Axiom Home Page Forums General Discussion Home Theater Dolby TrueHD and DTS Master HD question

I just got a brand new Samsung 3600 BD player, along with a brand new 55" Samsung LED 7100. The picture is simply awesome! I don't notice any difference in sound though, considering that 3600 has Dolby TruHD and DTS Master Audio HD capabilities. I have an Onkyo 804 receiver capable of HDMI 1.1. and have set it "direct" for pass through. How do I set my new BD player (Samsung 3600) to decode these new HD formats? Actually, the better question would be: would I be able to experience these new formats with my current setup? Any help would be greatly appreciated.

The truth is, there is little audible difference between a well encoded lossy DVD track and the new lossless BD tracks. Only in a direct comparison will most people be able to notice anything. So don't go expecting to hear the same big change as you can see going from 480i to 1080p.

That said, the player (which I'm not familiar with its exact settings) should have an option for LPCM output. Since they Onkyo is only HDMI 1.1 it probably can't decode the lossless formats itself, so "bitsteam" shouldn't be used.

Hey Thyname,
Congrats on your new purchase.

I looked up TX-SR804 on the web and it seems that the receiver does not have decoders for Dolby True HD or DTC HD Master. Which means you will have to use the audio decoders your BD player has. Personally, I prefer setting the player to bitstream the audio signal and let me receiver do the decoding.

In your BD player menu, you should have the option to turn these decoders on (in audio settings or somewhere. The options maybe 'bitstream' or 'PCM', you will have to choose PCM). You should be able to experience HD sound with your setup, its just that your receiver will not show Dolby HD or DTS HD Master on its display, instead it will say PCM.

Hope this helps.

Thank you both of you for the reply. It is relieving to learn that I will not need to upgrade my receiver to a HDMI 1.3 capable one.

I had already set my BD player to PCM. I am not sure how to set the receiver (Onkyo 804) when the player is on. Direct? Pure Audio? or some type of Dolby ProLogic? In any case, PCM shows in my receiver display. I assume I am listening to Dolby TrueHD and DTS Master HD Master.

Check to see if there is an "audio" button or something similar available on the remote of your BD player which will let you display and/or change the audio soundtrack on the t.v that is playing currently.

It's been a while (i think) since you posted, I tried getting in touch with you for an audition....you missed out on some big bucks there thyname

I'm not sure about your Onkyo, but I use the "External Input" setting on my Denon.

Are you referring to Ext. In? If so that deals with the multi-channel analog connection.

Yes, it has been a very long time since I was here last. This is a very expensive hobby and I have tried unsuccessfully to keep my self distanced. Why didn't you emailed me instead?

Did you get Axioms?

Skerdi, long time no see. Yes, the PCM indication on your receiver is correct. Since the player is decoding the True HD or Master HD to PCM, the receiver has no way of knowing how it originally started out before being decoded. You're getting whatever audio quality may or may not be present in the Blu-ray. As Chris mentioned, the audio difference between the loss-less formats and the improved lossy DD and DTS content has been shown in blind testing to be nearly indistinguishable, so don't expect to hear a significant difference unless the particular disc wasn't processed equally well.

I always check in the player to see if the lossless soundstrack True HD or DTS Master is actually being played. There have been a few movies such as Batman Begins and The Dark Night and maybe a few others in which the regular DD 5.1 soundtrack is default and you have to switch to the lossless each time.

There should be an option for PCM in your presets (buried in the Onkyo menus). You can choose this for straight, non 'messed with' sound from your new BD player. Or, you can choose any of the DSP's (Dolby PLII, THX whatever, etc.).

Hi John, good to see that you are still around here. I used to always read and enjoy your posts. Thank you for the reply.

In all fairness John, I recall reading results of a blind listening test or two where the listeners could tell a difference, and the nod was given to the high rez tracks.

I know that in my set up, I can tell whenever the BR disk is playing the standard sound track. When I switch over to the high res track, the difference is beyond doubt. Enough so that I can’t help but wonder what folks are smoking when they make claims to the contrary.

