DolbyDigital DVD

Hey gang,

I assume others also have the DolbyDigital DVD offered by Dolby to show off your HT systems. It's nice to have the trailers and some misc. audio to show off the sound, definately. I hoped to get the newer Consumer version, but it is still not available, and a call to Dolby revealed they are still not ready to sell yet.

I am going to show my ignorance in regards to the audio bits they also supply on the disc. I listened to some of them, but am not sure what some of the items are for. Anyone know of a good reference for this kind of test signal stuff, maybe some definitions and explainations to why I, the HT owner, need to use them to test and calibrate my system?

I don't have any fancy test equipment or pink-noise analyzers or anything of that nature. Just my ears, which are the only thing I have to make happy.

Thanks in advance for the help,

r

robn kester
flow@mac.com

Where did you get that Dolby DVD?

I too would be interested in knowing where you got the DVD from as Dolby (as far as I am aware) have not released a test disc for consumer use. If you have happened upon the test disc distributed for professional use then please treat the signals with caution as, if used incorrectly, they can damage your system quite severely. If you want a 'demo' disc for the home then please purchase 'The Ultimate DVD' rather than use a disc pressed especially for the trade.

Justin Pledger
Dolby Laboratories

Hello again,

To answer both of your questions, I got the DVD from Dolby directly. I found it on their site, called the store directly and asked if this was available to consumers. The gal said yes so I ordered it. I really wanted the consumer version, but she said it was not going to be available for a while.

The DVD is listed under the retailer/licensee products. From the main menu at dolby.com, goto "dvd", the choose "Dolby DVD Demo and Test Disc." Runs about $40.

I am curious as to what the different test signals are for, and which ones might harm my system or my hearing. I've not played with them too much due to the possible damage that I was told could occur. If someone knows of a good source for this info, it would be appreciated.

r
flow@mac.com

BTW, here's the short description for the Consumer DVD they are going to be releasing. It sounds like it will contain the same items as on the Retail DVD:

Coming Soon!
DVD - "We've Got the Whole World Listening"
This new Dolby DVD contains a history of Dolby, the Dolby Digital story, five Dolby trailers (Rain, City, Train, Canyon, & Egypt) , and sample music in multiple formats for comparison.

It would be nice if they put out a disc with the DD trailers and then the top 5-10 movie trailers that were available at that moment to really show off your system.

r
flow@mac.com

Dear Robin
If you want to email me directly then I'd be happy to take you through what each of the individual tones are for. If there's a call for it - then I'd be happy to post this on the forum. However, due to the length it would be better if you could get in touch directly Robin.

Cheers

Justin
Dolby Laboratories

[Taxi]

Justin, definitely post this for everybody to see. Don't worry about the length. If it's good info, we want it.

Thanks!

Taxi
DDS#42

OK. I will compile it later today and post it tomorrow - warning - It will be long (I think)!

[Dominik Pfleghaar]

Justin,

don't worry about the length. We have the bandwith

------------------
Unca Dom, DDS-088
dvdfile.com administrator
dominikpfleghaar@netscape.net

Justin,

Please do post them to the forum, I think we all want to know.

And thanks for doing so, I appreciate it!

r
flow@mac.com

Hello -

This is taking longer than I anticipated! I will post all the info tomorrow, I promise. Hope that's OK.

Justin

<>

Is with me. I got nuttin but time. (and rosemary and sage.)

r

My apologies for the delay in coming back to you. I am posting the information below with some trepidation to be fank as on another part of this forum I am being accused of lying, therefore if any further information is required I have been directed to request that you go the Dolby website at www.dolby.com where you will find lots and lots of information on setting up your home cinema system. That information's veracity will, we hope, not be questioned. There is a new DVD out for consumer use called 'We've Got the Whole World Listening'. This is ideal to show off your system and contains all the trailers, which seems to be the main reason people want the test disc. The following information will explain to you what the Professional Dolby Digital Test Disc Version 1.0 actually does. It is complicated, so bear with me and I shall try to explain as best I can. To be honest if you aren't familiar with audio engineering and do not have the relevant test equipment - most of the following will be pretty useless to you.

