[Klug-general] HDMI over wifi ... ?

[Karl Buckland]

I've looked into this previously, as I want to run HDMI from one room to
another inside my home.

Unfortunately there is no such thing as true wireless HDMI. As Roger
Gammans has noted, the bandwidth requirements are simply too high. Even to
run HDMI over cat5 cable (not a network, but simply the cable) requires two
cat5 cables of good quality. Even then, I've found that depending on the
length of the run, 1080p may not be an option. In my case a 20m run of cat5
cables allows 720p but not 1080p.

There are products out there that claim to enable wireless HDMI. What they
actually do, is convert and compress the HDMI signal and then send it over
TCP/IP or using another proprietary method. Whether or not this is an
acceptable solution for you depends on your requirements. I want to play
movies over the HDMI connection, so ideally I want a good clear
uncompressed signal. If you do go with the wireless route, then the quality
of the resulting picture (and audio) depends on signal strength, so if you
have a lot of other wireless signals in the sane frequency range then that
will cause you problems. I also expect that if you need to go through a
thick church wall, then that might present an issue?

>From what I can see the best results actually come from high quality HDMI
cables (such as those made by BlueRigger), but even there most cables have
problems when they get near the 50m mark. If you need to run anywhere near
that length, then all bets are off, and you'll need to experiment. Also,
before anyone chimes in about 'expensive HDMI cables' - yes it's true that
over short runs (less than a couple of metres) even the cheapest HDMI cable
will be absolutely fine. Over longer runs that simply isn't the case. Even
the smallest signal degradation will bring HDMI to its knees. The higher
quality long-run cables have thicker wires to prevent that signal
degradation over such a distance. You can also find some cables with
'boosters' in them (or buy separate powered boosters separately). I haven't
tried these boosters, So I can't vouch for their effectiveness. My own
setup is now a 15m BlueRigger HDMI cable, which can do 1080p with no issues.

Hopefully this is helpful for you.

Karl


On 18 January 2015 at 12:22, Paul Lawrence <paul.z.lawrence at btinternet.com>
wrote:

> Hi Group
>
> Some advice please.
>
> I've been working with a group to install a giant TV in my local church
> (12th Century and therefore the structure is highly regulated) for
> presentations/videos etc and using maybe Easyworship software to manage
> the displays. The TV is lowered and raised from the roof area as required (which
> required lots of permissions) The arrangement is based on a graphics card
> in the PC that has HDMI out. Distance from PC to TV must be at about 50m which
> we manage using a pair of HDMI over Cat5 boxes. This works pretty well.
>
> Fig1:
>
>  PC&HDMI → Convert to Ethernet → 2xCat5 → Convert to HDMI → TV
> I
> line-out
> I
> V
> sound-desk
>
> Enables us to play the presentation on TV and manage the sound via
> existing sound-desk and sound system.
>
> The Cat5 is proving unreliable (and very untidy) and we've looking at ways
> of using wifi (and currently an AppleTV box) to replicate the above.
>
> Fig 2:
>
>  iMAC/PC → wifi → Airport → wifi → Apple TV → TV
>
> We can use Airport router and Airparrot2 software to send to an Apple TV
> box plugged into the TV HDMI to display the video but no sound comes from
> the PC - all sound is from the TV. An alternative could be a Chrome browser
> to 'cast' the tab to a Chrome dongle but I suspect the same result.
>
>
> 1. Am I right in thinking that when using Airparrot2/Chrome browser the PC
> has no action in decoding the file merely streaming to the TV? And that is
> why we get no sound from PC. Which leads me to think we'll need to connect
> the TV to the sound desk via one of the sound input XLR points.
>
> 2. If we cannot repair/re-run the Cat5 .. is there a (cheap) way of
> sending HDMI over wifi?
>
>
> Thanks
>
>
> Paul
>
> _______________________________________________
> Kent mailing list
> Kent at mailman.lug.org.uk
> https://mailman.lug.org.uk/mailman/listinfo/kent
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.lug.org.uk/pipermail/kent/attachments/20150118/08ffc8d6/attachment.html>