Now all that being said, I have numerous BR disks with downright horrible High Rez sound tracks. Just because the BR has DD-HD or DST-HD on the cover, that does not guaranty high quality audio.

Hi there!

I remember you buying a Marantz receiver capable of 1.1 HDMI passthrough. Do you still have it or upgraded? If you still have it, are you still able to get the high rez formats by letting your BD player do the decoding? It appears that you can tell the difference between the "old" and new High rez formats.

I known I can hear the difference almost immediately, but like any audio differentiation I think it takes a certain amount of "training" of the ear. I doubt most people would notice a big difference initially, but after listening to great BD lossless tracks for a while and I'm sure they would begin to notice.

I think the primary differentiator is that it takes more work/skill to mix an outstanding lossy track than to mix a great sounding lossless track. In mixing both you need to be aware of spatial positioning and depth of the track, but with lossy tracks you need to also be very aware of dynamic range, compression artifacts, etc... all the standard issues linked with lossy compression. There's simply more to get right and consequently more that can go wrong.

I've heard both great lossy and lousy lossless mixes. But, I'm willing to bet that as a percentage per track type, there are more great sounding lossless mixes than lossy ones.

Lossless audio allows the sound engineer to focus on the soundscape and ambience, and forget about the technical challenges associated with lossy compression.

All that being said, I don't know why studios don't just go LPCM everywhere? Why even bother with DTS-HD MA or TrueHD? Same end results and with the storage capacity of BD it's not like space is an issue...

I find the dynamic range to be better overall as well as the clarity in dialogue. The surrounds seem "more alive" as well but it is less noticable. The biggest thing for me is the dynamic range.

I agree completely. I believe them to be clearer, with more detail in them.

Storage capacity is only part of the issue. The bigger factor is the maximum allowed bitrate of a BD is 36 megabit/sec. A 7.1, 48 kHz, 24-bit PCM track takes over 9 Mbps by itself. Adding multiple languages would quickly use up all the available bandwidth, leaving nothing for the video or subtitle tracks. Dolby's and DTS's lossless compression can easily achieve a 25% reduction, and routinely exceed 50%.

I agree especially with speakers like Axiom, they really benefit IMO. Gun shots I find sound soooooo good especially the final gunshot blast by the bank manager in The Dark Night , little details such as the shotgun shell hitting the floor sound so clear and deatailed, it feels like you are in the bank with the Joker . The whole first part of that movie is just incredible.

Agreed about the lossless... The clarity and detail is outstanding.

I don't think that would be an issue until ou get to >8 channel audio.

BD drives read at a 1x speed of 36 Mbps, but the BD spec allows for AV rates of up to 48 Mbps. Of that video can be a maximum of 40 Mbps. 8 channel LPCM audio at 16-bit/48khz only requires 6.144 Mbps. There's still the full 40 Mbps of available AV b/w for video.

Even at the 36 Mbps read rate it still leaves ~30 Mbps which is still more than enough to encode very high-quality HD level 1080 AVC or VC-1. In fact, The Dark Knight, with its outstanding video quality is encoded at an average rate of 24 Mbps. I haven't checked but I don't think it even peaks near 30 Mbps.

Also, multiple audio streams shouldn't affect this since you only play one stream at a time.

I agree that the lossless compression options give the disc producer a lot more headroom and freedom with the bandwidth, but from a practical perspective it doesn't seem to be a real problem today and an easy way to save on additional licensing fees during production.

A much better way to address this long term would be for players to read at greater than the 1x speed (36 mbps) so that they could fully utilize the full BD AV bandwidth of 48 mbps....

Multiple audio streams do have an effect, because they are multiplexed in together. The player has to read the container at the mux rate and then extract the parts which it currently needs, ignoring the rest. It's done this way so A/V sync is easy to maintain and there's no seeking required to pull the video from one location on the disc and the audio from another.

Also, no one is going to use less than 20 bits per sample for a feature presentation. With the way PCM is stored that still takes 3 bytes (24-bits). Compression (both lossy and lossless) can pack multiple samples together to recover the wasted 4 bits.

