What is Dolby TrueHD?

[Cristofori]

Hello all,

What exactly is this Dolby TrueHD that I see on newer HT receivers?

Am I to understand that the audio on movies now have been elevated closer to the levels of HD Video? Is it similar to, or superior than SACD or DVD-A?

If so, when can I expect to see regular musical recordings released in TrueHD? If not why not?

Or is this all just more of the same old useless hype and marketing gimmicks from the usual suspects? If we now have "TrueHD", then what did we have before?

I've never been a fan of Dolby anything as far as music is concerned, but I'm still eagerly waiting for somebody to come along and pick up where SACD/DVD-A left off!

 

[dkane360]

http://en.wikipedia.org/wiki/Dolby_TrueHD

If you want to hear a great example of Dolby TrueHD, this is a good start:
http://www.amazon.com/Chris-Botti-Boston-Blu-ray/dp/B001R60ESE

I can't comment on the quality vs SACD and DVD-A though. But TrueHD is lossless so it should be as good as it gets, although it still depends on how its recorded and mastered.

 

[s162216]

Your getting two completely different things confused.

SACD and DVD-A are physical mediums for music that operate on uncompressed digital sound such as PCM with a high sample rate of 96khz.

TrueHd is a lossless compression format (i.e no part of the sound is lost supposedly) for films being sold on bluray/hddvd that takes the raw audio and compresses it with a higher bitrate and sample rate than normal Dolby Digital which has to be used on DVDs. These sound better because of the higher bitrate and sample rate.
The reciever decodes the TrueHD bitstream to be played as normal audio.

These would likely sound exactly the same but they are not at all the same if you get what I mean. If there is any minute difference the TrueHd would always lose as it is compressed whilst SACD and DVD-A are just the audio directly as it was recorded with PCM or whatever.

 

[JerryLove]

SACD and DVD-A are physical mediums for music that operate on uncompressed digital sound such as PCM with a high sample rate of 96khz.

They are far more than just physical mediums. DVD-A is physically the same as DVD (I believe SACD is as well).

TrueHd is a lossless compression format (i.e no part of the sound is lost supposedly)

"Lossless" has a very specific definition. The bits coming out of a TrueHD decompression are exactly identical to the ones that went in. If they are not, then Dolby is actionable for fraud.

These would likely sound exactly the same but they are not at all the same if you get what I mean. If there is any minute difference the TrueHd would always lose as it is compressed whilst SACD and DVD-A are just the audio directly as it was recorded with PCM or whatever.

Lossless compression is entirely irrellevent to sound quality. It has no effect what-so-ever.

 

[AcuDefTechGuy]

Dolby TrueHD and DTS-HD MA are prerequisites of Audioholics Membership.

Please confirm that you are IN FACT bitstreaming these Audio Codecs before proceeding any further.

j/k.

 

[JerryLove]

j/k.

I don't think you are

 

[GlocksRock]

TrueHD is the next best thing to DTS-HD Master Audio

 

[MDS]

If there is any minute difference the TrueHd would always lose as it is compressed whilst SACD and DVD-A are just the audio directly as it was recorded with PCM or whatever.

This is a common misconception about 'lossless' compression. Lossless compression reduces the size of the file by reducing the number of bits needed to represent the audio. It is conceptually the same as zipping a bunch of files into one archive, although the algorithms and file formats are much different. If you were to just 'zip' a PCM track, it will not be reduced in size much at all.

Nothing is lost and upon 'decoding', you get back exactly what you started with - the original uncompressed master track. It is unlike 'lossy' compression algorithms (MP3, AAC, et al) which reduce the file size by actually removing parts of the audio that their perceptual model thinks the ear would not hear anyway.


DVD-A is also compressed. It uses an algorithm known as Meridian Lossless Packing (MLP) and also must be 'decoded' to get back the original master track.

All of these different lossless compression techniques are slightly different (different algorithms and file formats) but the results are the same. Any difference in sound, if at all, will be due to the original recording and mastering and not the algorithm used to make it take up less space on a disc.

 

[Cristofori]

http://en.wikipedia.org/wiki/Dolby_TrueHD

If you want to hear a great example of Dolby TrueHD, this is a good start:
http://www.amazon.com/Chris-Botti-Boston-Blu-ray/dp/B001R60ESE

I can't comment on the quality vs SACD and DVD-A though. But TrueHD is lossless so it should be as good as it gets, although it still depends on how its recorded and mastered.

So basically, this really isn't a format so to speak and would only work with Blueray films?

Should I not expect any music only Blueray discs in the future, and if there were, would the TrueHD be better than regular CD audio, assuming you are only listening in two channel mode?

 

[Seth=L]

So basically, this really isn't a format so to speak and would only work with Blueray films?

Should I not expect any music only Blueray discs in the future, and if there were, would the TrueHD be better than regular CD audio, assuming you are only listening in two channel mode?

Dolby TrueHD has a higher bitrate and sampling rate. A CD uses 16 bit audio at 44.1khz for 2 channels, where Dolby TrueHD can use up to 24 bit audio at 192khz for 2 channels. Dolby TrueHD is a derivitive of MLP Lossless, the same codec used for DVD-Audio, an audio only format owned by Toshiba Corp. meant to compete with Sony's SACD format. Dolby TrueHD adds more channels and a higher sampling rate to original DVD-Audio making it a more robust format.

For now Dolby TrueHD is only being seen on Blu-ray discs (it was mandatory on HD DVD) but we may begin to see it in music only discs, as more DVD players and other sources are taking the HDMI route it's not outside the realm of possibility. How viable would such a format be though? SACD and DVD-Audio fell through the cracks, I don't believe an another audio only format is going to be of interest to the average consumer and the average consumer makes up the customer base. There have been a few releases of live performances and unplugged performances that offer excellent audio and picture quality through the use of the Blu-ray and the audio codecs available on Blu-ray such as Dolby TrueHD and competing format DTS-HD Master Audio. If the Japanese had their way I'm sure neither format would exist, neither company is all to dissimilar from THX in the regard they don't seem to do much authoring and more so just taking licensing fees for the use of their compression codecs. multichannel PCM can do the same job, or Sony's SDDS could have been used and evolved into a current audio format that would make sense with today's current home theaters. DTS and Dolby are both american companies, and I don't think either is really needed.

 

[Seth=L]

TrueHD is the next best thing to DTS-HD Master Audio

The only difference is that DTS-HD MA has a variable bit rate cap of 24.5mbps and Dolby TrueHD's bit rate cap is 18mbps. You would be hard pressed to notice a difference, both offer a massive data stream that far exceeds necessity for 8 channels of audio.

 

[s162216]

The only difference is that DTS-HD MA has a variable bit rate cap of 24.5mbps and Dolby TrueHD's bit rate cap is 18mbps. You would be hard pressed to notice a difference, both offer a massive data stream that far exceeds necessity for 8 channels of audio.

Thats because TrueHd and I think DTS-HD MA can have up to 14.1 audio but the Bluray specification limits it to 8 channels at the moment.