I recently hooked up a Sony LCD panel and thought I'd simplify things by running all the inputs directly to the TV and then run the TV's optical audio output to my AV receiver.

My thinking was that this way all the switching of audio and video would be accomplished in one place (the TV) and the AV receiver would essentially be used to just decode the optical audio stream and amplify it for the speakers using this one simple connection.

It does not work. This surprised me.

I have two devices connected to the TV by hdmi sending both video and audio over these links. The TV can obviously decode and play the audio for each of these links as it works perfectly through the TV speakers. I was expecting this same audio signal to be sent out on the optical audio output jack. Anyone know why this doesn't work?

Is is typical for TVs to have this limitation? Seems like a really bad design if so. It would be so convenient to switch in only one place.

It's typical, the output is only intended to be used to supply audio from the internal tuner. Most TV's only process two channels audio via the HDMI chipset because they only need to reproduce stereo sound therefore the rest is dropped. They'd have to design the sets to accept 5.1, downmix it to 2.0 and pass everything along to the optical output, guess it's not worth it to them to add that in in the off chance you want to use the display as a pass through.

It's typical, the output is only intended to be used to supply audio from the internal tuner. Most TV's only process two channels audio via the HDMI chipset because they only need to reproduce stereo sound therefore the rest is dropped. They'd have to design the sets to accept 5.1, downmix it to 2.0 and pass everything along to the optical output, guess it's not worth it to them to add that in in the off chance you want to use the display as a pass through.

Thanks Matt,

I was afraid that might be the case that this was typical. Still it's hard to believe it's not implemented this way. It seems to make so much sense to switch all your audio and video in one place.

As far as I know, most (cheap) AV receivers can't process video right? Or can they now? I mean, if I have an hdmi device and a component device plugged into my AV receiver can I expect it to send either of these video streams over an hdmi link to the monitor?

It would have to convert analog component to hdmi digital it that case.

Thanks Matt,

I was afraid that might be the case that this was typical. Still it's hard to believe it's not implemented this way. It seems to make so much sense to switch all your audio and video in one place.

As far as I know, most (cheap) AV receivers can't process video right? Or can they now? I mean, if I have an hdmi device and a component device plugged into my AV receiver can I expect it to send either of these video streams over an hdmi link to the monitor?

It would have to convert analog component to hdmi digital it that case.

There are a number of AV receivers that can convert all their analog inputs to digital for output over HDMI, not sure if they fall into the cheap range yet though...

With devices like Blu-Ray passing newer audio codecs other then DD, you wouldn't want to send them directly to the TV either..

There are a number of AV receivers that can convert all their analog inputs to digital for output over HDMI, not sure if they fall into the cheap range yet though...

With devices like Blu-Ray passing newer audio codecs other then DD, you wouldn't want to send them directly to the TV either..

I would want to send these audio streams to the TV if the TV had the ability to simply implement a switch and pass them on to its audio output.

The audio output could be upgraded to hdmi. My guess is it will become standard one day.

I would want to send these audio streams to the TV if the TV had the ability to simply implement a switch and pass them on to its audio output.

The audio output could be upgraded to hdmi. My guess is it will become standard one day.

But those codecs will never go over optical, due to (a) industry desire for protection, and (b) the bandwidth requirements of the advanced codecs. Besides, the entire point of a proper receiver setup is to make *it* your one-stop place for managing all the incoming video/audio signals, and have your TV be just a display device. So... no. The cost would be ridiculous, and you'd have to have an HDMI out from your TV just for those advanced codecs. It won't happen, nor should it. Get a decent receiver and call it done. :)

Edit: My Onkyo TX-SR674 does convert all inputs (composite, S-Video, component) to HDMI. I bought it for ~$500 around 3 years ago. I'm sure you can find something in a similar price range with the same functionality these days - this is hardly top of the range gear here.

But those codecs will never go over optical, due to (a) industry desire for protection, and (b) the bandwidth requirements of the advanced codecs. Besides, the entire point of a proper receiver setup is to make *it* your one-stop place for managing all the incoming video/audio signals, and have your TV be just a display device. So... no. The cost would be ridiculous, and you'd have to have an HDMI out from your TV just for those advanced codecs. It won't happen, nor should it. Get a decent receiver and call it done. :)

Yes, a decent receiver with video processing abilities would be my preferred solution too. One simple cable to a monitor on the wall.