The 48 Mbps allows for buffered data to burst above the 36 Mbps transfer rate of the drive. But the long term average bitrate can never exceed 36 Mbps without creating a new non-backward compatible format, as all the old players with the 1x drives couldn't play the disc correctly.

Individual discs can of course vary in the quality of audio processing given, and impressions gained in casual listening may differ from reality. Note again the results from controlled tests, blind and otherwise, in HomeEntertainment Magazine which have been cited here a couple times before.

Wow, DTS studio's don't sink nearly as much money into their audio playback equipment as Dolby does, that's forsure. I'm glad I read that article though, because I've been under the impression that the TrueHD and MasterAudio formats were both uncompressed. I didn't realize they were still compressed and then uncompressed without loosing an information. I guess I should have figured that when they call it 'lossless' technology.

But I wonder, if a BluRay disc already has an uncompressed PCM track on it, why would they also then try to squeeze either a TrueHD or MasterAudio track on it as well? Isn't that just a bit of overkill?

Most newly released BDs no longer use an uncompessed PCM track. It was mostly a stop-gap measure to allow lossless audio while Dolby and DTS were putting the finishing touches on their formats.

I don't know of any which used both PCM and another lossless. Heck, I don't know of any which use both competing lossless compression formats at the same time.

Superbad has both TrueHD and PCM. I'm sure there are others.

Ok I'm still confused... if they can put an uncompressed track on a BD then why even bother with TrueHD and MasterAudio at all? Space saving measure? It seems to me that the uncompressed track would be the best possible soundtrack to listen to, so TrueHD and MasterAudio, as good as they are, are a step backwards aren't they?

Not that any of us will ever be able to tell the difference, but I guess if I had my druthers I'd rather just have the uncompressed soundtrack and say screw the rest of the choices.

I have no opinion one way or the other on lossless versus uncompressed. I'd rather they utilize the compression if it allows for higher-quality video. If the format could handle 5 hours of uncompressed video and audio, I'd be all for that, but I wonder how noticeable the difference would actually be. The best stuff on Blu-ray looks and sounds amazing. To see any major improvements will take a new format, and on the audio side, how much better can it actually get?

Yeah Micah, THD and MHD take up about half the space in their compressed form as the uncompressed PCM does, so there's some space saved that can be used for other video or audio purposes.

You're still not fully grasping the fact that the uncompressed PCM and the two loss-less compressed formats give exactly the same result: a bit-for-bit identical reproduction of the master recording. So, none of the three is any better as a format, and it's up to the producers of the recording how good a job they do with whichever they choose to use.

Of course, there's been quite a bit of hype about what really isn't a very big deal and it should be remembered that we've had a format around for quite a while that has provided uncompressed audio: the CD.

Yeah and that's what I'm talking about. Although I understand that the end result is practically inaudible, the fact that it is compressed is to me not quite the 'ultimate'. IMO the uncompressed audio track is the absolute standard (it can be played at a higher bit rate, no?), and anything else is a step backward... it might be a 1 millionth of an inch of a step backward, but a step backward all the same. So what I'm wondering is, why did they stop where they did with the BluRay? Because it seems they left room for improvement. Which means somewhere down the road, whether it's 2 years, or 10 years or 20 years, they will come out with a new format and tout, "now you can listen to your movie soundtracks UNCOMPRESSED, along with full bandwith video"!!!

I don't see why they didn't just go ahead and do that now? It seems to me they stopped short of giving us everything we could ever want, just so they can upgrade it later. I'm sure they didn't have to stop where they did. They could have given the new disk 15, 20, 30% more volume to squeeze in everything it would take to give us the very best video along with uncompressed audio.

I'm quite sure that would have been possible. I guess we'll just have to wait for the next generation to come out.

No, you're still not grasping it. It isn't just "practically inaudible", it's exactly the same thing. Digital recordings(such as the CDs which we've had for almost 30 years)use the pulse code modulation(PCM)process. THD and MHD take the PCM bits and "squeeze" them into about half the space. Then when they're decoded("unsqueezed")what you have is exactly the same PCM bits that you got from the recording.

