RichardMA
Second Unit
- Joined
- Apr 16, 2002
- Messages
- 446
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.
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.
Sounded like the exact same thing as I am experiencing with this disk. Oh, well. Thanx for setting me straight!