But since most consumer TVs already have all this video and most of the audio processing in place it seems logical they go one last step and make the audio available as an output, or else remove it all and save money.

The bottom line is: Do all your switching in an "AV Receiver" that has more processing options than a one-trick-pony TV set. It also has enough amplification to feed 5.1 channels of audio, or more.

HDMI is more about a single-wire connection solution (with a healthy dose of Hollywood paranoia thrown in) than it is about flexibility of functions. Your desire to turn a TV set into an AV processor, while "logical" to you, doesn't offer many advantages. While the TV has the decoder necessary to watch DTV, it doesn't have encoding hardware to take whatever might come down the HDMI cable and turn it into a digitally encoded signal. In reality, the digital output on your TV is there because it's cheap to implement and often doesn't require any decoding hardware in the set at all.

The bottom line is: Do all your switching in an "AV Receiver" that has more processing options than a one-trick-pony TV set. It also has enough amplification to feed 5.1 channels of audio, or more.

HDMI is more about a single-wire connection solution (with a healthy dose of Hollywood paranoia thrown in) than it is about flexibility of functions. Your desire to turn a TV set into an AV processor, while "logical" to you, doesn't offer many advantages. While the TV has the decoder necessary to watch DTV, it doesn't have encoding hardware to take whatever might come down the HDMI cable and turn it into a digitally encoded signal. In reality, the digital output on your TV is there because it's cheap to implement and often doesn't require any decoding hardware in the set at all.

The TV already has the digital audio from the HDMI input. It doesn't have to re-encode it, it could just pass it through to output.

Most likely it is all about cost. As you said, the optical audio out is there in 2 channel form because it is cheap.

So how much does one have to spend these days to get a decent cheap receiver that can convert all video inputs to HDMI?

I guess it's hard to quantify "decent" or "cheap". Let me just ask what the lowest priced unit out there now that has this ability? Just as a reference point.

The TV's can output 5.1 over optical when you're watching something on the internal tuner that is receiving it, they just can't pass 5.1 through from HDMI.

As for the receiver, it would be a better question to ask in the AMPs, Receivers, and Processors section under Audio.

The TV already has the digital audio from the HDMI input. It doesn't have to re-encode it, it could just pass it through to output.

If you are watching a 5.1-channel source on HDMI it has to be encoded to be passed over the TV's digital output. Only stereo could be "passed."

Most likely it is all about cost. As you said, the optical audio out is there in 2 channel form because it is cheap.

The only reason there is a digital output (optical or coaxial) on a TV is so it can pass the Dolby Digital signal that it receives OTA or on QAM cable. It can also pass a downmixed stereo version of the program if you tell it too.

So how much does one have to spend these days to get a decent cheap receiver that can convert all video inputs to HDMI?

I guess it's hard to quantify "decent" or "cheap". Let me just ask what the lowest priced unit out there now that has this ability? Just as a reference point.

There appear to be three-tiers of HDMI-compatible AV receivers :

1. Switchers - they simply switch the HDMI video, and don't do anything with the audio - you still need a separate SPDIF/Toslink audio feed. These don't exploit the additional quality of HDMI audio - and are just basically a regular SPDIF/Toslink amp with an HDMI switch grafted on.

2. Switchers with Audio - they switch the HDMI video and process the HDMI audio - some are PCM/DD/DTS only and don't handle bitstreamed DD+, True HD or DTS HD. If you want to feed component/composite you have to route separate outputs from your amp to your display - they don't do any conversion from Component/Composite to HDMI. If you only have HDMI sources - and your sources decode to PCM audio (if True HD and DTS HD aren't bitstream supported) - then they can be a very good buy.

3. Switchers with Audio and Video A/D Conversion - they switch the HDMI video, process the audio (often now with True HD and DTS HD decoding) and will convert analogue composite/component video to HDMI (often with some upconversion) You just run a single HDMI cable to your display, with the amp converting all analogue sources to HDMI and handling all audio duties. Neat solution if you have lots of non-HDMI sources - and often the "higher end" solution when it comes to audio codec support.

1. are becoming unheard of now, and 3. are getting much cheaper.

