AV2 - digital input rates ? LPCM

Posted by: Roy Donaldson on 04 December 2007

Hi there,

I'm sure I saw a post on this, but cannot find it. I can see the FAQ on this, but wasn't exactly clear on it, what LPCM sampling rates, number of channels etc. can the AV2 process via it's optical/coax digital inputs ?

e.g. 5 channels of 96khz, 1.7Mbps etc. ?

Trying to understand the ways of connecting a potential HD-DVD player into my system best.

Thanks,
Roy.

Posted on: 04 December 2007 by David Dever

Can't send more than two channels of LPCM over an SPDIF stream, so your multichannel options are DTS and Dolby Digital...but do check beforehand which type of stream is native to the decoder, as some players re-convert Dolby Digital to DTS internally.

Posted on: 04 December 2007 by Roy Donaldson

So, to connect a HD-DVD player I cannot send multi-channel LPCM in over the SPDIF connector.

I guess my next question would be what are the maximum DD and DTS bitrates in via this path that the AV2 can support ?

Although, I guess that my best path for HD-DVD in then will be 5.1 analog inputs.

Roy.

Posted on: 10 December 2007 by Adrian F.

Hi Roy

This is not specifically AV2 related... As David has said: It is the physical bottleneck of SPDIF! This is the same with BluRay too.

You need a HDMI connection to have enough bandwith for an uncompressed surround sound output in the digital domain. LPCM should be recognised from all versions (if I am not mistaken).

For the new HD sound formats with fewer compression (Dolby Digital plus & DTS-HD High Resolution) or even lossless formats (Dolby TrueHD & DTS-HD Master Audio) a HDMI version 1.3a is needed to put them out as native bitstream. Of course the external processor needs to know these new formats (which is not mandatory, even when it has 1.3a).

Most (if not all) HD players should have a backwards compatibility setting. They let the HD sound "extension" away, and give only the "core" out over SPDIF. This confirms to the old DVD formats, and the max. will be 640kbps for Dolby Digital and 1.5mbps for DTS. Theoretically, even this could sound better, because the data rate on DVDs is usually much lower than the max. allowed by the definition.

Check to see if your player has analogue outputs? At the moment, only the "top" models have. The result depends from the players built quality. Sometimes the players don't have full surround setup parameters for their integrated processors... (It will not be the AV2 that sets the parameters over the analogue multichannel input.)

happy HD listening
Adrian