DirecTV HDMI cable, pointless?

Anyone? My roommate got DirecTV with the HD package and all that jazz. Is there an advantage to using the HDMI cable though? All the materials talk about it sending both the HD video and a digital audio signal over the same connection, but it doesn’t send a Dolby digital audio signal. We still have to use the optical output on the back of the DirecTV receiver for that. In fact, you don’t even get audio mixed back down to stereo through the HDMI cable when watching 5.1 programming, if we have the box set up to output Dolby digital surround and don’t plug in the optical cable, we get no sound at all through the HDMI cable. I thought HDMI was supposed to be the top-end, so what’s the deal? Am I just misinformed on HDMI’s capabilities, or is there some dumb reason specific to DirecTV that it can’t send the Dolby digital signal over the HDMI cable?

I don’t have DirectTV, but I use HDMI for my DVD player and have no problems with the audio.

Can you elaborate?

We have a 5.1 surround system with optical inputs. The TV has an optical output. The DirecTV system has an optical output as well, but to eliminate having to fuss with selecting a bunch of different sources, we thought we would go from the DirecTV receiver to the TV via HDMI, and then use the TV’s optical output into the surround system’s optical input. Other stuff (like the Gamecube) could then be plugged into the TV and it would still have its audio sent out via the optical cable, it would just be stereo, as well as all the non-5.1 programming from the DirecTV box. That way we’d only ever have to swap sources on the TV, we wouldn’t have to switch sources on the receiver as well.

The problem we discovered is that the HDMI connection from DirecTV won’t send 5.1 audio, and I was curious whether this was an HDMI limitation or just a bizzare DirecTV limitation. We can still get all the regular stereo audio from the DirecTV via the HDMI cable, and if we disable Dolby digital audio output, it will just send stereo for that as well over the HDMI cable, but if we activate Dolby digital output and switch to some programming that uses it, it sends no audio over the HDMI cable, and the 5.1 comes through the DirecTV optical output (that we were trying to avoid using).

Are you going from your DVD player into some 5.1 sound system with your HDMI cable and getting a separated signal? That’s really all I’m curious about, if HDMI can do this or not; I want to know where exactly to channel my frustration :)

It’s not a technical limitation of HDMI. What I suspect is happening is that the translation from HDMI into the TV, then optical out to the receiver, isn’t passing through or converting properly.

[quote=“Case”]

It’s not a technical limitation of HDMI. What I suspect is happening is that the translation from HDMI into the TV, then optical out to the receiver, isn’t passing through or converting properly.[/quote]
Well that answers my question about HDMI’s capabilities, and it is possible something would be lost in the transition through the TV, but I doubt it. I think it’s still just a (stupid) decision on DirecTV’s part, no fault of the TV’s:

They’re pretty clearly saying the optical cable is the only way to get your Dolby Digital out, and if it’s not a limitation of HDMI, then I think it’s pretty retarded. The only vaguely plausible reason I can think of is they’re just assuming not many TVs will have an optical out, so they didn’t think there’d be a reason to send the data to your TV. Still seems like a dumb choice.

I would search through the TIVO forums to see if anyone else has this issue. I haven’t gotten an HD TIVO but I’d like to and I would also like to have the HDMI plugged into the TV and the optical audio from the TV to the receiver (I already have this for OTA reception). I’m not sure if some or any TV can even transfer the DD5.1 from HDMI to the optical audio out. Hopefully my new Aquos can.

I’m interested to see what you find though. I’ll check it out myself when I get a chance.

edit: this thread looks like it relates:

Well, if you’re still having to run an optical cable out from your TV to the AV receiver, there’s really no benefit of having the HDMI cable carry both the video and digital audio signal. The main benefit of HDMI is the better picture quality and being able to have the audio and video connection in one cable for people not listening through a surround receiver. If you’re trying to get 5.1, it’s no less trouble just going optical out of the sat box to the receiver than the way you’re trying to do it because either way you’re going to have to tell the surround receiver which source you want to listen to.

No, if the DirecTV box had worked the way I thought it would, I would never have to switch inputs for the receiver. Just always leave it on the optical input. Which everything that came into the TV would come out on.

It’s not a huge issue, it just means toggling the reciever over to different sources whether I’m using the optical in from the DirecTV or a stereo input from the Gamecube, but it’s frustrating to not see the logical reason why it wouldn’t work as I described.

Jazar, I have no idea if this is the same for the DirecTV HD flavor of TiVo as the non-DirecTV HD TiVo.

EDIT: Jazar, skimming that thread, it appears the same is true for the HD TiVo, you can’t send DD through the HDMI cable, only optical.

As for the capabilities of the TV, I suppose I’ll go read the manual, but the fact that it has an optical out at all really makes me think it could pass a DD signal from an incoming HDMI to the outgoing optical cable, but I don’t have any way of testing it. It does have a slot for a cable card though, so I suppose it’s possible that the only optical out usage could be if you were getting your HD content from cable card your cable company sent, because with no external cable box (or DirecTV reciever) that’d be the only way to get the optical signal. Seems odd to only have the optical output on the TV used for that specific scenario though, especially since it can pass regular audio in my setup.

well there’s only one HD-Tivo and that’s the DirectTV one.

Does your TV have an internal HD tuner for over the air broadcasts? The OTA broadcasts are in 5.1 and output to my receiver for dolby digital.

I’m not sure, I know you need an HD antennae to pick up the OTA broadcasts, so I guess yes? That would be another use for the optical out, you’re right. It’s a 50" Samsung DLP, I’ll go check the model number in the morning.

Still, I can’t find any rhyme or reason for not sending the DD audio over the HDMI unless no TVs could pass it through. Which I guess is possible, but it’s not immediately obvious why that would be the case, so for someone new to HD and DirecTV and all this stuff, it seems retarded.