Dolby Digital Plus

My question is: Is Dolby Digital Plus an HD audio format? What's the difference between that and Dolby TrueHD, DTS-HD, and PCM Uncompressed? Or are they all on the same level?

Dolby TrueHD, DTS-HD Master Audio, and uncompressed PCM are lossless audio codecs. That is, all three are highest-definition audio formats, supposedly taking exactly what is in the original soundtrack and transferring it to disc and to your speakers with nothing lost in the translation. Dolby Digital Plus, regular Dolby Digital, regular DTS, and regular PCM are all lossy in one way or another (depending on the bit rate used) and lose a little something compared to the original soundtracks (generally heard as softer definition, less dynamic range, less impact, less tautness, etc.).

The situation in the lossy formats is complicated further, however, by the bit rates used. Some reviewer friends of mine report that they don't think there is much difference between a high-bit-rate DD+ track and a TrueHD track. The problem is that you won't usually find these two tracks on the same disc for comparison. For example, discs with TrueHD tracks usually come paired up with low-bit-rate DD+ tracks (to save disc space), making comparisons rather one-sided. Note that the award for best audio this last year (from whatever organization, I can't remember) went to "Transformers," which has a "lossy" Dolby Digital Plus soundtrack. But the DD+ was done up at such a high bit rate, it probably didn't lose much in impact, bass, frequency range, or clarity compared to what the studio could have done with THD or uncompressed PCM.

Nothing in life is easy.

John

[Post edited by John J. Puccio on Feb 4, 2008]

John the only tracks that would be comparable would be the UK version of Bourne Ultimatum which has a high bitrate DD+ track and the US version which has Dolby True HD. However I'm not spending the money to import it just for comparison purposes.

Since I've gotten the ONKYO 605. I've listen to DTHD and LPCM on the same disc and there is a difference. The DTHD track averages between 2.5 and 3.5 Mbps and at times it peaks at 4.6, but LPCM stays at 4.6 Mbps thru out the movie. To my ears the LPCM track sounds more richer than the DTHD track. I would love to here a dts HDMA track but since the PS3 does not support dts HDMA yet I guess I'll have to wait for an update. Oh and by the way I'm no expert.

The only issue with comparing LPCM to Dolby TrueHD is Dolby uses a weird algorithim to enhance dialog which LPCM does not. Which can effect how the track sounds.

Here are some good articles about the newer audio codecs the first one deals with LPCM vs TrueHD

http://www.highdefdigest.com/news/show/1233

This one deals with all the HD codecs.

http://www.highdefdigest.com/news/show/1064

[Post edited by Movielover316 on Feb 3, 2008]