Wireless HDMI

[sleah]

Not entirely theatre relate, but could easily be. I'm just looking for comments and real-world experience / recommendations.

 

Does anyone have experience of wireless HDMI (ideally PC > Projector), in particular hardware only versions rather than those software and/or usb dongle types?

 

We're looking at connecting a lecturn with built-in PC and touchscreen to connect wirelessly to the projector. I've played with a software solution that uses wifi (infrastructure or ad-hoc) and found it pretty darn nasty. I don't know how they can be passed-off as fit for purpose.

I've got a usb dongle based wireless vga system, which although more reliable still can't handle video or fast moving death-by-powerpoint graphics.

 

We've got a hardware solution that uses powerline (we want power to be the only cable to the lecturn) to transmit which so far is the better solution, it will play video and graphics look fine, but there is a noticeable delay especially when mirroring.

 

I guess it's obvious the more you spend, the better it gets, but does a system exist with no noticeable delay?

My boss doesn't want to spend mega bucks (a couple of 100 quid seems about the budget) so wondered if we have found the best there is in that budget range or maybe we have missed something?

[ddproduction]

If you're having one cable anyway, why not loom mains/ethernet/video together in a nice sheath?

[paulears]

I've been using Nyrius Aries pro recently - between a roving camera and the technical position nearly 50m from the stage area - and it was rock solid and decent quality. plugged into the camera's HDMI output, the other end has HDMI out and is pretty much plug and play. I did NOT expect it to do the job very well at all, but it really was impressive.I'll certainly use this again if given the same job to do. It uses USB power at the transmitter end, and the receiver has a wall wart PSU.

[sleah]

If you're having one cable anyway, why not loom mains/ethernet/video together in a nice sheath?

 

Excellent question.

Partly to remove as much cable as possible.

Partly to make it as simple as possible for errr... 'people' to move it between locations (unplug & replug)

And partly to avoid having to run additional cables (be they HDMI/CAT5) to additional connection points, if we can do 100% wireless except power, then we only need additional 13A sockets - subject to being on the same feed for powerline kit of course ;)

[david.elsbury]

There's a Gefen one that looks very promising- not tested it though and you may need to up your budget or lower your expectations :)

[dbuckley]

Pity you're short of bucks, Clickshare from Barco is fabulous for just plugging in a USB thing to a lappy and having the display onscreen wirelessly. Or using a device, just load an app.

[Joe Fernand]

'I guess it's obvious the more you spend, the better it gets' - no matter how much you spend Wireless HD* is reliably unreliable.

Have you considered a PJ with embedded HDBT - that way all you require is an HDBT Tx + a single CAT cable to the PJ. (that works every time with no limitations on frame rate, or compression or noticeable delay).

Powerline is very dependent on the building infrastructure so moving to a new location may not always work as expected.

Joe

*There is no 'Wireless HDMI' - unless HDMI.org have had a recent change of mind!

[david.elsbury]

Really? So what are the products that transmit HDMI wirelessly, (if there's actually no "wireless HDMI") since you seem to have all the answers :)

 

My sales rep here has told me that he uses this product : http://www.gefen.com/kvm/gtv-whd-1080p-sr.jsp?prod_id=10709 quite happily to transmit HDMI, with no wires between a roving video camera to a switcher for cooking demo shows and the like. Has reported 0 problems...

[Joe Fernand]

'So what are the products that transmit HDMI wirelessly' - they don't!

They compress/manipulate it in one way or another - you won't see an HDMI logo on these units!

There are two or three competing technologies - with various hardware manufacturers lined up behind the chip vendors, none of them are ratified by HDMI.org.

http://www.wirelesshd.org

 

http://www.whdi.org

 

As you say lots of folk will report having a good experience with Wireless HD - many more won't.

Have filled a small skip with unreliable Wireless HD units!

Joe

[david.elsbury]

The replacment unit seems to have the HDMI logo - check at the bottom of the page.

 

http://www.gefen.com/kvm/ext-whd-1080p-sr.jsp?prod_id=26335

 

How sure are you that your information is accurate -and where are you getting it from?

