Thanks this is interesting. But why do you need dialogue normalization in a DVD or Blu ray? -27dB is quite a lot isn't it? by reducing vocal range volume, doesn't the high pitch and low base becomes too loud??

DialNorm - Dialog Normalization - is a setting on Dolby's codecs made so that people without proper speakers or those who are viewing programs amongst sound sensitive neighbors can view movies intelligibly. Meaning, they can hear the dialog without playing it too loud. It is a useful feature but the problem is the default setting - as I understand it - is always ON and it is embeded into the digital bitstream. You need a receiver that can turn off this feature when it is decoding it to be able to hear the master mix. So if you have a basic HTiB, you can't turn DialNorm off.

DTS has a similar feature BUT it is only employed on the decoder, that is to say it is not part of the bitstream. So any DTS decoder will decode the master mix. And if you have sensitive neighbors, they'll suffer. You can turn on DTS' attenuation feature but again, only receivers with such feature can do it.

So which would you prefer? Automatically listening to the master mix or not?


fuad

Thanks for the explanations. I would think mastermix make more sense? Yet ironically this makes DTS sounds sharper while Dolby sounds more natural. So this has nothing to do with SPECIFICALLY how DTS or Dolby master the soundtrack?

Wouldn't the neighbour suffer more from sudden jump in high pitch or loud LFE, when we increase volume in Dolby to hear the vocal clearer?

Thanks

The DTS/Dolby encoder (machine) doesn't master the soundtrack. The soundmixer does.

When the mix is ready to be encoded, the encoding engineer gets to work. HE is the one who makes sure that the right settings on the encoder is used.

Back when DTS first launched for DVD, DTS encoding engineer themselves worked on each DVD release. There were evidence that the mix was different than the one used for Dolby. But now, everyone can use a DTS/Dolby encoder. Some in hardware and some in software.

No, it wouldn't. A simple example of DialNorm is in the form of Astro broadcast. If you've ever watched any movie on HBO/Cinemax/Star Movies you'll notice that it sounds different - that the loudest section is not as it is on DVD/BD. That's because volume attenuation has been applied. This attenuation is applied for both SD and HD versions of HBO. The reason is still the same - for people who do not have 5.1 systems.


fuad

Thanks much for the education. To be precise, what I mean is if we have the same master or sound mix or analogue source, will it sound the same if it goes through DTS or Dolby encoding? Or is there a lot of subjectivity or how the encoding engineer wants the LFE or the surround channel to sound like?

That I can understand why you need dialnorm but like my original question few posts back: "why do you need dialogue normalization in a DVD or Blu ray?" Isn't that redundant to have in DVD or blu ray where there isn't in between commercials etc?

This post has been edited by specuvestor: Dec 14 2010, 06:28 PM

Is there a way to turn off Dial Norm in the AVR?

I noticed many titles will auto apply Dial Norm, but don't know if it is something that can be turned off or not.

If it is DTS HDMA and Dolby TrueHD, the output MUST sound the same as the input. Otherwise they are not truly lossless codecs.

If it's lossy DTS and Dolby Digital, it won't sound the same as the master. It's like comparing a track of 12kbps MP3 and the original track on CD.

The engineers CAN tweak the settings if they are told to do so. But generally they don't because it's not their job to remix the soundtrack at the encoding stage.

Dialnorm is a mandatory setting on Dolby Digital and perhaps Dolby TrueHD. You can't remove it. You can however set it correctly.

DialNorm and volume attenuation are two separate settings. DiaNorm enables dialogue to be at a consistent level/volume so it can be understood better. Volume attenuation limits the dynamic range of a program. They are used together on Astro's broadcast on all channels. On DVDs/BDs, dynamic range limiter is never used either as a default setting on the decoder or as an embedded metadata.

What lee_lnh was correctly explaining about DialNorm and what I fail to properly explain is this:
1) Dialog on the master stem (pre-encode) is ALWAYS around 400Hz to 4kHz frequency.
2) Dialog is leveled at -27dB. That's not subtracting 27dB. That's at level -27dB.
3) The dynamic range of digital sound for movies is 105dB. 0dB is the peak and is actually very loud, where it could be the sound of the thundering alien horn in Spielberg's War of The Worlds. So the dynamic range starts at -100dB and go all the way up to 5dB, where dialog is normally set at level -27dB.

Back when Dolby created Dolby Digital, they envisioned that their codec will be used for HDTV (yes, it was back in the 90s). Back then, commercials and programs had limited dynamic range so the dialog in commercials always get close to 0dB, say like -4dB. This gives them more impact (loud) but not giving them enough latitude to get even louder, which is often used in movies. Because of these differences, Dolby basically decides that since the sound mixers in the movie industry always put dialog at -27dB, commercials must follow suit since they are not the main feature. Instead of pumping up the dialog in TV programs from -27dB to -4dB and have very little dynamic range at the top, the Dolby Digital codec will force the loud dialog in commercials down to level -27dB so that if you go from the movie to commercial to the movie again, you don't have to fiddle with the volume at all. So DialNorm became a mandatory metadata setting where dialog will always stay consistent at a set volume.

DTS don't feel they should make their dialog normalization metadata a mandatory embedment because DTS assumes that sound mixers for movies and commercials would know how to mix their levels properly. So if the encoding engineers don't put it in the metadata or forget to do so, what encoding engineers put into the DTS encoder will come out exactly as the input. If there are errors, the error can be traced at the encoding stage.

