LPCM vs.Dolby TrueHD vs. DTS-HD Master Audio

Considering all three of the choices you listed result in bit-for-bit identical soundtracks, it's like asking whether you prefer to open up files that were compressed using Zip or RAR. BTW, I'm not arguing with you, just plain having fun.

THEY'RE. ALL. LOSSLESS. if your player or receiver can decode them all, it means jack ****. if they can't, your blu-ray player will just decode DTS-HD MA or TrueHD to PCM anyway.

Now if you're talking about making an MKV, I prefer using FLAC because it compresses better.

I prefer TrueHD, because it's format is cleaner and less complicated, DTS-HD MA has a lossy DTS track inside, with a diff contained in external channels, it's complicated, but the decoder has to combine the diff and the DTS to get back the lossless audio, TrueHD takes up less space and can easily be decoupled from it's AC3 extension, unlike DTS-HD MA.

Since this doesn't affect sound quality, on what do you want people to base their answer to your question: "When you purchase a new Blu-Ray and look on the back what are you hoping to see?"

Your original post is the eqivalent of you getting 3 identical documents and then saying that you have a "soft spot" for the one that arrived in a medium sized envelope. Since the documents (soundtracks) are 100% exactly the same, are you asking people to decide based on what size envelope (compression codec) it came in?

Oxymoron, three things that are the same can't ALSO be different (except in quantum mechanics). You have a vivid/subjective imagination but that is the only difference.

Also riddle me this extreme contradiction: How can the DTS-Master track "sound more clear and crisp" than the original master (copy) LPCM track?
Edited by William - 1/18/13 at 4:03pm

PlayNice, perhaps you do not understand that the method of compression is irrelevant. What matters is the PCM produced by decompression. Lossless means the output is identical to the input. TrueHD and dts-MA are simply two different ways to achieve the exact same result. Take the same soundtrack and feed it into the Dolby and DTS encoders and the PCM outputs will be identical.

As I said in my first post, I'm not arguing with you, just plain having fun. The lossless one of course.

You are being fooled by the old attenuation trick that louder = punchier. The TrueHD track's DN metadata is set at -31dB and HD Master is set at -27dB. Simply turn up the volume +4dB on TrueHD (or -4dB on DTS Master)and they will be 100% identical "Punchier".


EDIT: Read here for an understanding of Dialogue Normalization (poor nomenclature, but I didn't name it)

For the sake of accuracy, the numbers are backwards in William's post. The default Dolby dialnorm value is -27, which tells the decoder to attenuate the overall volume by 4dB. The default DTS encoder DN value is 0 (-31), which means no attenuation.

The standard being employed says dialog should be played back at -31dBFS (below full scale). The decoder looks at the DN value in the metadata. The -27 value that Dolby uses by default tells the decoder that dialog is 4dB too high and the software lowers the overall output level. The 0 value that DTS uses by default tells the decoder that dialog is at the correct -31dBFS level and the software does no attenuation.

DN has never worked as intended. It is supposed to level out loudness differences between programs so that the volume doesn't jump up on commercials, for example. But, the person doing the encoding needs to determine the average dialog level of the program and enter that value in the metadata, which rarely happens. The people doing the encoding usually just accept the Dolby and DTS defaults, regardless of the actual dialog level. So, if the same soundtrack is encoded both ways, the DTS version will playback 4dB louder than the Dolby one.
Edited by BIslander - 1/20/13 at 2:33pm

I thought it was the other way around? -31 for DTS and -27 for Dolby (most of the times).

Also I thought they got rid of dialnorm when it came to bluray?

As for which one I prefer? I prefer DTS HD MA because I'm a DTS fanboy. Naw back in the days when I could only output audio with SPDIF with my HTPC, hd ma was the easier one to use with my ISO rips because it would revert to using the core DTS track. If it was Dolby, than I'd have to select the AC3 track manually thru my htpc. Not an issue anymore though.

No. DTS actually added dialnorm to its HD encoder. It is not part of the DTS Surround encoder. The usage hasn't changed much though.

Oh dts lol

So are all Dolby Tracks (TrueHD + AC3) set to -27? From what I can recall I thought the Dolby encoder (if thats what it is called) automatically sets the DN value to -27

DN is a field in the metadata with allowable value from 31 to 1. The person doing the encoding enters a value. Or not. Dolby encoders default to 27. DTS encoders default to 31. Most of the time, encoding engineers simply accept the default values.

A good example of DialNorm being used on DTS tracks is the BD of 'Transformers 2: Revenge of the Fallen', where the Walmart exclusive Big Screen edition plays back 4dB quieter than the regular edition, despite the those two DTS-HD MA soundtracks being identical.

So even though Dolby encoders default at -27, would an AVR still show it as having an offset of -4?
Thanks!

I remember that causing a big stir on the Bluray forums lol.

4 = 31-27, the amount that the decoder attenuates the level so that average dialog plays at the correct -31dBFS.
Edited by BIslander - 1/20/13 at 3:41pm

The player automatically does it or do I need to raise the MV by 4?

The decoder lowers the volume by the amount of the offset. You can counter the attenuation by raising the master volume the same amount.

I understand where the 4 comes from but what I meant was since -27 is the stock setting on the dolby encoder, would the avr still see an offset of -4? or does a setting of -23 show an offset of -4? Appreciate the help!

If the player automatically did it, folks wouldn't be hearing DTS encodes 4dB louder than Dolby encoded tracks. So you have to raise the MV by 4dB on your receiver.

I have to admit that I'm never aware of which tracks have DialNorm and which don't, since I always set the MV to a comfortable level rather than going by a number on the front panel display.

I love looking at that front panel... lol!

btw when is the next GTG? I have a bunch more questions regarding my build!

We all have our hobbies. Is a get together necessary for you to ask questions? Did you misplace your phone?

Don't have your number!

They all will give you the same quality movie experience, the only difference is what is displayed on the avr/preamp.

I'm with you. I feel the discussion itself is very interesting. Sure, lossless is lossless. However the methods used to maintain such, while using different containers begs questions.

Before I render any opinions, I should note that I'm a deeply seasoned audiophile that's had everything from pioneer, denon, onkyo, marantz etc. Current setup is all mark levinson with wilson audio watt puppies and wilson audio center with one watchdog sub. Moving on..

I've done side by side comparisons with FLAC vs et al... My findings have been simple. FLAC performs in the audio space, just as it does on your storage space. It puts a lot into a small container. And that can be heard, at least by me (or perhaps it's the drugs talking). The soundstage sounds closer together and has noticeably less accuracy in reproduction...more distorted perhaps?

Anyway, that's it. Flame away.