Video Asylum

Posted by Joe Murphy Jr (A) on January 09, 2007 at 23:32:24

In Reply to: some further questions please, posted by jeromelang on January 9, 2007 at 20:54:29:

if i understand you correctly... dts-hd and dd truehd has no sonic advantages over lpcm, just that they will be more efficiently packed onto the disc media, taking up less space.

Yes.

most lpcm soundtracks released so far are derived not from original 20/48 or 24/48 studio masters, but from a lower rez 16/48 version.

No, they are derived from the masters. However, they are converted to 16-bit from the 20-bit or 24-bit originals.

where do you get this information from? Is there a website detailing this, or are any BD players or av receivers about to display the information on the bitstream?

Simple math proves this to be the case. Here's a hint: the PS3 can display the audio codec, the number of channels, the audio bitrate, the audio sampling rate, the video codec and the video bitrate.

why the hell studios are doing this? are they afraid that the first few releases might be copied and pirated?

You'll have to ask them. It's probably due to the fact that 20/48 or 24/48 uncompressed LPCM combined with MPEG2 doesn't leave much room for other items they want to put in the data stream. Regardless of whether you are accessing these items/features or not while the movie is playing, they all take up bandwidth in the data stream (ie, they all run parallel in the stream) and storage space on the disc.

how will lossless at 24/48 or 20/48 compare to dts 96/24?

I haven't heard DTS 96/24 (I really hate the 96/24 designation, as it should be 24/96); however, lossless 24/48 should sound "fuller". By how much will be dependent on the listener and the system it's played back on. Also consider the resolution and sampling rates that today's soundtracks are mastered to: 20/48 or 24/48. If it wasn't mastered at 24/96, then DTS 96/24 doesn't get you anything.

were there ever any movie soundtrack orginal recorded and mixed at 24/96?

I have read that a few masters (less than 5?) were 24/96. I have no idea what movies these were for.

How are we ever to find out whether dts-hd and dd truehd is truely as "lossless" as they claim?

They are lossless. Believe it or not.

have you actually heard lpcm compare to current dts/dd? How would you dscribe the sonic differences?

Dolby Digital on DVD is adequate for dialog (not music or dynamic films). DTS at half bitrate is better and full bitrate DTS on DVD is very good. Still, they are not the equal to LPCM on a nice system. The new lossless codecs are the equal to LPCM as long as they are encoded at the same bit depth and sampling rate. Warner Bros uses Dolby TrueHD on a few releases, although they're at 16/48 despite the fact that the masters are 20/48 or 24/48. Note that they're still lossless soundtracks, but not the equal to the 20/48 or 24/48 LPCM masters. Kick-ass FOX, on the other hand, is encoding their movies in DTS-HD Master Audio at 24/48 and these are equal to their masters.

Can you suggest some movie titles that will showoff the advantages of lpcm soundtracks?

If you want to hear how 24/96 LPCM sounds in comparison to Dolby Digital, pick up an AIX Recordings DVD-A and play it in a DVD-A player. Compare the MLP track (5.1 lossless) to the Dolby Digital track (5.1 lossy).