LPCM vs. TrueHD

[Ascended_Saiyan]

I have read how these new compressed lossless formats (TrueHD in particular) are suppose to be...well...lossless. I have noticed a difference between TrueHD and LPCM on "Stomp the Yard" (thanks, Sony). It seems like some of the fidelity is subdued. Other reviewers have noticed this difference on the "Departed" between the HD DVD (TrueHD) and the Blu-ray (LPCM) versions.

Could it be that TrueHD isn't quite lossless but close to it? All I know is that from now on I want a LPCM track unless space constraints call for a TrueHD track. Have any of you noticed this as well?

[JTK]

Semi related conversation in this thread sort of. I definitely agree with Peter's post here:

https://forum.blu-ray.com/showthread...9564#post99564

[BTBuck1]

I haven't seen a single HDDVD title in TruHD where I've thought it even held a candle to LPCM 5.1

Funny though, Titles like M,I:3 or Pirates in 640kbps DD...hell even Casino Roayles 448kbps track sound more impressive than anything I have heard from "TruHD"

IMHO from what I have heard so far, TruHD is hardly better than DDplus at 1.5mbps. Yet I am still in shock evertime I select PCM lossless on my sammy

[PeterTHX]

Originally Posted by Ascended_Saiyan

I have read how these new compressed lossless formats (TrueHD in particular) are suppose to be...well...lossless. I have noticed a difference between TrueHD and LPCM on "Stomp the Yard" (thanks, Sony). It seems like some of the fidelity is subdued. Other reviewers have noticed this difference on the "Departed" between the HD DVD (TrueHD) and the Blu-ray (LPCM) versions.

Could it be that TrueHD isn't quite lossless but close to it? All I know is that from now on I want a LPCM track unless space constraints call for a TrueHD track. Have any of you noticed this as well?

Hmmm.

How is your PS3 set?

I don't have "Stomp The Yard" (not my kind of movie) but other reviews I've read listed them as identical.

IMHO from what I have heard so far, TruHD is hardly better than DDplus at 1.5mbps. Yet I am still in shock evertime I select PCM lossless on my sammy

We really need more apples to apples comparisons done on Blu-ray. Perhaps when the "Spider-Man" films are out. Plus the remastered "Fifth Element".

[BTBuck1]

Originally Posted by PeterTHX

We really need more apples to apples comparisons done on Blu-ray. Perhaps when the "Spider-Man" films are out. Plus the remastered "Fifth Element".

LPCM fo life!

[Ascended_Saiyan]

Originally Posted by PeterTHX

Hmmm.

How is your PS3 set?

I don't have "Stomp The Yard" (not my kind of movie) but other reviews I've read listed them as identical.



We really need more apples to apples comparisons done on Blu-ray. Perhaps when the "Spider-Man" films are out. Plus the remastered "Fifth Element".

My PS3 is not set to bitstream. Not to mention even Peter Bracke noticed the difference on "The Departed" (from HD DVD and Blu-ray versions). I don't even think he was using a PS3.

I got curious while watching Iwo Jima with the TrueHD track. I was looking at the bitrates for the TrueHD track and noticed how low they were. I figured this was a complete port from the HD DVD version. That made me think about something. I thought what if all the HD DVD versions of TrueHD was encoded at such a low bitrate. That made me take out every title in my collection with a TrueHD track. The most direct comparison being "Stomp the Yard". To be continued...typing on the PS3

[Ascended_Saiyan]

On "Stomp the Yard", I noticed that the bitrates on the TrueHD track was much higher than the bitrates on the "Letters from Iwo Jima" TrueHD track.

I popped in the Nine Inch Nails concert. The TrueHD track was at a higher bitrate level than a 5.1 LPCM at 4.6Mbps. The TrueHD track on "Jazz Legends" was almost as high as the Nine Inch Nails concert. I should also point out that the last two titles I mentioned sounded everybit as good as any 5.1 LPCM track or even slightly better (it should sound that way at the same or higher bitrate as a 16-bit 5.1 LPCM track).

Therefore, my theory is that the HD DVD TrueHD tracks maybe compressed to the point where they are no longer lossless.

[PeterTHX]

Originally Posted by Ascended_Saiyan

On "Stomp the Yard", I noticed that the bitrates on the TrueHD track was much higher than the bitrates on the "Letters from Iwo Jima" TrueHD track.

I popped in the Nine Inch Nails concert. The TrueHD track was at a higher bitrate level than a 5.1 LPCM at 4.6Mbps. The TrueHD track on "Jazz Legends" was almost as high as the Nine Inch Nails concert. I should also point out that the last two titles I mentioned sounded everybit as good as any 5.1 LPCM track or even slightly better (it should sound that way at the same or higher bitrate as a 16-bit 5.1 LPCM track).

Therefore, my theory is that the HD DVD TrueHD tracks maybe compressed to the point where they are no longer lossless.

It depends: the titles you mention are music tracks. Music is much more nuanced and demanding, compare a soundtrack CD to the film version, not even close.
BTW: Watch the bitrate jump on "Iwo Jima" when things get busy, especially when the music kicks in.

[Ascended_Saiyan]

Originally Posted by PeterTHX

It depends: the titles you mention are music tracks. Music is much more nuanced and demanding, compare a soundtrack CD to the film version, not even close.
BTW: Watch the bitrate jump on "Iwo Jima" when things get busy, especially when the music kicks in.

