Author Topic: hdmi cec  (Read 19559 times)

wierdbeard65

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Re: hdmi cec
« Reply #15 on: October 13, 2010, 07:46:41 pm »
Looks interesting and, from the Blurb, should work with both Linux and my TV. A little expensive, but there you go  :-\

What is not clear is if it can be placed "in line" between the graphics card and the TV. If not, you would end up with 2 HDMI cables to the TV which partially defeats the object!

I may contact this guy to see what the possibilities are - might be an interesting first journey into device / template design....
Paul
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posde

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Re: hdmi cec
« Reply #16 on: October 14, 2010, 10:42:46 am »
good luck and keep us posted.

Sigg3.net

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Re: hdmi cec
« Reply #17 on: January 03, 2011, 04:11:37 pm »
Apparently, CEC-wiring is mandatory in HDMI but product implementation voluntary.

According to Wikipedia different trade names for the IMPLEMENTED CEC are:
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Anynet (Samsung); Aquos Link (Sharp); BRAVIA Sync (Sony); HDMI-CEC (Hitachi); Kuro Link (Pioneer); CE-Link and Regza Link (Toshiba); RIHD (Remote Interactive over HDMI) (Onkyo); SimpLink (LG); HDAVI Control, EZ-Sync, VIERA Link (Panasonic); EasyLink (Philips); and NetCommand for HDMI (Mitsubishi).
Source: http://en.wikipedia.org/wiki/HDMI#CEC

The specification is built on AV.Link, which is used in SCART.
You can download the HDMI 1.3a specification for free by filling in the form here: http://www.hdmi.org/manufacturer/specification.aspx

It exists a HDMI-CEC to USB and RS-232 bridge/converter as featured on Hackaday. This guy Valkyriemt made it work for him: Controlling Volume… Look Ma, no extra Wires!

A white paper on what this device does and how to use it can be downloaded here: PDF

Rainshadowtech.com which makes the device writes:
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(HDMI-CEC to USB and RS-232 converter) device has been demonstrated to work with TVs from Samsung, Sharp, Sony, Toshiba, LG, Panasonic, and Mitsubishi.  TV CEC capabilities vary widely.  Many recent models can be powered on, off, and have the external HDMI input source chosen via CEC.
an
Quote
This device could be connected into the HDMI cable between the TV and the PC, but that is not necessary. Because the CEC bus is a single wire bus between all components, the device can be plugged into any HDMI input in the Home Theater system. The advantage of this approach is that the integrity of the cable (and therefore the quality of the signal) between the TV and the PC does not need to compromised by adding this device to it.

As far as I understand it having merely looked at the HDMI specs, the specification allows for pass-thru signalling; meaning one sleeping device will still pass through messages (such as SHUT DOWN) to other connected devices that are on or off. In other words, HDMI cables can become an extension of the network cabling for LinuxMCE to talk to devices directly the last-three-feet.
--

I personally have a Toshiba REGZA 42" (42XV550P) Television that I bought a couple of years back, and it doesn't have a serial RS232 controller. It does have 3 HDMI connectors though. I am not much of an electronics guy either, but I think we should be able to wing it.

The remote control for my Toshiba REGZA 42" has its own REGZA Link mode, which is Toshiba's implementation of HDMI's CEC, though sending them using IR. Showcase: http://www.regza-asia.com/technology/technology_regzalink.asp?cat=sc4

If I can record the IR signals sent to the television in REGZA Link mode, I should be able to send the same signals from a computer to the television (and other CEC devices), given I have a way to interface with HDMI with on the command-line and a HDMI controller on the computer. From this it should be possible to create a device template or "device class template" (e.g. REGZA-device), no?
The CEC specification has its own addressing scheme (think DHCP) with logical addresses 4, 8 and 11 reserved for playback devices.

The CEC wiring IS MANDATORY so you would not need more than one HDMI cable between computer and television, since the wiring for the CEC signalling is already inside the cable (in other words, HDMI cables send CEC along with VIDEO and AUDIO). But I don't know exactly what tty you could use (if any).. Just some thoughts on the matter..

Sigg3.net

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Re: hdmi cec
« Reply #18 on: January 04, 2011, 06:33:46 pm »
Some of the hackers on the arduino.cc forums are working on a chip with some success: http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1261237176/0

One user Phil123 is working on a breadboard design that:
Quote
tAt the end there will be a breakout board for the Arduino which has 2 HDMI connectors (in/out). One will be connected to the TV set, the other to a HTPC. The CEC in/out will be sent/received via the USB connection to a PC. That way a HTPC can be driven by the remote control of the TV set.
URL:  http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1261237176/30

He put up sourcecode here: http://code.google.com/p/cec-arduino/
Circuit schema here: http://code.google.com/p/cec-arduino/wiki/ElectricalInterface

One Andrew put up a nice excel table of the opcodes: http://www.andrewncarr.com/hdmi/hdmi-cec-codes.xls

Of course, this all amounts to using the CEC hacked android breadboard and not the built-in HDMI in the mobo/VGA cards. But I thought I should mention it anyway.

