Author Topic: HDMI over IP  (Read 2702 times)

dlewis

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HDMI over IP
« on: October 24, 2009, 05:45:00 pm »

totallymaxed

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Re: HDMI over IP
« Reply #1 on: October 25, 2009, 09:39:02 am »
Interesting stuff...

http://www.justaddpower.com/Home-Theater-HDMI-Matrix/View-all-products.html

There are several solutions coming to market that do HDMI over the LAN using managed switches. This allows you to intermix HDMI and all othe IP based traffic on the LAN...at least in 'theory'. The chipsets to enable this are still very new and it is clear that there may still be significant issues...but this is the way of the future for sure. We are planning two installations using this type of technology currently but it will be several months before we know if we can get the reliability levels we need. I'll update the forum when we have some news.

All the best

Andrew
Andy Herron,
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colinjones

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Re: HDMI over IP
« Reply #2 on: October 25, 2009, 10:01:22 pm »
Will be interesting to see the quality of the image that comes out the other end! GigE is nowhere near enough bandwidth to carry a single 1080p stream (~1.5Gbps) so they are capturing the images and compressing them using JPEG2000..

rperre

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Re: HDMI over IP
« Reply #3 on: November 12, 2009, 05:18:03 pm »
I asked them a question about price, and got this answer, i'm posting it here because it pretty much involves the whole setup of the vlan and how to switch ports after the setup. What i really like is the instant switching of sources. I asked them if the prices will come down in the near future, but no answer to that.

Quote
We have had 100% success and reliability with the RS232 control of the Managed Ethernet switches.  Here are the commands we used to initialize the Cisco 2960 for the CEDIA demonstration.  It should be noted that the GUI software we prepared for CEDIA assumed that the 9 screens were attached to ports 1-9 of the switch.  For our purposes, we attached the 5 HDMI sources to the last 5 ports (20-24) of the switch, but you can change this if you like.  Just adjust the VLAN assignments accordingly (this will make sense to you in a few minutes).  NOTE:  The default VLAN for newly activated ports is #1, and we don't recommend using VLAN 1 for HDMI over IP as a precaution to prevent accidental overload of the other LAN devices.

Lets begin!

Start a Windows HyperTerminal session at 9600, N, 8, 1 and point it to the COM port that is attached to the CONSOLE port on the switch.  When you first connect to the RS232 CONSOLE port press enter a couple times to get to the Switch> prompt.  Then issue the following commands (note that the default password on a Cisco switch is 'password').  You press ENTER after each command.  The RS232 GUI software issues the same type of commands to control the switch (with a CRLF after each command).  Comments are placed inside [brackets], and are offered for your edification and are not to be entered.

enable
password
conf t
line con 0
exec-timeout 0
[sets the Cisco console to NEVER timeout, so we don't have to bother with
the password again]
exit
exit
write
[the WRITE command saves your work to the switches memory]

[now lets create some new VLAN's for our 5 HDMI over IP channels - you can use your own names for the channels]
conf t
vlan 2
name Blu-Ray
vlan 3
name Xbox
vlan 4
name Vudu1
vlan 5
name Vudu2
vlan 6
name Camera
exit
exit
write
[now, let’s make sure all 24 of our Ethernet ports are fully enabled]
conf t
int fa0/1
speed 100
switchport mode access
no shutdown
spanning-tree portfast
int fa0/2
speed 100
switchport mode access
no shutdown
spanning-tree portfast
int fa0/3
speed 100
switchport mode access
no shutdown
spanning-tree portfast
......

[Keep up the pattern till all the ports have been enabled]

......

int fa0/23
speed 100
switchport mode access
no shutdown
spanning-tree portfast
int fa0/24
speed 100
switchport mode access
no shutdown
spanning-tree portfast
exit
exit
write

[Now assign 5 ports (we used 20-24 in the demo) to the 5 transmitters, each
on their own VLAN]
conf t
int fa0/20
switchport access vlan 2
int fa0/21
switchport access vlan 3
int fa0/22
switchport access vlan 4
int fa0/23
switchport access vlan 5
int fa0/24
switchport access vlan 6
exit
exit
write
[Done! Your switch is now ready for the GUI Modules already written for Crestron, Control4, and AMX]

Want to know more?  Here is how the GUI's "change channels".

Step 1)  There is an "initialize" option behind the scenes of the GUIs that issues the ENABLE command and the associated password needed to be in "privileged" mode.  This command only needs to be entered when the switch has been power cycled:

enable
password

Step 2)  Select a port, and change its VLAN.  To change port 1 to VLAN channel 4, here are the commands:

conf t
int fa0/1
switchport access vlan 4
exit
exit

To change port 9 to VLAN channel 6, here are the commands:

conf t
int fa0/9
switchport access vlan 6
exit
exit

It is not necessary to issue the WRITE command when changing channels.

