HD DVD players decode the audio -- not the AVR

[bobgpsr]

I got asked a question via PM about how to set up an AVR for the advanced codecs used with HD DVD such as DD+ and Dolby TrueHD. After answering I thought that the info could use repeating here with a normal post.

For HD DVD the player must decode any audio codec used on an Advanced Content HD DVD title (most all HD DVD's are authored as Advanced). The player then mixes the audio with button sounds and with PiP (HDi) commentary audio. It sends the resulting audio out the HDMI interface as multichannel linear PCM which is what an AVR will show (MPCM). Everything is working normal, you are getting the full benefit of the HD DVD audio since multichannel linear PCM is lossless. Nothing to change in your AVR. You are all ready to select and fully benefit from a Dolby TrueHD lossless audio track on a HD DVD that offers it as a choice in its menu (the HD DVD menu or the player's remote control Audio button).

The other lossless audio connection option is with the 5.1 analog outputs that the Toshiba HD-XA2 and earlier 1st gen (HD-A1, HD-D1, HD-XA1) have. This is connected with 6 RCA patch cables to your AVR/Pre-Pro's 6 channel (Multi Channel) input. Often there is a discrete button on the front of an AVR or remote control to select this direct 6 channel input (aka Multi Chan Input).

An industry common practice is to require that the AVR/Pre-Pro or the subwoofer boost the LFE analog by +10 dB to get the proper Dolby/THX LFE playback level. Movies expect the normal channels to have audio peaks at +105 dB SPL but the LFE channel to peak at +115 dB SPL. Such boost is automatically done internally in an AVR when connected by a digital S/PDIF (coax or optical Toslink) connection that uses legacy DD or dts audio codecs. But the boost is not normally done with a 5.1 analog input connection -- it requires deliberate action by the user to configure it right. Some AVR/Pre-Pro's have a special option to do the +10 dB boost needed for LFE. Another way is to do a separate 5.1 analog input calibration (most AVR's can do a different cal for S/PDIF) where you boost the subwoofer gain at the subwoofer amp by +10 dB.

Note that this extra effort to get the right +10 dB LFE boost on an 5.1 analog connection is common need/practice for SACD, DVD-Audio, HD DVD and Blu-ray players. I understand that the need for this boost is to avoid line level clipping in the player's output stage or the AVR/Pre-Pro's input stage.

Some AVR's (Denon ?) have a similar +10 dB LFE boost option for the multichannel linear PCM input via HDMI.

Any HDMI (1.0, 1.1, 1.2a, 1.3) interface can carry multichannel linear PCM. HDMI 1.3 is not required. The 1.3 version can carry the raw undecoded bitstream for DD+, Dolby TrueHD, dts-HD HR and dts-HD MA. But that feature (raw bitstream) gets disabled when the user requests PiP with commentary audio that must be mixed in inside the player.

Hope this helps a little bit. I know that it is confusing to a newcomer.
Bob

[Sonnie]

Great explanation Bob... most excellent...

Thank you!

[MACCA350]

bobgpsr wrote:

For HD DVD the player must decode any audio codec used on an Advanced Content HD DVD title (most all HD DVD's are authored as Advanced). The player then mixes the audio with button sounds and with PiP (HDi) commentary audio. It sends the resulting audio out the HDMI interface as multichannel linear PCM which is what an AVR will show (MPCM). Everything is working normal, you are getting the full benefit of the HD DVD audio since multichannel linear PCM is lossless. Nothing to change in your AVR. You are all ready to select and fully benefit from a Dolby TrueHD lossless audio track on a HD DVD that offers it as a choice in its menu (the HD DVD menu or the player's remote control Audio button).

This also applies to Blu-ray discs encoded with "Profile v1.1" or higher.

cheers

[Blaser]

Does any HD or BD player have 7.1 output audio?

[bobgpsr]

blaser wrote:

Does any HD or BD player have 7.1 output audio?

Likely for linear PCM if the title author can fit it. Have not heard about any player having audio codec decode to more than 5.1 channels.