I watched that meter the entire time during "Letters from Iwo Jima". It never got to 2.8Mbps. It mainly hung around 1.2Mbps. Plus, it sounded subdued...like the edges were rounded off. "Stomp the Yard" almost never went below 1.7 and peaked in the 3+Mbps range. But, that TrueHD track sounded subdued as well.

[PeterTHX]

I watched that meter the entire time during "Letters from Iwo Jima". It never got to 2.8Mbps

Weird. I got 3.1Mbps peaks.

[Ascended_Saiyan]

Originally Posted by PeterTHX

Weird. I got 3.1Mbps peaks.

On what parts did you get 3.1Mbps? I will revisit the movie if you let me know where to look.

[PeterTHX]

Originally Posted by Ascended_Saiyan

On what parts did you get 3.1Mbps? I will revisit the movie if you let me know where to look.

They're here and there. Like 0:44:14 (there's a few 3+ peaks in that bombing), 0:58:56, usually explosions. Lots of texture in those.

1:25:01, the big boom actually registered 3.2 Mbps.

I think it samples it every few seconds, because when I start it at different points I get different readings. So depends on what point you "start" at.

"Iwo Jima" is a quiet soundtrack anyway, especially for a war film. I think Eastwood wanted it that way. It's never overpowering at any time the same way "Saving Private Ryan" was.

[Ascended_Saiyan]

Originally Posted by PeterTHX

They're here and there. Like 0:44:14 (there's a few 3+ peaks in that bombing), 0:58:56, usually explosions. Lots of texture in those.

1:25:01, the big boom actually registered 3.2 Mbps.

I think it samples it every few seconds, because when I start it at different points I get different readings. So depends on what point you "start" at.

"Iwo Jima" is a quiet soundtrack anyway, especially for a war film. I think Eastwood wanted it that way. It's never overpowering at any time the same way "Saving Private Ryan" was.

It did hit 3.1 and 3.2 for about 1/10 of a second. That's probably why I missed it.

"Letters from Iwo Jima" may have been a quiet movie, but it still sounds like the edges are rounded off (subdued). I don't think anything will change that. I was like to see the TrueHD bitrates on all their titles. I want to see if those encodes are more like "Letters from Iwo Jima". If so, I can basically assume that most HD DVD titles don't sound as natural as LPCM.

[NutsAboutPS3]

TrueHD is lossless, so will be identical to the uncompressed sound track it was made from. The only way it can sound different to an uncompressed track is if it wasn't made from that uncompressed track, i.e. they differ in some way other than the fact that one is uncompressed and one is TrueHD:
http://www.dolby.com/consumer/technology/trueHD.html

In this respect it's just like using pkzip, and nobody ever complains that their data files just don't seem the same after they've been compressed and extracted from a zip file.

The only way to do a fair comparison is to take an uncompressed track from a Blu-ray disc, encode it to TrueHD, then burn both tracks back to disc and listen to them. This is the only way you can know that you're listening to the same audio track.

[PeterTHX]

"Letters from Iwo Jima" may have been a quiet movie, but it still sounds like the edges are rounded off

Weird. Sounds plenty crisp here, and I have the Cinema ReEQ engaged!
Onkyo TX-SR803 via HDMI.

[aaronwt]

Originally Posted by Ascended_Saiyan

I watched that meter the entire time during "Letters from Iwo Jima". It never got to 2.8Mbps. It mainly hung around 1.2Mbps. Plus, it sounded subdued...like the edges were rounded off. "Stomp the Yard" almost never went below 1.7 and peaked in the 3+Mbps range. But, that TrueHD track sounded subdued as well.

Why would you watch a bitrate meter during the entire movie?

[LembasBread]

Originally Posted by Ascended_Saiyan

I popped in the Nine Inch Nails concert. The TrueHD track was at a higher bitrate level than a 5.1 LPCM at 4.6Mbps. The TrueHD track on "Jazz Legends" was almost as high as the Nine Inch Nails concert.

Perhaps those discs are 24-bit TrueHD tracks. This would make sense as they are music oriented titles.

[dialog_gvf]

Originally Posted by PeterTHX

They're here and there. Like 0:44:14 (there's a few 3+ peaks in that bombing), 0:58:56, usually explosions. Lots of texture in those.

Hmmm, what is that mess I see in the dust of the explosion that starts at 0:44:14?

Gary

[PeterTHX]

Originally Posted by dialog_gvf

Hmmm, what is that mess I see in the dust of the explosion that starts at 0:44:14?

Gary

Heh. I was referring to the sound texture

[Ascended_Saiyan]

Originally Posted by NutsAboutPS3

The only way to do a fair comparison is to take an uncompressed track from a Blu-ray disc, encode it to TrueHD, then burn both tracks back to disc and listen to them. This is the only way you can know that you're listening to the same audio track.

You mean like on "Stomp the Yard"?

Look, I know TrueHD is suppose to be lossless. I've gone through the white papers, too. I'm saying my ears tell me something different than the paperwork. I don't believe my ears are all that special. I believe my eyes over what is written. Just buy or rent "Stomp the Yard" for a direct comparison. I'm not the only one that has noticed this. BTBuck has noticed this, and so has Peter Bracke (highdefdigest) on "The Departed". Read the audio portion of the review.

Do your own tests and post how sensitive your ears are in the thread. Thanks.