Is DN -27dB on eac3to the same as DN -4dB on BDinfo?

[maldon]

Hi, all!

I’ve found many BDremux (only .mkv) in which DN (Dialog Normalization) is -27dB when I fed eac3to with them,
but if I go to caps-a-holic, BDinfo shows -4dB. So, I suppose those .mkv files were modified. For example, "The dark knight rises":

https://caps-a-holic.com/c.php?d1=11867&d2=11866&c=4674

As you can see on US Bluray, french, spanish and portuguese audios shows DN -4dB:

AUDIO:

Codec Language Bitrate Description
----- -------- ------- -----------
DTS-HD Master Audio English 4018 kbps 5.1 / 48 kHz / 4018 kbps / 24-bit (DTS Core: 5.1 / 48 kHz / 1509 kbps / 24-bit)
Dolby Digital Audio English 192 kbps 2.0 / 48 kHz / 192 kbps / DN -4dB / Dolby Surround
Dolby Digital Audio French 448 kbps 5.1 / 48 kHz / 448 kbps / DN -4dB
Dolby Digital Audio Spanish 448 kbps 5.1 / 48 kHz / 448 kbps / DN -4dB
Dolby Digital Audio Portuguese 448 kbps 5.1 / 48 kHz / 448 kbps / DN -4dB

On eac3to a BDremux of this Blu-ray shows -27dB. I had started to think that those numbers were the same because I always found -27dB when it must be -4dB… until last week.

I’ve found a BDRemux of "Wild at heart":

https://caps-a-holic.com/c.php?d1=4163&d2=12255&c=817

AUDIO:

Codec Language Bitrate Description
----- -------- ------- -----------
DTS-HD Master Audio English 4102 kbps 5.1 / 48 kHz / 4102 kbps / 24-bit (DTS Core: 5.1 / 48 kHz / 1509 kbps / 24-bit / DN -4dB)
DTS-HD Master Audio English 2104 kbps 2.0 / 48 kHz / 2104 kbps / 24-bit (DTS Core: 2.0 / 48 kHz / 1509 kbps / 24-bit / DN -6dB)
DTS-HD Master Audio Spanish 1075 kbps 1.0 / 48 kHz / 1075 kbps / 24-bit (DTS Core: 1.0 / 48 kHz / 768 kbps / 24-bit / DN -1dB)
DTS-HD Master Audio English 2066 kbps 2.0 / 48 kHz / 2066 kbps / 24-bit (DTS Core: 2.0 / 48 kHz / 1509 kbps / 24-bit / DN -6dB)

And, in this case, eac3to shows -4dB on the 5.1 track. Does anyone have an explanation? Anybody knows any other software to see DN?

[tebasuna51]

Both are values stored in headers of AC3 and DTS streams.

In DolbyDigital (AC3) streams docs:

Dialogue Normalization
This 5-bit code indicates how far the average dialogue level is below digital 100 percent. Valid values are 1–31. The value of 0 is reserved. The values of 1 to 31 are interpreted as -1 dB to -31 dB with respect to digital 100 percent.

Then with a AC3 DN of -27 the signal must be scaled in -4 dB (-31 - (-27))

In DTS docs:

Dialog Normalisation Parameter

The dialog normalization gain (DNG), in dB, is specified by the encoder operator and is used to directly scale the decoder outputs samples

Show directly the attenuation needed (-4 dB) instead the relative value to -31 in AC3.

[maldon]

Thanks a lot, tebasuna. I don't know if I got it right…

with DTS:

when BDinfo shows -4dB, eac3to shows -4dB

with Dolby Digital:

when BDinfo shows -4dB, eac3to shows -27d

But, ¿always?

I used BDinfo to scan a FullBluray rip of Terminator 2 and here is the result:

Codec Language Bitrate Description
----- -------- ------- -----------
DTS-HD Master Audio English 0 kbps 5.1-ES / 48 kHz / 24-bit (DTS Core: 5.1-ES / 48 kHz / 1509 kbps / 24-bit)
DTS-HD High-Res Audio Italian 2304 kbps 5.1 / 48 kHz / 2304 kbps / 24-bit (DTS Core: 5.1 / 48 kHz / 1509 kbps / 24-bit)
DTS-HD High-Res Audio Spanish 2304 kbps 5.1 / 48 kHz / 2304 kbps / 24-bit (DTS Core: 5.1 / 48 kHz / 1509 kbps / 24-bit)
Dolby Digital Audio Spanish 224 kbps 2.0 / 48 kHz / 224 kbps / DN -27dB
DTS Audio Portuguese 768 kbps 5.1 / 48 kHz / 768 kbps / 24-bit
Dolby Digital Audio English 224 kbps 2.0 / 48 kHz / 224 kbps / DN -27dB
Dolby Digital Audio English 224 kbps 2.0 / 48 kHz / 224 kbps / DN -27dB / Dolby Surround
Dolby Digital Audio English 224 kbps 2.0 / 48 kHz / 224 kbps / DN -27dB
* DTS Express English 192 kbps 2.0 / 48 kHz / 192 kbps / 24-bit
* DTS Express English 192 kbps 2.0 / 48 kHz / 192 kbps / 24-bit