My first HDMI amp - a Sony 820 was in category 2 (but it's PSU blew up inside warranty). My current Onkyo SR606 is category 3.

One thing not mentioned is "why".

If I'm not mistaken, the main reason TVs (and all other kinds of devices) don't pass HDMI audio through to a digital audio output is that the HDMI (or is it HDCP) spec forbids it. If a device passes any audio at all, it must be converted to Stereo PCM.

I too find it very irritating. Most of the time I want to watch TV without turning on my receiver. I can do it, but I can't have the best of both worlds - whenever I do want to listen to 5.1 audio via my receiver, I have to reconfigure at least two devices (optical out settings on my DVD player, input settings on my receiver).

A hex on Hollywood's paranoia. Once again legitimate customers suffer.

One thing not mentioned is "why".

If I'm not mistaken, the main reason TVs (and all other kinds of devices) don't pass HDMI audio through to a digital audio output is that the HDMI (or is it HDCP) spec forbids it.

Well, I think that depends on the format. Advanced audio codecs used by Blu-Ray and HD-DVD aren't passed because of the desire for protection, and because it's not possible over optical/coaxial due to S/PDIF bandwidth limits. TVs generally don't deal with DTS at all, and hardware or code would have to be added and tested to handle it properly, and additional licensing and certification costs to do *anything* with another format. Dolby Digital gets downmixed because of the internal signal paths making it much simpler to downmix. As usual, I don't think it's some far reaching conspiracy, it just works out to be simpler that way - and the fact that it restricts you from doing something the industry doesn't particularly like is just a convenient coincidence.

I too find it very irritating. Most of the time I want to watch TV without turning on my receiver. I can do it, but I can't have the best of both worlds - whenever I do want to listen to 5.1 audio via my receiver, I have to reconfigure at least two devices (optical out settings on my DVD player, input settings on my receiver).

Let me know when you want to pay the additional engineering and certification costs so that your TV can pass these formats for a few corner cases. The TV business is already pretty cutthroat, I think, and either (a) the additional cost would cut into margins, or (b) it would drive up their prices, making their displays cost that much more than the competition's.

Not everything is a far-reaching conspiracy. There are good reasons for doing what they do. Just because you don't *like* it doesn't mean they're out to get you.

What if the input to the TV is via componet cables will the TV's optical audio output pass it thru or will it be the same as with HDMI? I am just about to buy an audio system and was planing on doing exactly as the poster described.

What if the input to the TV is via componet cables will the TV's optical audio output pass it thru or will it be the same as with HDMI? I am just about to buy an audio system and was planing on doing exactly as the poster described.

Errm. Component cables don't carry audio in and of themselves. Normally either stereo analog cables (the red-white pair) or an optical or coaxial digital connection is used. Just connect the digital audio feed into your receiver; of course, keep in mind that if you're using a Blu-Ray player, you won't be able to get the advanced audio formats into your receiver without HDMI or multichannel (5.1/7.1) analog. That may or may not matter to you though, depending on your setup.

Actually, this "pass-through" depends on both the input device, and the TV capability.

Example - Comcast/Motorola DVR DCT-6415 connected via HDMI to Mitsubishi WD-65732 DLP TV, to Sony A/V receiver.
This setup passes the 5.1 through to the receiver. No issues. But... connect a DVD player or Blu-ray, only PCM passes through the TV.

Errm. Component cables don't carry audio in and of themselves. Normally either stereo analog cables (the red-white pair) or an optical or coaxial digital connection is used. Just connect the digital audio feed into your receiver; of course, keep in mind that if you're using a Blu-Ray player, you won't be able to get the advanced audio formats into your receiver without HDMI or multichannel (5.1/7.1) analog. That may or may not matter to you though, depending on your setup.

Think i will split the audio out of the cable box, one to the TV and one to the sound system box and go with component to the TV. I do have Comcast with a Motorola box but hate to buy a optical cable for it not to work. Like the original poster I would like to be able to choose what sound I want.

I am getting a Phillips DVD home theater system. Here is what i want to do. Operate TV via Component & Audio cables from cable box. HDMI from DVD player (same box as home theater) to TV. Run optical SPDIF audio cable from cable box to home theater system. This way I can choose which sound I want. Am i missing something here?