Messages:
    963
    Likes Received:
    0
    Does anyone have a link to a list of the affected titles?

    thanks,


    --tom
     
  9. Ken Seeber

    Ken Seeber Supporting Actor

    Joined:
    Nov 5, 1999
    Messages:
    787
    Likes Received:
    2
     
  10. Jim Tressler

    Jim Tressler Stunt Coordinator

    Joined:
    Dec 12, 2001
    Messages:
    207
    Likes Received:
    0
    Add disney's atlantis (non collector edition)to that list.
     
  11. Lyle_JP

    Lyle_JP Screenwriter

    Joined:
    Oct 5, 2000
    Messages:
    1,009
    Likes Received:
    2
     
  12. MikeyWeitz

    MikeyWeitz Supporting Actor

    Joined:
    Feb 10, 2002
    Messages:
    939
    Likes Received:
    0
    Mikey, the problem is restricted to a handful of discs with Dolby Digital Surround EX soundtracks (and one improperly flagged soundtrack). Men In Black's soundtrack is not Dolby Digital Surround EX, nor does the disc carry the problematic EX flag.
    Damn, I guess the truth hurts [​IMG] Sounded like the exact same thing as I am experiencing with this disk. Oh, well. Thanx for setting me straight!
     
  13. Lyle_JP

    Lyle_JP Screenwriter

    Joined:
    Oct 5, 2000
    Messages:
    1,009
    Likes Received:
    2
     
  14. MikhailL

    MikhailL Extra

    Joined:
    Jun 2, 2002
    Messages:
    17
    Likes Received:
    0
    It's probably too late to ask, but I've had the same problem (audio drop outs) with my Pioneer Elite amp connected Apex600A DVD player. I always assumed it was the player's problem, since it was working fine with other sources (players or DD movies on digital cable).
    Is this related to amp's DSP decoder problem above?
    Anyone know of a way to fix it?

    thanks.
     
  15. Patrick R. Sklenar

    Patrick R. Sklenar Second Unit

    Joined:
    Jan 25, 2000
    Messages:
    330
    Likes Received:
    0
    Is this the same problem that developed back around last Thanksgiving when Pearl Harbor & Jurassic Park III were released? Or is this something new?
     
  16. Jim Tressler

    Jim Tressler Stunt Coordinator

    Joined:
    Dec 12, 2001
    Messages:
    207
    Likes Received:
    0
    I should have been more clear.. the collectors edition has a dts track as well. I think. My fault.

     

Share This Page