Test Disc Version 1.0

The disc contains a wide range of signals that will assist in the testing of products using Dolby Digital Audio, including:

1) 6 minute story on the basics
2) 4 trailers for your enjoyment!!!
3) Music clips to demo the potential for non-
picture programming
4) Audio test tones for evaluating DVD
players, AV Decoders, and Dolby Digtal
operation
5) Digitally mastered video test signals for
basic performance evaluations.

The disc is divided into titles which are then sub-divided into chapters. There are a few titkes (39,40 and 79) that were designed to test specific functionality of DVD players. The type of test signals in these titles is not necessarily caompatible with standard DVD audio content. These signals were intentionally added to the test material to exercise specific areas of a Dolby Digital Decoder. Title 78 contains deliberately corrupted data. Your decoder will mute sporadically. This is normal.

There are also some mistakes on the disc - oops! Title 62: LFE not present in dialnorm test and title 54: Chapters 5 and 6 show 3/2 listening when the audio is infact 2/1. Never mind!!

Now onto the science!!

Sampling rate: 48kHz, Bitrate: 448 kbps, 5.1 channels; 192 kbps2 channels, Word Length: 16 bits, unless otherwise noted
Bandwidth: 20.30 kHz, Coupling on at 14.67 kHz
The disc was encoded using DP561A AC-3 Encoder version 5.02. or software encoder version 4.05
DC Filter off
Original Bitstream
dynrng: off, unless otherwise stated
LFE filter 120 Hz on / -3dB input att.off
The disc is not copyrighted


OK - now onto the individual titles. I won't go through each individual chapter on things such as the trailers (which I'm sure are self explanatory) or we'll be here all day!!

Part One: Dolby Digital Story
This is the part of the disc that gives a bit of background info - there are 8 chapters in all top and tailed by trailers!

Part Two: Additional Trailers
Wahey - this is the bit everyone loves. This is probably what the disc is best used for to be honest, checking out those trailers!

Part Three: Additional Music and Demo Material
Bit of nice 5.1 music really - sounds good eh?!

Part Four: 2 Channel Test Signals
OK - this is where things get complicated. This section is for use with test instumentation only for calibrating system gain. You should not access these titles without proper instrumentation.
Titles:

7. This is a reference tone from your left and right speakers at 400Hz at -20 dBFS in both channels. It lasts for 30 seconds.

8. This is another reference tone at 997 Hz at - 20dBFS again in both L and R channels.

9. Yet another reference tone this time at 2 kHz at - 20dBFS - 2000 Hz from both L and R speakers.

The following titles are for measuring your decoder's dynamic range across frequencies. L and R channels only. You need test equipment for these too.

10. L and R at 20 Hz at - 60 dBFS
11 "" "" at 200 Hz at - 60 dBFS
12 "" "" at 200 Hz at - 60 dBFS
13 "" "" "" ""
14 The same
15. The same
16 MTone at - 60 dBFS

The following titles are used to verify frequency response and are in stepped sweeps - L then R then L and R.

17. Sweep 20 Hz to 20 kHz - 20 dBFS - Left channel
18. Sweep same as above for right channel.
19. Sweep same as above for both channels.

WARNING!!!
The following tests should not be accessed unless you really know what you're doing - they are at high level and may cuase damage to your equipment and/or your hearing. They test your system rather well though. But please don't play around with them - Please!

20. Pink noise is used to measure acoustical output on this title, it lasts for 1 minute and is L and R channel only.

21. This time, white noise is used for the same purpose as above.

The following section is used to verify operation of compression (I am assuming you all know what compression is.)

22. L and R sweep again 400 Hz 0 to - 60 dBFS

The follwing title is used to verify operation of dialogue normalisation. we wil call it Dialnorm. The Dialnorm test is stepped from -31 to 0.

23.The test has a 2 second dwell and is L and R only. It lasts for 1 minute 4 seconds 1 kHz 0 dBFS

24. This will test the linearity of D/A convertors. It is a 4 kHz sine wave fade from 0 dBFS to - 120 dBFS it lasts 2 minutes. L and R only. 4 kHz fade.

