[mythtv-users] HDMI over IP

[Allen Edwards]

The interesting thing is that it says you can feed multiple displays.
That isn't in the DHCP spec and one wonders if all the displays have
to be DHCP or if only one does.  Maybe I am not clear.  The source is
going to insist that there is a valid HDMI display device before it
sends anything out.  If there are 10 displays, there isn't anything in
the spec that I know of that allows this.  If the source is only
looking for one valid device, then do the others just work?  What
about displays that insist on valid HDMI sources?  Will they all get
the word that the source is DHCP?  In other words, the spec is set up
for a handshake between source and display.  How do you shake hands
with 10 displays at once.

I had a non HDMI projector and a HDMI DVD player.  I had this DHCP
compliant splitter/amplifier that would handshake with the source and
everything worked.  As there was no splitter in the spec, they just
had the splitter do the handshake and passed the data to both outputs.
 Everything worked fine until I got a new display that was HDMI
compliant and it wouldn't display because the splitter would not
handshake with the display, just the source.  Now I have this
wonderful splitter/amplifier that I used to drive my very long HDMI
cable which no longer works.  I also have to turn on the projector
before the DVD player or nothing works.  I hate copy protection.  It
is a pain in the butt.

Allen


On Wed, Sep 16, 2009 at 5:27 AM, Michelle Dupuis <support at ocg.ca> wrote:
> So long as they leave the IP payload encrypted (per HDCP) then there is
> little risk...tapping into an HDMI data stream isn't hard.  Decrypting the
> payload is.
>
> -----Original Message-----
> From: mythtv-users-bounces at mythtv.org
> [mailto:mythtv-users-bounces at mythtv.org] On Behalf Of Mike Perkins
> Sent: Wednesday, September 16, 2009 7:47 AM
> To: Myth TV Users List
> Subject: Re: [mythtv-users] HDMI over IP
>
> Nick Rout wrote:
>> On Wed, Sep 16, 2009 at 2:43 PM, Allen Edwards
>> <allen.p.edwards at gmail.com> wrote:
>>> On Tue, Sep 15, 2009 at 7:40 PM, Nick Rout <nick.rout at gmail.com> wrote:
>>>> On Wed, Sep 16, 2009 at 2:24 PM, Jean-Yves Avenard <jyavenard at gmail.com>
> wrote:
>>>>> 2009/9/16 Fa <fayoeu at gmail.com>:
>>>>>> Just thought the people on this list might be interested in this
>>>>>> new product...  I am not endorsing it, I just think it is an
>>>>>> interesting product.
>>>>>> http://justaddpower.com/VBS-Suite-for-High-Definition/82-HDMI-over
>>>>>> -IP-Transmitter/flypage.tpl.html?pop=0
>>>>>>
>>>>> How can they reliably transfer a 2.25Gbit/s signal on a 100Mbit/s link
> ?
>>>> There is a transmitter and a receiver. They must be doing something
>>>> to the stream. The pdf datasheet says "AV  signals  are transmitted
>>>> digitally over the CAT5/6/7 cable without any signal loss. Internal
>>>> JPEG  video  compression  adapts  to available network bandwidth  if
>>>> needed."
>>>>
>>>> Whatever that means, the second sentence seems to imply some
>>>> processing/compression.
>>>> _
>>> It sounds like they are just using Cat5 cable and not an IP protocol.
>>
>> Yes it does, but their own advertising specifically disclaims that, eg:
>>
>> "Not an HDMI Balun, but an HDMI over IP system. This means you can
>> create your own A/V Ethernet network and all of the recievers will
>> find the transmitter automatically. It may even be used over smaller
>> existing house networks and low cost LAN switches and routers."
>>
> Doesn't this break one of the basic tents of HDMI? I thought that the signal
> path had to be secure from end to end, so that no 'pyrates' could tap the
> signal and make off with their precious IP?
>
> If you turn the signal into genuine TCP/IP (as opposed to the other sort of
> IP) then anyone can leech the signal and figure out how it all works.
>
> --
>
> Mike Perkins
>
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