x-box HD-Drive and DTS
Posted by: john R1 on 24 May 2007
how is it since the latest upgrade for the hd-drive, you can now output dts 3-2-1 on hd discs that don't have a dts soundtrack, or am i missing something ?
Posted on: 24 May 2007 by Allan Probin
The Toshiba HD-DVD players have been doing this since their inception and it's a really neat way of allowing owners of 'legacy' surround decoders to (partially) access the high resolution/lossless audio tracks on HD-DVD.
I've not seen details of the Microsoft update but I'm sure it will be to enable the X-Box to downmix Dolby Digital Plus or Dolby True HD soundtracks to standard DTS at 1.5Mbs. Remember, normal Dolby Digital on a standard DVD is encoded at something like 448kbs and DTS something like 780kbs. So what the Xbox will be doing is taking the higher resolution/lossless audio from a HD-DVD and giving you something that is compatible with a standard surround decoder but of higher quality and bitrate than you would get from normal DVD. Prior to this update, the Xbox would have been doing the exact same thing but downmixing the high res audio to Dolby Digital at about 640kbs.
If you want access to the full quality of Dolby Digital Plus or Dolby TrueHD (lossless) then you will need a HD player that can output audio via multi-channel analog connections or a player with a HDMI connection (and an appropriate surround processor to connect it too). The X-box doesn't have either of these (yet!).
Allan
I've not seen details of the Microsoft update but I'm sure it will be to enable the X-Box to downmix Dolby Digital Plus or Dolby True HD soundtracks to standard DTS at 1.5Mbs. Remember, normal Dolby Digital on a standard DVD is encoded at something like 448kbs and DTS something like 780kbs. So what the Xbox will be doing is taking the higher resolution/lossless audio from a HD-DVD and giving you something that is compatible with a standard surround decoder but of higher quality and bitrate than you would get from normal DVD. Prior to this update, the Xbox would have been doing the exact same thing but downmixing the high res audio to Dolby Digital at about 640kbs.
If you want access to the full quality of Dolby Digital Plus or Dolby TrueHD (lossless) then you will need a HD player that can output audio via multi-channel analog connections or a player with a HDMI connection (and an appropriate surround processor to connect it too). The X-box doesn't have either of these (yet!).
Allan
Posted on: 24 May 2007 by David Dever
1.5Mbps DTS sounds pretty damn good, having done the comparison some time ago when (in a previous life) auditioning processing plug-ins for our post suite.
In fact, if you took five channels of AAC-encoded audio at 160kbps (that's a 320kbps bit rate if encoded as stereo), that'd be only 800kbps! If you consider that 320kbps AAC-encoded audio is "sufficient" for casual listening (highest data-compressed bit rate for use on an iPod), that's more than enough throughput to sound decent....
The only caveat, though, is the fact that there always exists the trade-off between low-latency, real-time encoding (as would occur in this situation) versus multiple-pass, predictive encoding, which would provide better sound quality at the same bit rate.
In fact, if you took five channels of AAC-encoded audio at 160kbps (that's a 320kbps bit rate if encoded as stereo), that'd be only 800kbps! If you consider that 320kbps AAC-encoded audio is "sufficient" for casual listening (highest data-compressed bit rate for use on an iPod), that's more than enough throughput to sound decent....
The only caveat, though, is the fact that there always exists the trade-off between low-latency, real-time encoding (as would occur in this situation) versus multiple-pass, predictive encoding, which would provide better sound quality at the same bit rate.