What is the difference between L-PCM 5.1 audio and DTS-HD MA 5.1?

[bergqvistjl]

Hi, looking at the detail of the audio tracks for the Led Zep Celebration Day blu ray audio only release, I see they have 2 surround sound tracks:

L-PCM 5.1 @ 48kHz/24bit
DTS-HD Master Audio™ @ 48kHz/24bit

If they both have the same sample rate and bitrate, what is the difference between the two? and which is of the higher audio quality in terms of the 1s and 0s? What are the advantages/disadvantages? (I'm a total n00b in this aspect pretty much)

[HAMP]

Originally Posted by bergqvistjl

Hi, looking at the detail of the audio tracks for the Led Zep Celebration Day blu ray audio only release, I see they have 2 surround sound tracks:

L-PCM 5.1 @ 48kHz/24bit
DTS-HD Master Audio™ @ 48kHz/24bit

If they both have the same sample rate and bitrate, what is the difference between the two? and which is of the higher audio quality in terms of the 1s and 0s? What are the advantages/disadvantages? (I'm a total n00b in this aspect pretty much)

As far as the 1's and 0's, both tracks are the same. I believe they are giving the option between those two, because not all sources decode DTS-HD Master Audio.

[DavePS3]

If you go to DTS' website, they go into the numbers and even if you're downconverting the DTS-HD signal to regular DTS through Toslink or Coax (on an older receiver), there is a difference in the sound quality between that and the regular DTS track. I notice it. It's not quite as clear and detailed as the HD track but still better than the slifgtly older regular DTS. If you're able to run both, try them and see if you notice anything different.

[rpatt]

They are both loss-less. The DTS-HD MA is compressed and the L-PCM is not and takes up more space on the disc.

[Tech-UK]

No difference in sound, but the space saving and features provided by DTS-HD MA is the advantage.

@ Dave, The DTS core is only available if your sending audio via S/PDIF. Limited to 5.1 maximum dedicated channels, 48KHz @ 24-bit, giving a bit rate of 1.509Mbps. you do benefit in terms of channels but if you were to play the LPCM track you would get 2.0 and whatever the Sampling rate and bit depth is encoded (I believe still limited to 48kHz, 24-bit) resulting in 2.304Mbps (2 channel, 48kHz @ 24-bit) dedicated to 2 channels whereas the 1.5Mbps bit rate of the DTS track is occupied by all 6 channels, thus compressed lossy (i.e. you loose information).

[BIslander]

PCM is the original soundtrack. PCM is the digital format used throughout the entertainment industry. That's how movie soundtracks are recorded. CDs, too. Receivers, pre-pros, disc players, DACs, and nearly all of the audio equipment we use is designed to process PCM and convert into analog signals that drive speakers.

So, why do we have codecs such as DD 5.1, DTS, TrueHD, and dts-MA? Just one reason - to save space. PCM takes up a lot of space, so much space that a 5.1 PCM soundtrack cannot fit on a film or DVD. Dolby and DTS developed data compression codecs that work pretty much like zip files in order to squeeze large PCM tracks into smaller packages. You can't "play" a DD 5.1 or dts-MA track anymore than you can read a document that has been zipped up. You have to decode the track first, turning it back into PCM, so that your audio system can process it to produce sound.

TrueHD and dts-MA are lossless codecs, meaning the decoded output is identical to the input. You feed the original PCM track into the encoder, which compresses it to save space. Your playback system decodes (decompresses) it back into PCM, restoring everything that was taken out so that it is bit for bit identical to the original.

Bottom line: there is no quality difference between the 5.1 PCM track and the losslessly compressed dts-MA version. It's rare to find discs that offer both these days since nearly all players and AVRs can decode the lossless tracks.

[frogmort]

LPCM is the actual audio. DTS-HD MA and Dolby TrueHD are compression codecs that can losslessly compress and decompress the original LPCM audio, while saving space on the disc for better video quality and/or more bonus features.