25. This is used to verify noise modulation and is a 41 Hz sine wave fade from 0dBFS to - 120 dBFS. L and R only. 41 Hz fade.

Titles 26, 27 and 28 are full scale tones and should be used with instrumentation. The order is L then R then L and R channels. Each at 997 Hz @ FS

Part Five: 5.1 Channel Test signals. The follwoing section will test all channels, unless otherwise stated ( I can't be bothered to keep typing L and R etc) So channles will be L and R and Centre and L Surround and R surround and LFE all at the same frequency, unless otherwise noted.

The firs part is used for calibrating system gain - you'll need those instruments again here.

29. Reference tone 400Hz at -20 dBFS.
400Hz at - 20dBFS - all channels EXCEPT
LFE
30. Reference tone 997Hz at - 20 dBFS.
See above.
31. Reference tone 2kHz at - 20 dBFS.
See above

Hey - we're back to the dynamic range test!

32. All channels at 29Hz at - 60 dBFS
33. All channles at 200Hz (No LFE)
34. The same but at 200Hz
35. Ditto but at 200Hz
36. Yep the same at 2kHz
37. Goodness me! at 20kHz
38. Again?! MTone

39 and 40. The following is a mode and channle check and is best left to run its' course. The multitone is at -20 dBFS on chapter 39 and chapter 40 is voicing for all channels except LFE (obviously)

We are about halfway through and I have some work I must do - I will post the second half later - my fingers are tired!! I hope that's OK and that this is what you guys wanted!...

Back again

OK - where were we?

The following are used to check for proper downmix operation.

Downmix Null Test - Proper AC-3 downmix indicated by no signal.

41. L and R 400Hz at -29dBFS
LS and RS and C 400Hz inverted at
-20dBFS no LFE

42. L 400Hz at -16dBFS
R 400Hz at -27.66dBFS
LS and RS 400Hz inverted at -27.66dBFS
C 400Hz inverted -20dBFS

43-49 are intended for verifying frquency response - all are at the same frequency but run in the following sequence in order of chapter: L channel, Centre channel, Right channel, Left Surround channel, Right Surround channel, LFE channel and then all channels. Sweep 20Hz to 20kHz -20dBFS

The follwing are used to verify operation of Pro-Logic decosing.

Noise sequencer
50. All channels
51. Dolby Surround Left and Right Channel total

The next titles verify the Pro-Logic levels.

Level test.
52. L 2kHz at -20dBFS Left Total
53. L 2kHz at -20dBFS Left

Now we come to the karaoke mode! Yippeee!

Karaoke test material.

Title 54.
Chapters 1-6

I will not go too far into this section as I doubt many of you will ustilise this mode but the frquencies are as follows:
L 1kHz at -20dBFS
R 4kHz at same ref.
LS 2kHz
RS 500Hz
C 8kHz

Another WARNING!!! These signals are at high level and may well damage tour system, not to mention your ears!

The following section is used to verify the polarity. Use with EXTREME CAUTION.

Titles 55, 56 & 57

Polarit 1: Signal for testing absolute polarity of source and decoding products. Asymmetrical tone 400Hz at -20dBFS

Polarit 2: Signal for testing relative delay between channels. 1msec at -20dBFS followed by 39msec at 0 (-999) repeats.

Polarit 3: Signal for testing polarity of reproduction system after loudspeakers using polarity tester. Acoustic polarity test (3 positive, 1 reverse pattern)

58. Pink noise at 0dBFS (12db peak/ms ratio)

59. White noise - same as above

60. Downmix overload test - all channles except LFE 2kHz at 0dBFS

61. Compression control test - all channles except LFE 400Hz sweep 0 to -60dBFS

The following section is used to verify operation of dialogue normalisation. Dialnorm (remember?) is stepped from -31 to 0 while the test tone level remains constant.

62. All channels 1kHz 0dBFS. LFE 100Hz at 0

This section is used to verify linearity of D/A convertors.

63. 4kHz sine wave from 0dBFS to -120dBFS

This section is used to verify Noise Modulation.

64. 41Hz sine wave fade from odBFS to -129dBFS

The titles 65 to 73 are for use with test instrumentation ONLY in measuring distortion.

