Splitting HMDI Audio from video

[Frankdaatank24]

The problem: I'm deploying soon and taking my computer with me, and I will use the monitor to connect both my PC and XBOX 360. When connecting my XBOX 360 to my HP w2207 monitor via HMDI I am forced to use the crappy speakers on the monitor.

What I need to happen: Some how split the audio portion of the HDMI signal to output to a standard audio output port that I can connect 2.1 speakers to.

I've searched for adapters, and there all like $80 and they don't even do what I need them to do. I could engineer one I think, but I would have to do a ton of research and figure out the pin outs on the cable, and I'm sure its all proprietary. Anyways, any help on this would be awesome.

 

[mpilchfamily]

I beleive this is what your looking for.
http://www.amazon.com/gp/product/B000UODATY

As you can see in the link below it gives you a cable that plugs into the A/V port on the X360 and doens't block the HDMI port. That cable gives you the audio connections you'll need to hook up the system to wither your PC or other sound system.
http://www.amazon.com/gp/custo...ages_0?ie=UTF8&index=0

 

[Frankdaatank24]

Ahhh, I see. How convenient of them to hide the HDMI port when the A/V cables are installed. Looking at my connector now I see that its abnormally big, obviously not by accident. So, I need shell out 50 more bucks to M$... awesome...

Thanks though man, I really appreciate it.

 

[Modelworks]

Unfortunately the video and audio are encoded together on HDMI, it isn't like other types of wiring where the audio is on a separate wire.
So you can't just separate one from the other without some circuitry involved.
That is why you see such high prices for devices to do that.

 

[Frankdaatank24]

Yea, shortly after my last post I did a google for the pin outs on HDMI cables, and yea all I saw was clock, data, and grounds. Makes sense now that I think about it. I wonder if it would be possible to make a CB with a decoder chip on it for cheap...

 

[Modelworks]

Originally posted by: Frankdaatank24
Yea, shortly after my last post I did a google for the pin outs on HDMI cables, and yea all I saw was clock, data, and grounds. Makes sense now that I think about it. I wonder if it would be possible to make a CB with a decoder chip on it for cheap...

Sadly you can't.
Blame the MPAA.
The chipsets for decoding HDMI can be bought, but the datasheets which contain all the info you would need to use the chips is under lock and key. You have to sign a NDA with the makers of the chips to get the datasheets.

They are the whole reason it is encoded with the video , so they can turn on HDCP and prevent anyone from copying .

 

[Frankdaatank24]

I'm down with signing a NDA, I'm not going to give out the code to anyone, although I'm sure people a lot smarter than me can figure out the encoding if they had an HDMI chip set.

So, hypothetically speaking, I want to start a company and I figure out the schematics necessary to make a dongle so to speak to split the HDMI signal into video and audio. Would I have to fork out a boat load of cash in order to sign this agreement? Or would all I have to do is purchase the chips and then sign the agreement? Or what?

 

[Modelworks]

Originally posted by: Frankdaatank24
I'm down with signing a NDA, I'm not going to give out the code to anyone, although I'm sure people a lot smarter than me can figure out the encoding if they had an HDMI chip set.

So, hypothetically speaking, I want to start a company and I figure out the schematics necessary to make a dongle so to speak to split the HDMI signal into video and audio. Would I have to fork out a boat load of cash in order to sign this agreement? Or would all I have to do is purchase the chips and then sign the agreement? Or what?

The first step is making contact with one of the companies that holds the information.
The main one being Broadcom.
There is also the cost of development kits which range in cost anywhere from $5K to $25K.
http://www.broadcom.com/products/applications/HDTV

It isn't as simple as call them up and signing a NDA. It is very similar to getting approval from Dolby to build 5.1 decoders. Generally they require a business plan, saying what you want to design, who the engineers are, your target market and how many chips you are interested in. Don't bother talking to them if you intend to make less than 1,000 units.

Broadcom can be hard to deal with, but then they have their chips in everything from cell phones, cable modems, dvr boxes, etc, so they take security seriously.


You might have better luck with Analog Devices.
The do at least give the datasheets, but not all the data you would need.
http://www.analog.com/static/i...data_sheets/AD9381.pdf

They will let you see the datasheet, but then they license the actual chips.

So Broadcom - you get chips, but can't get datasheet
Analog Devices - you get datasheet, but can't get chips

 

[mitchafi]

There was another thread on here that just advised to pry the big plastic cap on the standard AV (red, yellow, white) adapter off, allowing it to plug in simultaneously with HDMI. That's what I did, and it works fine for my purposes (using the 360 on a projector with no audio inputs). I'm not sure if this is what you are getting at, but just thought I'd throw it out there.

 

[Frankdaatank24]

Yea I tried that, the plug is still too big. I'll add that I'm not using an XBOX HDMI cable either...