Dolby TrueHD, Dolby Digital Plus, and DTS-HD Master Audio can not be carried by optical or coaxial digital audio. The best that optical/coaxial can do is carry Dolby Digital or DTS - which is why many players have been decoding the new formats and then re-encoding as high-bitrate DD or DTS.

There are a limited number of different ways to handle audio from HD-DVD and Blu-ray players:

1. HDMI v1.3: Pass the undecoded digital bitstream from disc to receiver/processor. Presently impossible because there are no HDMI v1.3 receivers or processors.
2. HDMI v1.1/1.2: Player decodes the bitstream to multichannel PCM and passes the decoded multichannel PCM via HDMI to the receiver or processor.
3. Multichannel Analog: Player decodes the bitstream to multichannel PCM, then converts the PCM to multichannel analog.
4. SPDIF Digital Audio: In cases where the disc contains a legacy digital audio format (Dolby Digital, DTS, or the DD and DTS tracks embedded in Dolby Digital Plus and DTS-HD specifically for backward compatibility), that data can be passed via optical or coaxial. In cases where there is not a legacy digital audio format in play (such as TrueHD), many players will decode the new format and then re-encode as either high-bitrate Dolby Digital or high-bitrate DTS.

Those are our only options.