Just Add Power

niz23

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Re: HDMI over IP
« Reply #4 on: November 13, 2009, 11:16:07 pm »
This is standard Cisco configuration.
It contain nothing special that a non managed switch should not be able to do.

The only reason they seem to use a managed switch is because they want to keep transmitter and receiver pairs on separate networks.
This can easily be done with a couple of cheap unmanaged switches for each T/R pair and that way keep data traffic physically separated.

The other reason I see is that cheap unmanaged switches tend to differ in quality.

/niz23

nosilla99

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Re: HDMI over IP
« Reply #5 on: November 14, 2009, 03:20:58 am »
Looking at the config, it seems that you change the vlan of the switch port to select which channel you want to watch.

i.e they have 5 video sources connected to vlans 2-6, which are physically coonected to ports fa0/20 through to fa0/24

You then change the vlan port of your connected device to the vlan associated with the channel you want to watch.

So they are obviously using some sort of streaming protocol to deliver the video and audio.

NOS

totallymaxed

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Re: HDMI over IP
« Reply #6 on: November 14, 2009, 03:18:49 pm »
Looking at the config, it seems that you change the vlan of the switch port to select which channel you want to watch.

i.e they have 5 video sources connected to vlans 2-6, which are physically coonected to ports fa0/20 through to fa0/24

You then change the vlan port of your connected device to the vlan associated with the channel you want to watch.

So they are obviously using some sort of streaming protocol to deliver the video and audio.

NOS


Yes they are...and that is why you do not get full HDMI picture quality at the 'receiver' end... these solutions are all compromises currently.

Andrew
Andy Herron,
Convergent Home Technologies Ltd
United Kingdom

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cpszx

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Re: HDMI over IP
« Reply #7 on: November 15, 2009, 11:12:16 pm »
i really dont understand why they only put 100Mb interfaces into the tx/rx pairs on a new product, with multicast video streaming as its function! talk about strangle a new born

1080P@60fps is about 3Gb, 1080p@24 obviously around half, but thats uncompressed pure data.

so even at a very very basic average level of 10:1 image compression, gigabit ethernet would be more than adequate, especially when using multicast streams and dedicated vlans per group.
vlan per source is a well considered solution to get maximum throughput from a switch, assuming the backplane has the capacity

even higher compression would be possible on some source images, which would make 100Mb sustainable in some circumstances

although, they have used jpeg2000 which encodes every single frame, rather than mpeg4 which encodes a reference frame then a series of motion change updates, to try and maintain a level of output quality

mpeg4 has a lower bandwidth requirement on most streams, but images with lots of changes (fast moving full screen action) will often suffer quality problems

jpeg has a better replay quality with full data for every frame but is more sensitive to bandwidth issues.

obviously the average home user would not have vlan and igmp capable managed Gigabit switches to make best use of the technology, but why throttle the product from day one?

they have obviously gambled on predicted higher compression ratios to support average home user hardware, which is a shame.

hadnt considered these options previously, but am going to search for some other vendors now they are breaking onto the market with 1080p

craig

cpszx

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Re: HDMI over IP
« Reply #8 on: November 15, 2009, 11:30:02 pm »
ok, i got curious about it, so did some digging, and found this on a faq entry on a distributor site, in case anyone else was interested....
Craig

http://www.hdcable.co.uk/hdmi-over-ip-receiver.html




How it is possible to deliver full 1080p audio/video to multiple screens with "only" a 100BT Ethernet LAN?

The heaviest bandwidth consumer for HD sources currently is Blu-Ray with a maximum bitrate for Audio+Video+Subtitles set at 48Mbits. All other 1080p sources (HD-DVD, Tivo's, Vudu's, Media Center PC's, Gaming Platforms, Digital Signage content devices, etc) come in well below that bitrate. Most of the time even a Blu-Ray movie is not putting out content at this maximum bitrate (30MB-40MB LAN is the typical bandwidth).

Our HDMI over IP units can use up to 50MB LAN bandwidth for sending 1080p to a single receiver, and up to 60MB LAN bandwidth for sending 1080p to multiple receivers (NB the same multicast bandwidth is consumed whether you are sending to 2 or 200 receivers). Most of the time much less bandwidth is needed (especially for Digital Signage content). The ASIC's on the TX/RX units only use compression/decompression to reduce the bandwidth when necessary due to other network traffic, but not if there is sufficient bandwidth available on the LAN to send the full audio/video data stream. While the formal HDMI specification has much more bandwidth defined, that overhead bandwidth is not needed to send perfect 1080p audio/video sources digitally over a 100MB LAN.

While we are not the first company to figure out how to distribute HDMI over IP, all of our competitor’s solutions require expensive Gigabit 1000BT industrial switches. Our HDMI over IP solution works fine on a standard 100BT LAN (works with everyday value commonly found LinkSys and NetGear switchers/routers).

A 1000BT device will cost well over £1000 per screen to implement, while ours have a retail price of just £200 per receiver.