[Joe Fernand]

Hi David

You'll not find Wireless HDMI mentioned on the HDMI.org website.

I haven't ever seen anything which changes their statements from 2008/2010 - http://www.cepro.com/article/licensing_chief_still_no_such_thing_as_wireless_hdmi

Funnily though both CEO's mentioned have gone on to work with 'wireless' Co's.

Ask the Gefen Rep which chip they are using and about HDMI certification.

Wireless works for some but always has the potential to not work and comes with limitations/compromise.

Joe

[paulears]

Can I ask a question here?

 

If I'm understanding it correctly, there is a licensing/standards issue??

 

I've never even heard of the HDMI.org website - I assumed, perhaps now in ignorance that HDMI was just a standard for a protocol to enable interconnection, like Composite, Component, SDI etc? My experience of HDMI is simply that it comes out of one socket, and when plugged into an inout with the right connector, it works. As I said above, I used an HDMI wireless link last week that worked amazingly well, connected with no manual intervention and had perfectly sufficient quality viewed on large screens around the room, and some bigger projected images.

 

Is there some issue with certification? I hadn't been aware that HDMI was not an open protocol like the others?

 

I think you need to enlighten us on a problem that many of us were totally unaware of? I've got two of the Nyrius units here that don't belong to me and was thinking of buying something similar for myself.

 

You said

So what are the products that transmit HDMI wirelessly' - they don't

Er, mine just did - have I missed something important.

 

I assumed the HDMI label was akin to the DVD and CD one - adherence to a standard, but I'm now thinking what you mean is that many devices do not meet the specs, but still work? Am I right?

 

 

Doing a bit of reading seems to suggest that the problem here is that HDMI was designed as a high quality cable based distribution system, so wireless transmission breaks the specification parameters due to the processing required for wireless transmission. In our industry, which is 100% nothing to do with homes or domestic use, we're well used to these sorts of compromises, and have lived with it with analogue and digital for a long time now, and our judgements of 'quality' tend to be based on quite subjective opinion based on our usage. We frequently balance the ultras technical specs against practical one. We have a historically unhappy relationship with the hi-fi world - their aims and needs being quite detached from ours, yet both groups use sound professionally, but our(my) view of them is that so much they aim for is just not audible. Maybe I am looking at HDMI as a connector type only, with our usual issues being aired centred on maximum cable lengths and avoiding the kinds of issues cable problems cause. Having a solid, locked and reliable signal is our main aim. Ultimate image quality comes second. Latency is an annoyance, but for us a fact of life in both audio and video. We rarely get that worried about it.

 

If I have read this correctly, what we are saying is that Wireless links from HDMI equipped equipment is perfectly possible, but that the HDMI specification is not met, end to end - therefore it cannot be licensed or approved my the HDMI community. Are we also saying that any system that does the job but doesn't meet the spec is therefore unable to be recommended? I assume the lack of the HDMI logo doesn't constitute grounds for legal action, as in using the protocol, but not paying for membership?

 

Most of the info on hdmi.org seems to be based on copyright of the logos and registration of adopters. There doesn't seem to be any mention of products fitted with HDMI sockets that are not official adopters. No warnings about dodgy manufacturers meeting the specs?

 

I'm left a bit confused - are we actually talking about protection of a logo, or the system?

[david.elsbury]

I think joe is going on about the logo... I will ask Gefen what their position is and report back...

[sleah]

'I guess it's obvious the more you spend, the better it gets' - no matter how much you spend Wireless HD* is reliably unreliable.

Have you considered a PJ with embedded HDBT - that way all you require is an HDBT Tx + a single CAT cable to the PJ. (that works every time with no limitations on frame rate, or compression or noticeable delay).

Powerline is very dependent on the building infrastructure so moving to a new location may not always work as expected.

Joe

*There is no 'Wireless HDMI' - unless HDMI.org have had a recent change of mind!

I'm afraid you lost me at PJ, nevermind HDBT!

 

That Gefen unit looks promising, and not too expensive either once converted to 'real' money ;) Although postage from th'states could be a killer?

[Shez]

How about "Wireless video sender with HDMI inputs and outputs"? More acceptable than wireless HDMI?