which audio to use PCM or Dolby HD

[ay221]

I know some bd movies have both a pcm audio and Dolby HD. Does the dobly HD sometimes have a higher bit rate and how does one tell?

[tofur69]

If you have an awesome receiver, great speakers PCM and a good ear on your part...PCM all the way. Most people really do not have an ear for that sort of thing but I am going to assume since you are here, you have all of the requirements to run PCM and enjoy it.

[quetzalcoatl]

Originally Posted by ay221

I know some bd movies have both a pcm audio and Dolby HD. Does the dobly HD sometimes have a higher bit rate and how does one tell?

It really depends on your system. What BD player are you using and what receiver do you have. If your receiver will decode the audio most think it is better to bitstream the audio. But if your receiver cannot decode it or your BD player cannot send it then it is really a mute point.

But not all incodes are created equal. What I would consider the best audio disc on the market is Dave Matthews and it is a 24/96 TrueHD track. If you look at the movie section here it tells on most movies what the tracks are.

[dakota81]

Whichever one sounds better. I use optical out, and 2 channel PCM always sounds better than Dolby Digital, but on some titles, The True HD core audio sounds better to me than 2 channel PCM like with The Fifth Element.

[cleric]

Unless your player has an issue with one or the other, they are the same so whatever toots your horn.

[NutsAboutPS3]

Originally Posted by cleric

Unless your player has an issue with one or the other, they are the same so whatever toots your horn.

This isn't true, e.g. on Ghost Rider and Stomp The Yard, for example, they had 16 bit PCM tracks, but they also had 24 bit TrueHD tracks, so in those cases the TrueHD tracks should have been higher quality. There may be others, I only know of those two because paidgeek gave the info out in the insiders thread.

[cleric]

Originally Posted by NutsAboutPS3

This isn't true, e.g. on Ghost Rider and Stomp The Yard, for example, they had 16 bit PCM tracks, but they also had 24 bit TrueHD tracks, so in those cases the TrueHD tracks should have been higher quality. There may be others, I only know of those two because paidgeek gave the info out in the insiders thread.

Yea except in the situation where one has more channels or different sample size.

But all things constant they will sound the same.

[mastertang]

All I know is, True HD etc. is encoded sound, where as PCM is straight sound with no encoding. For all intents and purposes, a PCM track is what a sound mixing studio would be using to master a movie soundtrack. Once the PCM is done, it is encoded to other formats. I watched Gone in 60 Seconds last night in PCM sound, and I can't conceive of anything being able to top the motor sound of that GT500.

[MatrixS2000]

Originally Posted by cleric

Yea except in the situation where one has more channels or different sample size.

But all things constant they will sound the same.

Or if Diagnorm was used on the DTHD track, then again PCM is better.

[Rustmonsteru]

Technically they should both be the same but I prefer PCM. It may be placebo, but it just seems richer sounding to me.

[MOONPHASE]

read this article and you will know


http://www.highdefdigest.com/news/sh...ess_Audio/1233

[blukrank]

I have a Yamaha receiver that has 5.1 Annalog on it and thats what I use when watching movies with The PCM surround track. The sound is very nice.
I plan on getting a receiver with HDMI at some point.

[ay221]

Originally Posted by NutsAboutPS3

This isn't true, e.g. on Ghost Rider and Stomp The Yard, for example, they had 16 bit PCM tracks, but they also had 24 bit TrueHD tracks, so in those cases the TrueHD tracks should have been higher quality. There may be others, I only know of those two because paidgeek gave the info out in the insiders thread.

This is what I am trying to get at. If I look at the Ghost Rider disc box, it list audio as pcm 5.1 and Dolby TrueHD, but doesn't list the bit rates.

I have a new yammy 1800 receiver that handles all the high end codecs and a panny bd30 receiver that can bitstream them all. So I assume then that it is safer to pick the compressed codecs if at least Dolby TRUEHD or DTS-MA is available. Otherwise pick the PCM sound.

[Anthony P]

Does the dobly HD sometimes have a higher bit rate

in this case bitrate does not mean anything. Digital sound has two metrics. One is called word length and the other sampling frequency

The word length can be thought of as precision the values usually seen are 16 and 24 with 20 in third place. this explains how much bit precision there is in every sampling of the sound. (the bigger the better)

The Sampeling frequency. (a number like 48, 96 or 192). Sound like motion is continuous. The same way film cannot really show the motion and takes still pics equally interval, sound samples are taken at equal intervals. The DAC on your equipment at home will then take these pics and try to recreate the true motion of the sound wave.(the bigger the better)

For example most Disney titles have that info on them like (48kHz/24 bit)

Like NutsAboutPS3 pointed out on some titles the DTHD came from a better digital master.

The bitrate does not matter and the answer to the question as asked is no, if the PCM and DTHD used the same digital master DTHD <= PCM. But if the DTHD came from a better master then in theory it can happen, but it is unlikely.

If you start from an analog source you then get a digital master depending on the values inputted for word and frequency. This digital master is PCM and has no compression so is of a constant bitrate (simple calc since we have the word(bits)*sampling frequency (samples/second)* channels). Then that digital sound is compressed into DTHD.

For all intents and purposes, a PCM track is what a sound mixing studio would be using to master a movie soundtrack.

not necessarily, most are done in analog. The thing is that since DTHD is compressed it takes less BW and less space on the disk so a studio could go with a better digital Master then the PCM.
--------------------------------------

personally, because of the reasons mentioned by others my choices are

1) highest bit/frequency
2) if the same pick PCM over DTHD

[Brain Sturgeon]

Originally Posted by Anthony P

personally, because of the reasons mentioned by others my choices are

1) highest bit/frequency
2) if the same pick PCM over DTHD

I would second this with one caveat. What if the PCM and THD soundtrack are both derived from, lets say, a 16 Bit/48kHz master but the THD was resampled at 24 Bit/48kHz with the PCM being left at 16 Bit/48kHz. I seem to remember a BD that had this (T5E? or SM3?). Does resampling to a higher bitrate from an identical master add anything?

My general listening habits have been to select LPCM over any other soundtrack, if it is available; but the word length issue does come into play from time to time. Having heard some multichannel 24/96 tracks on DVDA, I wish the studios would use this more often in BD releases (particularly on music concert material). It is absolutely mind blowing.

[Anthony P]

Does resampling to a higher bitrate from an identical master add anything?

my guess is no except for possibly having better heuristic algorithms in the professional equipment. On the other hand we are talking of a case that you can't realistically know without someone that worked on it telling you. It won’t be on the back cover, it won’t be in the on screen menu it won’t be on the on screen stats (i.e. like the bit counters and codecs you can see) if available

[MatrixS2000]

Originally Posted by MOONPHASE

read this article and you will know


http://www.highdefdigest.com/news/sh...ess_Audio/1233

Some parts of that are very misleading...a 0 does not always represent silence - he shows that all 0s can be dropped - not true.

[MatrixS2000]

Originally Posted by Brain Sturgeon

Does resampling to a higher bitrate from an identical master add anything?

If the 16bit master didn't have it, neither will the 24bit re-master. You could have algorithms that could try and predict what may have been there had the master been 24bit, but it's just guessing...

my choices are

1) highest bit/frequency
2) if the same pick PCM over DTHD

+2

[view-it-blu]

Why no option for DTS HD MA? That's my choice!

[MatrixS2000]

Originally Posted by MOONPHASE

read this article and you will know


http://www.highdefdigest.com/news/sh...ess_Audio/1233

That article is very misleading...a 0 does not represent silence and a 1 represent sound. Both are needed to reform the wave.