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HD-DVD to HD-TV to AVR: lose Dolby Digital

post #1 of 7
5/4/07 at 12:29am
Thread Starter 
If I run my Toshiba HD-A2KU DVD via optical cable directly to my Harmon Kardon AVR, I get DD2.0; however, if I run the DVD via HDMI to my Toshiba 42HL167 HD-TV, then via optical from the TV to the AVR, I get only PCM, even though the TV seems to say it will deliver DD2.0 to the Amp through its optical output.

I was hoping to use the single path: DVD to TV to Amp, but have to use the other route as well. Is the digital signal from the DVD to the TV downgraded after coming through the HDMI, or is the TV doing something to it? (At least changed enough that my non-HDMI AVR cannot sense it properly?)

TIA,
GHuston
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post #2 of 7
5/4/07 at 3:43pm
TV reports to DVD that it supports only stereo, then DVD sends to TV stereo only - that's by design. DVD -> TV -> Amp won't produce the best audio you'd like to have. In your case - non-HDMI AVR - you need DVD -> TV & DVD -> Amp.
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post #3 of 7
5/4/07 at 4:25pm
Some TVs can accept DD on the HDMI input, and then they downconvert for own speakers, while passing along the DD stream on a SPDIF output connector. That's probably what you expected, but it appears your TV will only report that it can accept 2ch stereo on its HDMI input.

Other TVs have the SPDIF output connector on their mainly to extract the DD from its built in ATSC tuner and send to your AVR.

Your other option is the run HDMI from the player to the TV, and then optical from the player to your non-HDMI AVR. This is what many users with a non-HDMI AVR do.
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post #4 of 7
5/5/07 at 6:10pm
Thread Starter 
Thanks for the replies.

To excerpt from my manual: "The TV's DIGITAL AUDIO OUT terminal outputs a Dolby Digital or 2-channel down-mixed PCM signal for use with an external Dolby Digital decoder or other external audio system with optical audio input."

Also: "In the Optical Output Format field, select either Dolby Digital or PCM," of which I selected the DD.

It *does* say, however, that "Some audio systems may not be compatible with Dolby Digital bitstream signals," so that may be what I'm facing ... although is it likely that the signal is any different than the one straight from the DVD player (which does give me DD)?

Thanks again,
GHuston
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post #5 of 7
5/14/07 at 5:33pm
HDMI_Org got this question on the dot.

But to answer GHuston's question, the Optical Output Field for DD or PCM is for the ATSC/QAM tuners in your TV. The systems that aren't compatible with DD would be old stereo/PCM recievers(there probably wouldn't be a optical input on these).

Maybe in the future, there could be a firmware update to change this to make it DD from DVD(or HD-DVD/Blu-Ray) to TV which would output the same signal to AVR.

The signal coming from DVD to TV is stereo, and then to the audio system which is still stereo, so Dolby decoding is not needed because there isn't a bitstream to decode.

Audio codecs that are used to inputs of the TV are usually:
ATSC/QAM - DD 2.1/5.1 and PCM, sent to reciever by optical out(PCM sent by RCA, some do PCM over optical too)
DVD/VCR or any analog device by RCA to TV - PCM sent by RCA
DVD by HDMI to TV - PCM(stereo) sent by HDMI to TV, TV to reciever PCM sent by RCA/Optical.

Hopefully this answers any doubts or questions or any "what ifs?".
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post #6 of 7
5/18/07 at 1:56pm
Thread Starter 
Thanks much, mapper.

So, if I understand correctly, the DVD player is only sending a stereo signal to the TV, and passing that on to my AVR via the Optical output from the TV?

If that is the case, where does the DD signal come from into the TV, that *could* be passed out through its Optical (as the manual states), if not from a DVD player? Would it be assumed to be coming from some other DD source?

The book says -- although stereo is going to the TV -- that the DD is being passed through from the DVD (HDMI), and can be tapped at the Optical out from the TV.

My AVR *does* have Optical input, and gives me DD when hooked directly to the DVD player using the Optical (which is the usual workaround, I understand). Is the DD coming from the TV's Optical in a different format?

Thanks,
GHuston
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post #7 of 7
5/18/07 at 4:25pm
From digital tuner.
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