Why PCM should be the future of Blu-ray audio, not TrueHD/DTS-HDMA

[mov9384ie]

Bitrate math:

The studio soundtrack for majority of movies is mastered at 5.1 24/48 (There are arguments that 24bits is wasteful for consumers and only studios need it to avoid rounding errors, but we'll forego that debate and just use 24bits). TrueHD & DTS-HDMA are considered to have similar specs

PCM
2 hours @ 5.1 24/48 LPCM = 6.21 Gbytes @ 6.9 Mbps

Dolby TrueHD
2 hours @ 5.1 24/48 TrueHD = 3.06 Gbytes @ 3.4 Mbps ABR with 5+ Mbps peaks


Now there are two main things to consider: capacity and bandwidth. For capacity you'll save 3 Gbytes and for bandwidth you'll save 2 Mbps. Are these savings necessary?

Look at this list of blu-ray movie bitrates: https://forum.blu-ray.com/showthread.php?t=3338

Ignore mpeg2 or bd25 movies because those are old non-factors. Ignore movies that waste space (2 video encodes for pip, 2 lossless tracks). Then find movies that wouldn't have 3 Gbytes to spare for pcm. You'll quickly find that capacity is not an issue.

As for bandwidth we do not know peak rates from the list. But there are movies that have excellent video quality while having 2 lossless tracks such as spiderman3. If spiderman3 can afford to have pcm and truehd simultaneously, then we know bandwidth for video bitrate peaks is not an issue.

So given that blu-ray is built to handle pcm audio and that pcm support is MANDATORY and exists on all players, why do people want dts-hdma players so much? I would rather see people demand that Fox start using pcm so that EVERYONE can enjoy lossless audio NOW without having to upgrade to new players or pray for firmware updates.

Audio compression, even lossless compression, seems archaic and only necessary for hd-dvd.


EDIT:
People seem to be arguing that "in the future" saving 3 gbytes on a 50 gbyte disc will matter:
1) That's unrealistic. If you bother to look at the blu-ray bitrate list you'll see that 50 gbytes can provide excellent, tier 0, video quality with lossless audio and still have space for extras.
2) The problem of saving 3 gbytes more would only matter if the goal is to fit everything on 1 disc. Would you rather get an extra 3 gbytes of content on a 1 disc release or extra 50 gbytes of content on a 2 disc release?
3) A movie which has so much content that it begins to approach the 50 gbyte mark is likely to be released as 2 disc set


Compression is a compromise made because limitations don't allow delivery of the original uncompressed product, in this case PCM (even with lossless compression you are making a compromise with money: decoding an optional codec adds hardware costs and licensing fees to the player). PCM isn't some old backwards technology that some people are trying to portray it as, PCM is the ultimate goal of what studios are trying to deliver to you.

[BStecke]

I agree . . . if DTS HDMA wasn't the headache it is I think it'd be the best overall format, but with what we've got now, I love seing PCM soundtracks.

[quetzalcoatl]

Say what you wish but when every movie I own that has both a TrueHD and PCM track on it the TrueHD sounds better.

And I am one that buys Fox titles just because they have DTS HD MA on them. And if that stopped I would stop buying titles.

Where in theory all three should sound the same but they donot not. And I think the exact opposite of you. PCM is the older tech and as such needs to be ditched in favor of the newer ones. Just because of the fact that Blu-ray is cutting edge. But I am willing to say put a PCM track on there as long as one of the others is there as well. But donot take away the other two just because some are not willing to upgrade.

[NutsAboutPS3]

I would personally like to see TrueHD included for people who want to use "night mode" on their amps to avoid deafening the neighbours. This is actually a major problem for me with discs that only have DTS HD MA and I find my viewing experience spoiled by having to constantly turn the volume up and down while watching the movie, not to mention that I can't do it fast enough and many loud sounds still get through. I have even resorted to setting the volume to a level that makes the loudest sounds an acceptable volume, then turning on subtitles to be able to tell what people are saying, because the dialog is too quiet, but obviously that also spoils the movie to some extent.