Why in this case BDinfo is showing -27dB with Dolby Digital instead of -4dB? Maybe the original disc will show -4dB and the FullBluray was modified?

By the way, BDinfo and eac3to specifies DN, is there any alternative software?

[tebasuna51]

Why in this case BDinfo is showing -27dB with Dolby Digital instead of -4dB?

Seems a BDInfo bug, a soft must show the field header value or the meaning of the value, but not one time the value and other the meaning.

Maybe the original disc will show -4dB and the FullBluray was modified?
Nope, only eac3to modify the DN when extract the tracks to cancel it.
In ac3 eac3to put 31 in the header field and in dts put 0, the meaning of both values is no attenuation.

By the way, BDinfo and eac3to specifies DN, is there any alternative software?
A tool to read header of AC3 and DTS (only core) is LeeAudBi (https://forum.doom9.org/showthread.php?p=1522330#post1522330)

[maldon]

Thank you very much, tebasuna51.

By the way, all the original Blu-rays (with DTS and/or Dolby Digital must contain without exception Dialog Normalization?

For example, "Death Proof" on caps-a-holic:

Name: 00007.MPLS
Length: 1:53:36.859 (h:m:s.ms)
Size: 29,754,335,232 bytes
Total Bitrate: 34.92 Mbps

VIDEO:

Codec Bitrate Description
----- ------- -----------
MPEG-4 AVC Video 25879 kbps 1080p / 23.976 fps / 16:9 / High Profile 4.1

AUDIO:

Codec Language Bitrate Description
----- -------- ------- -----------
Dolby TrueHD Audio English 3073 kbps 5.1 / 48 kHz / 3073 kbps / 24-bit (AC3 Embedded: 5.1 / 48 kHz / 640 kbps / 24-bit)
Dolby Digital Audio English 640 kbps 5.1 / 48 kHz / 640 kbps
Dolby Digital Audio French 640 kbps 5.1 / 48 kHz / 640 kbps
Dolby Digital Audio Spanish 640 kbps 5.1 / 48 kHz / 640 kbps
Dolby Digital Audio Italian 640 kbps 5.1 / 48 kHz / 640 kbps

DVDBeaver:

Dolby TrueHD Audio English 3073 kbps 5.1 / 48 kHz / 3073 kbps / 24-bit (AC3 Core: 5.1 / 48 kHz / 640 kbps)
Dolby Digital Audio English 640 kbps 5.1 / 48 kHz / 640 kbps
Dolby Digital Audio French 640 kbps 5.1 / 48 kHz / 640 kbps
Dolby Digital Audio Italian 640 kbps 5.1 / 48 kHz / 640 kbps
Dolby Digital Audio Spanish 640 kbps 5.1 / 48 kHz / 640 kbps

I can’t see DN on those two websites. But I found a BDinfo report on the net with it:

Playlist: 00007.MPLS
Size: 29,754,335,232 bytes
Length: 1:53:36
Total Bitrate: 34.92 Mbps
Video: MPEG-4 AVC Video / 25879 kbps / 1080p / 23.976 fps / 16:9 / High Profile 4.1
Audio: English / Dolby TrueHD Audio / 5.1 / 48 kHz / 3073 kbps / 24-bit (AC3 Embedded: 5.1 / 48 kHz / 640 kbps / DN -4dB)
Audio: English / Dolby Digital Audio / 5.1 / 48 kHz / 640 kbps / DN -4dB
Audio: French / Dolby Digital Audio / 5.1 / 48 kHz / 640 kbps / DN -4dB
Audio: Italian / Dolby Digital Audio / 5.1 / 48 kHz / 640 kbps / DN -4dB
Audio: Spanish / Dolby Digital Audio / 5.1 / 48 kHz / 640 kbps / DN -4dB

It seems to be the same Blu-ray disc; same length, same size, same total bitrate… So, BDinfo can't always detect DN or the guy who pasted the BDinfo report on caps-a-holic erased that information? Maybe some blu-ray editions has DN and some has not?

[tebasuna51]

The DN is not a important parameter, and some report can not show it.