Martin Ebourne wrote:
On Sat, 17 Dec 2005 10:20:11 -0500, Daniel Kristjansson wrote:
MPEG-1 can handle one or two audio channels, MPEG-2 can handle 5.1
channels with the simple profile, and 48 audio channels with the advanced
profile. I would think it might be best to try to detect the limits of the
sound card, then find matching audio. Or, remix a multi-channel track to
the number of audio channels on the sound card we have, assuming 5.1 or
7.1 configuration when presented with 6 or 8 channel audio, resp..
DTS supports just 5.1 channels, and the 0.1 channel is low freq only.
DTS disks with 6.1 discrete channels definitely exist. I don't think there
are any with 7.1 yet (not sure even if that is possible?). This page lists
some 6.1 titles and has a bit more info at the bottom:
http://www.spannerworks.net/reference/10_6a.asp
That would be DTS-ES.
- AC-3 (a.k.a. Dolby Digital): 5.1 (supports bitrates up to
640Kb/sec, but ATSC limits the bitrate to 384Kb/sec and digital cable TV
standards limit the bitrate to 448Kb/sec)
- DTS (formerly Digital Theater Surround/Systems): 5.1
- *Dolby Digital EX: 6.1 or 7.1 (using matrixed rear channels) -
proprietary AC-3 format extension from Dolby (does not contain a
discrete 6th channel, so not "true" 6.1/7.1)
- *DTS-ES: 6.1 or 7.1(includes a discrete 6th channel)
- *Dolby Digital Surround EX: 6.1 or 7.1 - proprietary AC-3 format
extension from Dolby (includes discrete 6th channel)
- Dolby TrueHD: 8 full-range channels (includes support for lossless
encoding)
- Dolby Digital Plus: 13.1 (includes higher bitrates up to 6.144Mb/sec)
- DTS HD (formerly DTS++): virtually unlimited number of surround
channels that can be downmixed to 5.1- or 2-channel
* Although these support 7.1-channel audio systems, the 6th and 7th
channels are identical (i.e. it's two "rear-center" speakers playing a
mono signal).
Mike
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