[HDJK]

Originally Posted by quetzalcoatl

Say what you wish but when every movie I own that has both a TrueHD and PCM track on it the TrueHD sounds better.

And I am one that buys Fox titles just because they have DTS HD MA on them. And if that stopped I would stop buying titles.

Where in theory all three should sound the same but they donot not. And I think the exact opposite of you. PCM is the older tech and as such needs to be ditched in favor of the newer ones. Just because of the fact that Blu-ray is cutting edge. But I am willing to say put a PCM track on there as long as one of the others is there as well. But donot take away the other two just because some are not willing to upgrade.

Never mind the fact that a TrueHD/DTS HD MA track both end up as 'old' PCM... If you did hear an improvement, it's probably due to a higher bitdepth on the TrueHD track (as on Ghost Rider for example).

[quetzalcoatl]

Originally Posted by HDJK

Never mind the fact that a TrueHD/DTS HD MA track both end up as 'old' PCM...

True but I am not the only one that is hearing a difference. It is across every make of player that can bitstream the audio and every receiver that can decode it. So there must be something to it.

[musicman1999]

Originally Posted by mov9384ie

Bitrate math:

The studio soundtrack for majority of movies is mastered at 5.1 24/48 (There are arguments that 24bits is wasteful for consumers and only studios need it to avoid rounding errors, but we'll forego that debate and just use 24bits). TrueHD & DTS-HDMA are considered to have similar specs

PCM
2 hours @ 5.1 24/48 LPCM = 6.21 Gbytes @ 6.9 Mbps

Dolby TrueHD
2 hours @ 5.1 24/48 TrueHD = 3.06 Gbytes @ 3.4 Mbps ABR with 5+ Mbps peaks


Now there are two main things to consider: capacity and bandwidth. For capacity you'll save 3 Gbytes and for bandwidth you'll save 2 Mbps. Are these savings necessary?

Look at this list of blu-ray movie bitrates: https://forum.blu-ray.com/showthread.php?t=3338

Ignore mpeg2 or bd25 movies because those are old non-factors. Ignore movies that waste space (2 video encodes for pip, 2 lossless tracks). Then find movies that wouldn't have 3 Gbytes to spare for pcm. You'll quickly find that capacity is not an issue.

As for bandwidth we do not know peak rates from the list. But there are movies that have excellent video quality while having 2 lossless tracks such as spiderman3. If spiderman3 can afford to have pcm and truehd simultaneously, then we know bandwidth for video bitrate peaks is not an issue.

So given that blu-ray is built to handle pcm audio and that pcm support it MANDATORY and exists on all players, why do people want dts-hdma players so much? I would rather see people demand that Fox start using pcm so that EVERYONE can enjoy lossless audio NOW without having to upgrade to new players or pray for firmware updates.

Audio compression, even lossless compression, seems archaic and only necessary for hd-dvd.

Agreed, I think people hear a difference because they think there should be one.The only difference could be 24/48 or 24/96 and i don't believe that most peoples systems can resolve that difference.

bill

[The Guardian]

P.S. I think Fox is under contract with DTS so they have to use DTS HD MA.

[WickyWoo]

and so is New Line now

[jsteinhauer]

I would assume that some notice a difference, because different hardware is processing the sound. Not all of course. But not all decoders and post-processors/mixers will necessarily yield the same results. I make this assumption based on the basic schematics that DTS has on its website regarding how the HD sound is decoded with respect to your hardware setup.

Furthermore, you also can't assume that the decoder in your hardware operates error-free, and you also can't assume that the PCM signal gets passed from your player to your receiver error-free. There are so many variables to consider that might make one sound better than another.

[JTK]

Good.

What else do you need besides LPCM? You can't do any better than that IMO.

[WickyWoo]

Remove as much processing from the chain as humanly possible

[HDJK]

Originally Posted by WickyWoo

Remove as much processing from the chain as humanly possible

Amen.