According to Mark E. DeYoung neither ATI nor nVidia is building CEC into their cards (source)

valent

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Re: hdmi cec
« Reply #19 on: January 10, 2011, 10:41:23 am »
Regarding HDMI-CEC, as pointed out elsewhere in the forum. There is a USB2HDMI-CEC device available. If anyone is willing to do dev work on integrating it into our system, or sponsor other people to do so, lmce has all the plumbing in place to control devices via HDMI-CEC.

I'll be glad to sponsor dev work regarding HDMI-CEC feature for lmce. But as my budget is proabably not enough alone has if some lmce dev says how much they would need to get this done maybe we can try setting up an pledge bank or something like that? What do you say?
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kwikwai.phil

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Re: hdmi cec
« Reply #20 on: January 20, 2011, 03:56:40 pm »
Hi guys,

actually I guess I have something for you.
Have a look to kwikwai. It's a HDMI-CEC bridge to ethernet, usb and serial.
You might find it helpful.

Now if you still prefer to develop a solution by yourself, give a try to cec-o-matic, a free online CEC frames encoding/decoding tool.
It should help.

Regards,
Philippe

posde

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Re: hdmi cec
« Reply #21 on: January 20, 2011, 05:54:20 pm »
Phillippe,

it might interesting for you, if people could pnp your bridge, and have LinuxMCE control the devices via HDMI. Maybe you light to look into writing a device driver, so LinuxMCE users can be come kwikwai customers :)

wierdbeard65

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Re: hdmi cec
« Reply #22 on: January 20, 2011, 06:09:15 pm »
Phillippe,

I just had a quick look and it would seem to be a very interesting little device, until I got to the store.

The price is quoted as 345 Swill Francs, which equates to around £225 or $360 (US). I don't know about others, but that as waaaaay too much for me to consider, unless it can do something amazing that UIRT can't do. :-[

If you add the cost of the MD and the TV, it becomes a very expensive installation when the practical benefit is actually quite limited (as far as I can see).

Please tell me that either the price is wrong, or I'm missing something here (or preferably both!)
Paul
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posde

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Re: hdmi cec
« Reply #23 on: January 20, 2011, 06:14:05 pm »
wierdbeard65,

it is not a cheap thing, but if it works for multiple devices it is comparable to GC-100. And I prefer to not have a flaky IR connection.

wierdbeard65

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Re: hdmi cec
« Reply #24 on: January 20, 2011, 06:16:25 pm »
if it works for multiple devices
It only has 1 HDMI pass-through, so one would be needed for each TV/MD combo, wouldn't it?

I'm sure there are those that can, and will, justify the expense. Sadly, I can't  :'(
Paul
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totallymaxed

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Re: hdmi cec
« Reply #25 on: January 20, 2011, 10:03:13 pm »
wierdbeard65,

it is not a cheap thing, but if it works for multiple devices it is comparable to GC-100. And I prefer to not have a flaky IR connection.

I'm afraid its one per TV...not really viable at that price.

Andrew
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posde

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Re: hdmi cec
« Reply #26 on: January 21, 2011, 09:21:10 am »
I don't know enough about HDMI-CEC, but from what I've gathered, you need one "control point", in the HDMI chain, i.e. for example between MD and AV receiver, which would control both, the AV receiver and any equipment behind the receiver.

totallymaxed

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Re: hdmi cec
« Reply #27 on: January 21, 2011, 12:21:27 pm »
I don't know enough about HDMI-CEC, but from what I've gathered, you need one "control point", in the HDMI chain, i.e. for example between MD and AV receiver, which would control both, the AV receiver and any equipment behind the receiver.

Yep...thats what I meant. One per display and anything in the chain to it. The problems comes when you have another HDMI 'chain' on another input of say a Home Theatre surround amp... as far as I know you will need a separate HDMI-CEC for each chain of devices (Pioneer Amps definitely work like this at the moment).

Andrew
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Build your system on the latest Ubuntu LTS OS Release!

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posde

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Re: hdmi cec
« Reply #28 on: January 21, 2011, 12:23:58 pm »
Let's see if kwikwai.phil has anything to say to this :)

kwikwai.phil

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Re: hdmi cec
« Reply #29 on: January 21, 2011, 01:47:28 pm »
Here I am.

CEC is a bus so one kwikwai is enough for all components in the HDMI tree (TV, receiver, blue ray, ...).
However, as specified by the standard, the tree has a single device at the top (the TV), so yes in theory you'd need one kwikwai per TV.
But it may work anyway in practice with several TVs according to the use case. For instance, switching off several TVs may be possible.

For the price, we're just starting and our volumes are low. Plus we're providing a complete solution that is installed and working in minutes.
So the moment, the price remains 345 CHF, available immediately in glorious red :)
That said, we'd happy to heavily discount one device for anybody with the time, inclination and competence to build a driver as suggested above. Interested parties, please contact us directly (via PM or email).

Regards,
Philippe