I got many e-mails from people who want to use A13-OLinuXino as home multimedia center and intend to port different media players on it. All they ask can Olimex add HDMI to this board???
I did a little research and actually there are cheap HDMI transceivers which could take the LCD-RGB signals and convert them to HDMI.
One of these ICs is SIL9022A for instance, it seems perfect and we could easily build HDMI shield with it which to connects to the GPIO connector where the LCD signals are present and to make easy connection with HDMI TVs and other appliances.
Silicon Image, the company which produce SIL9022A is very skinny on datasheet and info for this IC though.
I did request info about it and this is what I got as reply:
To provide you with the requested data it is essential to get more detailed information regarding your project.
The whole documentation is under NDA. Please find attached the NDA-Request. Please fill out very carefully.
The most important information are those of the project. After receiving the filled NDA-Request will we forward it to the manufacturer who will generate the data and the agreement.
For using the requested ICs is it binding to be a HDMI licensee. This licensing is related to a yearly fee of 10.000US$ for HDMI-Membership.
The procedure will be directly executed by the HDMI organization. Further information can be found by the help of the following links: http://www.hdmi.org/
So if we have to build the HDMI shield we will have to pay $10 000 yearly fee to may buy the chips 
For A10 processor which have build-in HDMI I guess this licensee is paid by the SoC vendor i.e. Allwinner, as there is no requirement to have HDMI membership in order to buy these processors and make something with them.
So we may drop the idea for HDMI output for A13 and leave the HDMI output for the next A10-OLinuXino which we will develop after we finish with A13 
EDIT-18.05.2012:
After posting this article I did some more search for HDMI transcievers, TDA9981 seems to be similar to SIL9022A and about same price (well a little bit up) but the datasheet is free to download, so I upload on OLinuXino GitHub repostory and we are about to make one prototype and test if it works correctly, then prepare the A13-HDMI-SHIELD.
I’m still puzzled why Silicone Image have this weird policy to not allow development with their IC if you first do not pay HDMI organization membership, this stops all small volume projects for sure, but it’t their choice, fortunately for us there are also Analog Devices, NXP and many others who offer similar solutions.
EDIT 21.05.2012:
I’m just looking CH7009B datasheets http://www.chrontel.com/products/7009.htm
it have both DVI and analog RGB video, so will be possible to implement both HDMI without sound (as DVI and HDMI encoding is same) + VGA with one single chip
This may be the best approach as DVI have no royalties, and we will be able to make resolutions 1980x1080p via DVI and 1024x768p by VGA
http://www.nxp.com/applications/portable-devices/hdmi-interface.html
Strange I would assume those $10000 are just included in the IC.
There is also the adv7526 from Analog Devices that looks quite simple to interface
They say $3.43 for 1000 and all the info is available without NDA…
ooops i take that back, they do want to sign a NDA, sorry !
Just a thought – have you considered side-stepping the problem by using a different interface, like DisplayPort (something like STDP4028 perhaps)?
how many home TVs have display port input?
I was of course going for DisplayPort as a way to avoid royalties, not as a means of its own; one would presumably use it with a DP to HDMI converter – the more expensive kind, not the cheap ones that are only level adaptors.
On the other hand, if one could find a chip that features DP++, even a cheap passive adapter would do:
“The DisplayPort signal is not compatible with DVI or HDMI. However, dual-mode DisplayPorts (marked with a DP++ logo) are designed to transmit a single-link DVI or HDMI signal across the interface through the use of an external passive adapter that selects the desired signal.” (wikipedia)
You might also want to take a look at Texas Instruments’ TFP410 which is a “PanelBus” DVI transmitter, but DVI works just fine with HDMI cables as well. 24-bit RGB in with H/VSYNC and PCLK and you’re done.
http://www.ti.com/lit/ds/symlink/tfp410.pdf
It is sad that HDMI for small scale projects is financially impossible – see below. Please correct me in the comments if you have different information….
Doing HDMI while fully complying with the licensing terms means that you either have to have a low-volume-high-margin product, or a low-cost-high-volume product (10k units / year would give roughly a cost of $2 per unit first year, falling to $1 subsequent years…).
The gist: You have to pay $10000 / year (“HDMI adopter”) plus a royalty per unit ($0.05 if you display the HDMI logo everywhere, $0.04
if you implement HDCP). A “low volume” plan exists which means $5000 per year + $1 / unit in administrative fees + the aformentioned royalty.
In addition to the above you also have to send your first HDMi product of each class (sink, source, sink+source, etc) to an Authorized Testing Center – cost $7500 if it passes, and extra costs for each re-test.
AFAIK the chip manufacturers pays licenses to the HDMI consortium too, but that does not affect anyone using the chips in their products – anyone releasing a HDMI product (even if it is built from properly licensed parts) have to become an HDMI adopter and pay royalties.
More reading at
http://www.hdmi.org/manufacturer/terms.aspx
http://www.hdmi.org/download/CDF/Licensed_ProductCBP.pdf
http://www.hdmi.org/manufacturer/adopter_registration.aspx
DisplayPort has no royalties, but there are still yearly fees (a couple of thousand dollars), and you still have to test your products and present the results.
Anyone know how DVI works (I believe similar to HDMI, but have not checked).
Video stream is identical in DVI and HDMI, but in HDMI there are additional streams like control (CEC) and multichannel audio. DVI to HDMI and back is possible with a dumb mechanical adapter.
Maybe for Olimex the best move is to include a DVI connector and avoid licensing issues? The user could then buy a simple DVI-to-HDMI adapter to use with TV or just use the DVI if the display is a computer monitor.
Yes, it appears DVI is royalty free, but you still have to sign an “Adoptor’s agreement” and pay $2500 anually. You need to become an adoptor at the latest 12 months after you first put products on the market. See adoptor’s agreement and DVI specification at http://www.ddwg.org/downloads.asp.
Still, it is definitely viable for a 1k unit run, and possibly even for a 100 unit run if the unit cost is high enough to cover an additonal licensing fee for DVI at $25 per unit.
Again, if someone feels this is incorrect, please leave a comment…
I’m just looking CH7009B datasheets http://www.chrontel.com/products/7009.htm
it have both DVI and analog RGB video, so will be possible to implement both HDMI without sound (as DVI and HDMI encoding is same) + VGA with one single chip
All the information seems to be talking about HDMI out.
As some of these chips are transceivers, HDMI input would be a very useful feature for projects I am working on.
Just get a NeTV, you get HDMI in, HDMI out, a powerful FPGA and a Marvell 800 MHz CPU.
https://www.adafruit.com/products/609
http://wiki.chumby.com/index.php/What_is_NeTV