The problem with DialNorm as a mandatory setting is that if you want to tweak the setting, you can. The default setting on consumer DD decoder is at -31dB. So if the encoding engineer set it to -27, the 4dB difference means that the volume will be lowered by 4dB. If the engineer forget to reset the encoder from -20 to -31 for 10 movies, the result would mean the sound for all 10 of those movies will be lower by 11dB. Not only that, the DialNorm metadata can also be tweaked by broadcasters. So if the DD was encoded correctly but the broadcasters didn't know what they are doing and set one program at -25 while another at -27, the viewers will hear one program normally and the other too low.

Turning off DialNorm is not a standard feature of AVRs. If you got one that doesn't have it, you're out of luck. I got a DVD that is encoded so low (DialNorm -5?), I had to pump up the volume to near reference level just to hear it and then have to remember NOT to play anything else until I lower the volume again.


fuad

Thanks for the info. It explains the purpose of the Dialnorm well but I am not too sure about the execution as it depends on non-DD encoders (like advertisers) to ensure the adjustment is made for Dialnorm.

If I read you correctly, if we adjust for the Dialnorm, both DTS and DD lossless encoding should sound exactly the same with the same source?

Is that what you experienced in movies that have both DTS and DD options?

If the ads are in PCM stereo, the broadcaster still has to digitize everything including the soundtrack. During the digitization, the audio signal can be analyzed and a value for DialNorm can be suggested. Then the value is used as the DialNorm metada when the ads's audio are encoded.

Advertizers are normally given a specific set of audio and video parameters that their tapes must meet otherwise the broadcaster cannot run the ads.

Well for DTS HDMA, if you don't put in the DialNorm metadata or you forgot to put it in, then output is the same as the source.

For Dolby TrueHD, you must make sure that DialNorm is adjusted according to the DialNorm level indicated on the master before output can sound the same as input. Otherwise the settings might be off.

Hard to say with DVDs as most have one or the other and not both.


fuad

There are some recent DVD with both. What about blu ray then? Specifically what about lossless HD for DTS and DD. Basically this thread is DTS vs DD and just want to know if you have any idea if there is a AQ difference between DTS and DD if using the same source for encoding so we know which one is more superior.

Thanks for that explanation, it's one of the better ones out there and I think I'm beginning to get it about Dial Norm.



So assuming the AVR is properly calibrated, when you set the master volume at 0dB the dialog would be around 78dB (105dB - 27dB) right?


In many blu rays I notice the AVR applying a Dial Norm of +4dB. I always wondered why the number is 4dB so I think the above explains it. As you said, default is -31dB and standard dialog is leveled at -27, so Dial Norm must be +4 in order to bring it back to standard. Is that correct?

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Added on December 16, 2010, 8:51 pmI noticed Ip Man 2 has both True HD and DTS HD MA. But I haven't compared both yet. Maybe this weekend I'll do it.

This post has been edited by jchong: Dec 16 2010, 08:51 PM

Red Cliff has both 3 lossless formats

MP3 FTW!

apart from dialnorm.

another thing to consider for Dolby is Dynamic Range Control (DRC)

most players now have 3 options:

Auto: DRC setting follow bitstream metadata
ON: DRC is always at full or some setting specified by decoder
OFF: No DRC

im lazy to explain about DRC.. there a plenty of resources out there

Guys, may i ask simple question here?

I have myself HTIB which support DolbyDigital and DTS.
Recently i played "Dolby - The Sound Of High Definition Blu-Ray".
Dolby Digital format works fine on my HTIB, but when it came to True-HD testing, my speaker produce 2.1 sound only.
I was hoping it downmix to DolbyDigital instead of 2.1.

I play the movie from:
Xtreamer (HD Audio pass-through) > AV receiver (HTIB) (Dolby and DTS) > 5.1 speaker

So if i want to experience True-HD or DTS-HD MA, i need to upgrade my HTIB/av receiver?

Thanks in advance

what AVR are you using and does it support True-HD?

from what i know.. the True-HD portion (harry potter, nine inch nails, etc) only contains True-HD tracks.
otherwise if the amp does not support. it will juz come out as Dolby Digital 2.1 (is a seperate audio track)

unlike DD+ 7.1 when amp not supported, it will juz take the DD 5.1 portion and decode.
if DD+ is supported, then amp will provide downmix depend on number of speakers enabled on the amp.

LG something. It only stated DD and DTS, i take that as no for True-HD.
I guess my choice is to upgrade my AVR then.
Thanks for the explaination

What lee said is true. Dolby THD tracks are dedicated. If you want Dolby Digital, you have to switch to that track. DTS HDMA and standard DTS are bundled together but they are separate streams that the player would automatically choose if you don't have DTS HDMA decoders.

So since you're playing this using Xtreamer and not the promo BD from Dolby, how sure are you that your downloaded file has the Dolby TrueHD track? It is unlikely that the Dolby Digital decoder in your HTiB can handle the downmix from lossless 7.1/5.1 to 2.1 unless what you have has already been downmixed to Dolby Digital 2.1.


fuad

unless if BD player support Dolby True-HD decoding

then can juz set at BD player to PCM. And will pass over to AV receiver.

like that you still can enjoy Dolby True-HD 5.1