[wsfii-discuss] Re: wsfii-discuss Digest, Vol 23, Issue 13

[Dave Hughes]

Just for your general information, the requirement for about 360kbps
bi-directional for full motion video and video computer conferencing is the
lower threshold usually cited as the minimum needed. 

I am not sure of their numbers, but Skype sure has a working video
capability built into their free computer to computer free connectivity. And
I know it does not take great bandwidth.

As for what could be used in developing countries for tele medicine, don't
lose sight of the tradeoffs of video size, degree of interactivity, speed of
display, and colors over the net. I realize that doctors might prefer always
to have big screen, full speed, full motion video, full color displays -
which would take big pipes (but I assure you there are few enough networks
even in the US who could sustain 20mbps).

The smaller the image on the screen, the fewer bits required. Skype does a
nice job delivering full color, interactive images (both faces seen at once)
About 2 by 3 inches on a side. Sending an image, like a still picture of
part of a body, or xray from one computer to another one way, takes less
bandwith than bi-directional real time. Monochrome takes less than full
color. (I have not seen many color xrays images when I have been xrayed by a
doctor, like my teeth and gums or chest). And a scanned image or jpeg file
from a disk can be 'transferred' one way via Skype even while two people are
in a typing or voice chat, over a number of seconds, or a minute. I could
take my small digital camera, take a still picture of my hand, save it as a
jpeg color, or grayscale, file, and send it to a distant person with whom I
am chatting voice real time, who can pull it up on their screen. And Skype
only requires 36kbps for two way voice.

In other words, the general term 'telemedicine' is too broad. All medical
imaging is not the same, and lots can be done with less bandwidth with a
little thought and planning.   

Dave Hughes
dave at oldcolo.com

-----Original Message-----
From: wsfii-discuss-bounces at lists.okfn.org
[mailto:wsfii-discuss-bounces at lists.okfn.org] On Behalf Of Sudhir Parasuram
(Lakkaraju)
Sent: Sunday, January 21, 2007 7:56 PM
To: Discuss list on the World Summit on Free Information Infrastructure
Subject: Re: [wsfii-discuss] Re: wsfii-discuss Digest, Vol 23, Issue 13

On 1/22/07, l annison <l.annison at gmail.com> wrote:
> > >
> > A project planning to provide e-health services claims that 33 Kbps
> > connection speeds are adequate to transmit live video.
> [...]
> 33kbps is nowhere near enough. I was recently speaking to a doctor looking
> at telemedicine needs and he reckoned that to deliver an optimal service
> 20Mbps was required. However, there are ways to deliver services such as
> video conferencing and webcasts over much lower bandwidths if the right
> codecs etc are used. 33kbps isn't really enough even to deliver good voice
> eg VoIP etc.

20Mbps ? Is the number right ?

20Mbps for video sounds overkill. IIRC, HD-TV usually is anywhere
between 2-4Mbps for video-conferencing.

Regular streaming video of decent quality takes a lot less more (think
two different class of apps - live traffic - yahoo-im/skype/...,
canned-content - you-tube/google-video/yahoo-video/...).

While I certainly don't know the specifics of tele-medicine, 20Mbps
for video apps will never-ever fly in the near future (more so in
evolving/emerging countries).

Cheers,
Sudhir

-- 
Personal blog:
http://sudhir-lp.blogspot.com | http://humor-sudhir-lp.blogspot.com
Social Network: http://www.linkedin.com/in/sudhirlp

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