Linear Pulse-Code Modulation

[AmishParadise]

The PCM track to my ears is more enveloping and natural sounding which shouldn't be taken as a knock to DTS-HD MA or DTHD which both sound fantastic as well. The DTS-HD MA and DTHD tracks just sound a tad bit more directional, at least with my room and setup. When sound pans for instance from front to back and so forth, the transitions with the PCM track sound more seemless to me. At the same time, if I had only ever heard a DTS-HD MA or DTHD track I'd never be wanting for more I don't think.

[BIslander]

Originally Posted by cds1834

The PCM track to my ears is more enveloping and natural sounding which shouldn't be taken as a knock to DTS-HD MA or DTHD which both sound fantastic as well. The DTS-HD MA and DTHD tracks just sound a tad bit more directional, at least with my room and setup. When sound pans for instance from front to back and so forth, the transitions with the PCM track sound more seemless to me. At the same time, if I had only ever heard a DTS-HD MA or DTHD track I'd never be wanting for more I don't think.

Sorry, but that is only possible if the soundtrack fed into the encoder is different than the PCM placed on the disc. Once again, dts-MA and TrueHD are simply data compression codecs, just like zip files. They can no more change the mix than a zip file can change the sentence structure or font of a Word document.

How have you done the comparisons? Are you listening to the same soundtrack using PCM and a lossless codec? If so, which movies, since there are precious few where the same track is available both ways. If you are comparing different films, then you are actually comparing different mixes, not encoding techniques.

[AmishParadise]

Originally Posted by BIslander

Sorry, but that is only possible if the soundtrack fed into the encoder is different than the PCM placed on the disc. Once again, dts-MA and TrueHD are simply data compression codecs, just like zip files. They can no more change the mix than a zip file can change the sentence structure or font of a Word document.

How have you done the comparisons? Are you listening to the same soundtrack using PCM and a lossless codec? If so, which movies, since there are precious few where the same track is available both ways. If you are comparing different films, then you are actually comparing different mixes, not encoding techniques.

Thanks for the feedback! Much appreciated. You are right on the money. I was comparing the PCM 5.1 track on a given disc to the old school DD 5.1 track, so obviously the PCM track would sound more enveloping and natural. Looks like Spider-Man 3 is the only title in my collection that offers both PCM and DTHD 5.1. Every other title in my collection that offers PCM only includes DD 5.1.

[NeoMaximuz]

I could be wrong, but I believe the PCM track on Celebration Day is 2.0, while the DTS-HD MA track is 5.1. There's your major difference.

But like I said, I haven't bought this yet, so I could be wrong.

[Arg]

Originally Posted by NeoMaximuz

I could be wrong, but I believe the PCM track on Celebration Day is 2.0, while the DTS-HD MA track is 5.1.

BD-Audio disc includes PCM 2.0 and PCM 5.1, and DTS-MA 5.1.

[HugoDarien]

hi what about dvd how many channels do they have in dts

ps. i want to talk more in details about the difference betwen dvd and bluray dts, dolby etc but i dont find a thread in this forum and as a new member i can not make a new thread

[BIslander]

DTS Surround and DD 5.1 are limited to six channels on DVD. (DTS-ES Discrete actually supports a 7th center surround channel, but that was rarely used.)

[hogger129]

Originally Posted by bergqvistjl

Hi, looking at the detail of the audio tracks for the Led Zep Celebration Day blu ray audio only release, I see they have 2 surround sound tracks:

L-PCM 5.1 @ 48kHz/24bit
DTS-HD Master Audio™ @ 48kHz/24bit

If they both have the same sample rate and bitrate, what is the difference between the two? and which is of the higher audio quality in terms of the 1s and 0s? What are the advantages/disadvantages? (I'm a total n00b in this aspect pretty much)

The difference is DTS-HD Master Audio is a lossless compression codec. It retains all the same information as the original source, but stores it in a way that takes less space than raw PCM. Upon playback, it is bit-identical to PCM.

The L-PCM one is just raw PCM. It's the full uncompressed sound. The advantage is compatibility. The disadvantage is that it takes up a HUGE amount of space.

I'm surprised that support for FLAC was never written into the Blu-ray spec or HDMI spec. FLAC often achieves better compression than any of Dolby or DTS's lossless codecs. I've even read about times when it compresses better than lossy DTS 5.1.