Stereo RGB Digital video sender

I'd personally like to see devices that sent video over mains cables in
a similar way to the homeplug network adapters I recently bought to
replace my flaky 802.11g network.

That's a good idea. We're waiting for a manufacturer to realise the
potential of using wi-fi links for video without PCs. You can send digital
video all around the house wirelessly today (or use network over mains), but
it has to go through a PC which kills the picture quality.

PCs don't have RGB inputs, and PC satellite tuners don't work for Sky
subscription channels, so everything has to go in PAL (or NTSC), so that's
no good for starters. They rescale the picture, reducing the definition, and
won't do high motion, aside from all the complication of setting them up.

What we need are network adapters with SCART sockets. They should have
hardware mpeg encoder/decoders set at 9 Mbit/s, for picture quality equal to
DVD movies, or DVD recordings in "HQ" mode. It's no more than what's inside
a DVD Recorder, so it should be no more expensive.

The Video Network Adapters would run completely independently of your PC's
router, like a second wireless network. This should present no problems
because wi-fi is designed to share the 100 Mbit/s of radio spectrum capacity
with multiple networks, like it shares with your next door neighbours'
router.

"Stephen" wrote in message
...
I'd personally like to see devices that sent video over mains cables in
a similar way to the homeplug network adapters I recently bought to
replace my flaky 802.11g network.

That's a good idea. We're waiting for a manufacturer to realise the
potential of using wi-fi links for video without PCs. You can send digital
video all around the house wirelessly today (or use network over mains),
but
it has to go through a PC which kills the picture quality.

PCs don't have RGB inputs, and PC satellite tuners don't work for Sky
subscription channels, so everything has to go in PAL (or NTSC), so that's
no good for starters. They rescale the picture, reducing the definition,
and
won't do high motion, aside from all the complication of setting them up.

What we need are network adapters with SCART sockets. They should have
hardware mpeg encoder/decoders set at 9 Mbit/s, for picture quality equal
to
DVD movies, or DVD recordings in "HQ" mode. It's no more than what's
inside
a DVD Recorder, so it should be no more expensive.

The Video Network Adapters would run completely independently of your PC's
router, like a second wireless network. This should present no problems
because wi-fi is designed to share the 100 Mbit/s of radio spectrum
capacity

The claim that wi-fi is capable of 100/108 Mbps is deliberately misleading
as are the claims it makes about its range.

First of all the specification of wi-fi is based on an EPR of 1W whereas in
the EU and US you are only permitted to use 0.1W maximum.

Secondly 802.11g can only run at 108Mbps using compression and even 54Mbps
uses a degree of compression which means that the maximum continuous
throughput you can possibly get through it if you try to transfer an MPEG
file (which is already compressed and which uses a packed bitstream) is
about 12Mbps, and this is assuming that you are within 2 meters of the
network router without any brick walls in the way. Bring in a brick wall you
would be lucky to get 5Mbps in the next room under full load and 2Mbps 6
meters away though more than one brick wall and a wooden floor and that's
your maximum range for 802.11g. Even the 802.11n routers are barley any
better. To get 270/300 Mbps they use two independent channels (for example 6
and 8) and use even more compression. The maximum throughput at a distance
of 2m from the router is only 38Mbps which drops to 12Mbps at 6 meters away
on a good day using MIMO. On top of that g and n are totally incompatible
since n uses two channels at once, so you can't connect a g device to an n
router unless you set the router to g which reduces your bandwidth to 2Mbps
over any meaningful distance.

The tests I have carried out show that with 802.11n you can stream a 4Mbps
DivX/Xvid file over 6 meters with no break-up.

with multiple networks, like it shares with your next door neighbours'
router.

"Paul Martin" wrote in message
...
In article ,
Agamemnon wrote:

Secondly 802.11g can only run at 108Mbps using compression and even
54Mbps uses a degree of compression which means that the maximum
continuous throughput you can possibly get through it if you try to
transfer an MPEG file (which is already compressed and which uses a
packed bitstream) is about 12Mbps, and this is assuming that you are
within 2 meters of the network router without any brick walls in the way.
Bring in a brick wall you would be lucky to get 5Mbps in the next room
under full load and 2Mbps 6 meters away though more than one brick wall
and a wooden floor and that's your maximum range for 802.11g.

The 54Mbps is uncompressed. However, it's never possible to achieve
that continuously, as the signalling is half duplex and not continuous.
Also, your wireless adapter and the base station often continuously
reassess the link's viability and adjust the link speed accordingly.

I regularly get 3Mbyte per second (12Mbit/s) through brick walls.
But then I don't have a 2.4Gbps video sender operating, nor do I have
an Xbox360. (Both use the same waveband and dramatically affect the
viability of an 802.11g wireless network.)

It sounds like my original idea (in a previous thread) of adapting a 2.4GHz
video sender for mpeg was better. Video senders deliver a pretty reliable
analogue bandwidth of 5 MHz to any part of the average house. If you used
one with a digital bitstream on the video input jack they would deliver an
equally reliable 10 Mbps. That's good enough for DVD quality video, and
avoids all the complexity and expense of a multimedia wireless network. They
should make video senders with a hardware mpeg encoder inside, and a
complementary receiver unit with a hardware mpeg decoder.

The mpeg encoder chips are now standard in consumer items like the £70
"Dazzle Video Creator Platinum", and the mpeg decoder chips are inside any
£20 DVD player from Superdrug, so it should not be prohibitively
expensive to make digital video senders this way.