Part Six: Complex Signals Listening Tests
This is pretty much as it sounds - I have listed below the data rate for those with an eye for the finer details. It is for use in difficult material listening mode.

Fanfare listening material

Material kbps bandwidth coupling
diffmus1.ac3 384 18.1 10.2
diffmus2.ac3 384 20.3 6.8
diffmus3.ac3 384 21.4 5.7
diffmus4.ac3 384 22.6 4.6
diffmus5.ac3 384 23.7 3.4
diffmus6.ac3 448 18.1 10.2
diffmus7.ac3 448 20.3 6.8
diffmus8.ac3 448 21.4 5.7
diffmus9.ac3 448 22.6 4.6
diffmus10.ac3 448 23.7 3.4

Part Seven: Additional Test Signals

This section is used for Video interference testing.

75. 20bit dither on all channels.

76. This section is used for 5 channel/Pro-Logic auto switching testing. The test material is Multitone -20dBFS and switches from 3/2 to Lt/Rt and back to 3/2

77. This is for testing BSI and consists of varying BSI Codes.

78. The following section is intended for error concealment testing and consists of 5 chapters with different types of errors. I have detailed the errors for you.
1. bursts of defective frames every 5 seconds, from 1 defective frame at 5" to 5 frames at 25" (defects in first 5/8 of frame)
2. bursts of defective frame every 1 second, from 1 defective frame at 1" to 29 frames at 29" (defects in first 5/8 of frame)
3. defects only in the last 3/8 of frame (1 - 5, 5 second intervals)
4. 30 sec of alternating good/bad frames (15sec of defects in first 5/8, 15 sec of defects in last 3/8 of frame)
5. Random errors!! (Sound Forge simple synthesis noise) added at approx. -20dB into 30.sec bitstream.
All channels except LFE -20dBFS 400Hz tone.

79. This is a data rate sweep at the following.

L Program mix right LS
96 kbps 96 kbps
112 kbps 112 "
128 " 128 "
160 " 160 "
192 " 192 "
224 " 224 "
256 " 256 "
320 " 320 "
384 " 384 "
448 " 448 "

Part Eight: Credits

Well that's it - a complete guide to the DVD test disc I hope that you have understood and enjoyed it and that it will help some of you. I must stress though that the disc should not be used to calibrate a system unless you really know what you are doing. There are numerous discs out there than will help you to do this - I recommend Joe Kane's Video Essentials it's very easy to use and will help you far more than the Dolby disc. If however, you are an acoustical engineer then I hope this post is of interest.

I will finish by saying, and I do not mean to appear prudish, that this will be my last technical post on this site. I am more than happy to join in a discussion about films and DVDs etc but am not going to be drawn in to slanging matches with other members of this forum as has happened on another section of said forum. I have had not only my integrity and professional ability questioned but have also been called a liar. If there are any out there who would like more technical information and/or advice on the disc or any other aspect of home cinema, please contact me directly and I will be happy to help in any way that I can but for now that's it.

With very best wishes

Justin

Justin,

Thank you for the great info! I appreciate you posting it for us!

r


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robn kester
flow@mac.com
type 11? i keep typing 11 and nothing happens!

BTW,

Anyone notice they officially announced the new Dolby test DVD on the 9th?

Now I have to decide whether I want to sink more money into another test disc...

r


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--
robn kester
flow@mac.com
type 11? i keep typing 11 and nothing happens!

FYI,

The new Dolby DVD is called,
"We've Got the Whole World Listening" and it lists on their site for $15.00, quite nicely priced compared to the Retail test disc.

Part # 230006

r


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--
robn kester
flow@mac.com
type 11? i keep typing 11 and nothing happens!

Sorry, it's me again.

I broke down and bought the new Dolby DVD. It's only $20 with shipping, so I figured what the heck. (I am a sucker for this kind of thing, can you tell.)

If the timing is similar to the last one, it should arrive by the end of next week.

r


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--
robn kester
flow@mac.com
type 11? i keep typing 11 and nothing happens!

[Chromy]

Keep us posted!