Additionally the lossless, compressed tracks can actually offer higher sampling rates than raw PCM, because there is a max-bitrate allowed for an audio track. At 192 kHz, 24-bit, with 6 channels (5.1; the sub-effects channel still has to be stored as full-range) PCM would exceed that, but TrueHD and DTS-HD MA with their compression can stay under the limit.

Think of it this way. What's better downloading a ZIP file of a document and unzipping it, or downloading the document straight? They are both the same in the end, because the ZIP file compression is lossless.

Ok I'm sorry, I thought it was the other way around. I thought the PCM was readable at a higher bit rate.

Mica, you may find this helpful with trying to grasp this stuff. I wrote it a while back when HD-DVD and BR was rolling out..... Some info is dated.

http://www.axiomaudio.com/boards/ubbthreads.php?ubb=showflat&Main=13094&Number=181379#Post181379

I tend to refer to lossless compressed sound like a Zip file.

We are all pretty familiar with Zip files. It is a way to take some files and compress them into a smaller space by removing unnecessary bits. You can often take a file and make it half as big as it was before.

When you unzip the file, it appears exactly the same as it was before. Your email, your word document, your family pictures, come out exactly the same as they were before you zipped them. If it was a lossy compression, you would lose parts of your emails and your kid's pictures would be without their face.

Lossless compression works the same way as zipping a file. PCM audio has a lot of unnecessary information that just takes up space but doesn't do anything. It is a pretty bad way to pack in your information. It is like letting your wife pack the van before a trip. She is probably terrible at it and fits it all in the van improperly and wastes space. When you go back in and pack the van yourself, you find all sorts of ways to pack the van with more efficiency to get more stuff in a smaller space. When you get to your destination, you didn't have to leave the dog behind because you couldn't fit it in the van.

So, there is no technical way that a lossless PCM track can sound any different than a lossless TrueHD or DTS Master soundtrack. The dog still has his nose and your email still says the same dumb gossip that it started with.

That said, even lossy compression sounds great to me. In a blind test with friends, not one of us could determine reliably what was lossy vs lossless. Could we determine a difference? Sure we could. Each had a slightly different sound. Most apparent was that each had a different volume level. But we couldn't determine which one was the lossless vs which one was the lossy. I don't bother myself with it. I will listen to whatever is the default track. I will even rip some disks to a player that can't pass HD audio and it makes no difference to me whether it is lossless or lossy.

On a side note, some of you also talk about video. I think it should be made clear that video is always compressed. A non-compressed hour of video takes something like 2TB. That is Terra Bytes. That is one of the largest harddrives available for each hour of video. A BD is most often compressed using the h.264 compression scheme which as you can see, results in a fantastic picture. it is pretty hard to find compression artifacts in many of the compressed h.264 video streams available today.

Ok, I'm starting to get it now. Thanks guys.

I'm quite sure in 10 years time we will have discs that are 100 percent uncompressed audio and video. I mean think back to the 80's and the Commodor 64... that was a 64 MEGA BYTE hard drive... a digital watch has more memory than that these days. Back then you wouldn't even fathom having an external hard drive that had two Terra Bytes worth of storage on it.

And at the rate of technology in 10 years time our cell phones will probably be able to pack 500 or so Terra Bytes in a mini-SD card. So by then we will have all the space available to put fully uncompressed video and soundtracks on one tiny disc. I wouldn't doubt it for a second.

Excellent explanation, autoboy. Especially the van part, although I see it when she packs the dishwasher. One minor quibble, with the family pictures. JPEG and GIF formats incorporate compression too. On a Mac in iPhoto (probably most other programs too) it asks what quality you want when you save it. Obviously higher quality = bigger files = less loss. You can tell when a GIF has too much loss - it gets blotchy. Interesting how the left brain stuff (music, pictures, video) tolerate loss and right brain stuff (words, numbers, programs) don't.

A Commodore 64 with a hard drive? I think I was in the wrong 80s!

Not to mention 64MB... that would have been outrageous then. It was 64K of memory.

Yeah? Well, at my age, it's all "old brain" stuff and, lemme tell you, that stuff is ALL lossy.