[DaViD Boulet]

Guys,

as Blu-ray supporters we should be *forward* thinking, and not stick to ideas that favor first-generation (obsolete/inferior) hardware.

DTS-HD MA decoding will be standard in players and new receivers probably in a year. TrueHD is already common in most BD players.

Let's just relax and not expect early BD hardware to be the end-all and be-all. You'll be upgrading to a profile 1.1 player at some point. It will either decode advanced audio streams interally or stream them over HDMI 1.3 to your recevier.

*** software should always be mastered in the most forward-thinking way possible ***

Remember how some studios (Criterion) actually argued against 16x9 anamorhpic DVDs because "most players" on the market did a bad job of 4x3 downconversion for 4x3 viewers? Pretty short-sightes wasn't it... especially since that Criterion DVD of Brazil you paid $$ for is probably still on your shelf in crappy 4x3 lbx.

Now, PCM is full quality, so in that sense it's not a compromise. But if the extra space savings of TrueHD and DTS-HD MA allow for an additional language or special feature, or increased bit-depth (24 instead of 16), then let's be thankful that the studios are forward-thinking on this. Your next-gen hardware will take full advantage and your library of software will be better-mastered because of it.

[DaViD Boulet]

Agreed, I think people hear a difference because they think there should be one.The only difference could be 24/48 or 24/96 and i don't believe that most peoples systems can resolve that difference.

Listen to the David Matthews Band BD (my review at dvdfile.com should be up Weds or Fri). The 96 kHz (on the Dolby TrueHD) really changes the soundstage presentation in an incredible. way. I wish *all* PCM-based digital audio was 96 kHz.

[jdsanko]

I would own a stand alone BD player today if all BD's had PCM soundtracks. I don't want to buy a new receiver. I enjoy the sound of my Yamana 795a very much. It also runs very cool under heavy loads, which means it is not working very hard and is well desingned. It also fits nicely on the 16 inch deep sheleves were I keep my gear.

DTA-MA is a real pain the the my behind. No player can decode it and send it out the analog outs that I am aware off. Only a few can bitstream it over HDMI which is of no use to me.

I won't buy a player that can not decode a and send all codecs analog.

[dobyblue]

Fox gives people without multi-channel ouputs or HDMI receivers the best audio possible through optical.

I have no problem with their support of dts-HD Master Audio.

[jdsanko]

I would own a stand alone BD player today if all BD's had PCM soundtracks. I don't want to buy a new receiver. I enjoy the sound of my Yamaha 795a very much. It also runs very cool under heavy loads, which means it is not working very hard and is well desingned. It also fits nicely on the 16 inch deep shelves were I keep my gear.

DTA-MA is a real pain the the my behind. No player can decode it and send it out the analog outs that I am aware off. Only a few can bitstream it over HDMI which is of no use to me.

I won't buy a player that can not decode a and send all codecs analog.

[ClaytonMG]

I hear a difference between TrueHD and PCM... TrueHD is notably weaker on titles like 300 (even once you've level matched). PCM was more powerful and more open sounding. But that's just on WB titles due to them using 16-bit tracks along with DialNorm. On Sony's titles, I do think the TrueHD does have a slight edge over the PCM, but only a very slight edge.

[dialog_gvf]

Originally Posted by DaViD Boulet

Now, PCM is full quality, so in that sense it's not a compromise. But if the extra space savings of TrueHD and DTS-HD MA allow for an additional language or special feature, or increased bit-depth (24 instead of 16), then let's be thankful that the studios are forward-thinking on this. Your next-gen hardware will take full advantage and your library of software will be better-mastered because of it.

I agree. There is no reason to shoot down lossless codec use. It can allow multiple lossless, or a heck of a lot extra DD 5.1 streams on the disc, so it improves the product for the worldwide audience, and allows better economies of scale because a single disc production run can serve the world.

PCM or lossless, it's all good. I'm just happy PCM can ALWAYS be offered. It's the source data for all the other encodings, and costs nothing to put it on the disc.

Gary