Re: [Ekiga-list] configuration

[Shawn Adams <shawn_adams web de>]

John,

I suspect  I may be jumping into the middle of a conversation without 
all the information, but wanted to lend my bit into this. Please forgive 
me if I've misunderstood something.

The goal is to send/receive high-quality video over the Internet to 
enable such things as lip-reading.

The problems:

#1 most ISPs only offer 256k upload bandwidth, creating transmission 
issues. some offer higher priced accounts that guarantee higher rates, 
but perhaps at prohibitive costs

#2 ISPs that either ignore, remark, or do not honor DSCP (differential 
Services code Point) markings.

#3 perhaps less than optimal codex for video - theoretically, a more 
efficient codec could be written packing more real video information 
into fewer packets or bytes,  perhaps I'm incorrect here.

The parts I know a litte about are #1 and #2

#1 bandwidth limit at the user's connection

If you are limited to 256k upload bandwidth, and the video you are 
sending is 256k, there might be issues. The fix is to configure the 
sending PC to reserve ALL 256k for the video (based on the source or 
destination IP addresses, UDP/TCP ports). If this is done properly, the 
video would consume all 256k, anything else would have to wait until the 
video transmission was not sending.

#2 Quality of service across the rest of the Internet.

If the sending PC marks video traffic in accordance with networking 
"best practise" for loss and delay sensitive data - like voice and 
video, that's great.

this marks each frame with a number that tells routers along the way to 
give these frames higher priority than say, an HTTP or FTP frame.

Problem is - unless your ISP looks at, and honors these markings - it's 
useless. I think there are ISPs who offer the promise of looking and 
honoring your markings, but these are usually expensive commercial 
contracts for more than one DSL line.

The other larger issue is - that even if the sender's ISP honors the 
markings, - no guarantee that the rest of the internet does. the frames 
might zip through the sender's ISP network, only to be delayed, or 
dropped somewhere else along the line.

I'm sure there are ISPs who give bandwidth guarantees too, but at it's 
price.

Thoughts:

#1 perhaps some ISPs might be willing to offer something like a "hearing 
impaired DSL account" if they know the size of the community, and the 
potential revenue when they are the 1st and only ISP to provide 
end-to-end QOS (quality of service) for such services.

#2 With Linux, you can always try to mark the frames with DSCP, reserve 
the ethernet card bandwidth to ensure video gets 100% of the 256k, and 
see if it works better.

This would be done outside Ekiga with such tools as dsmark and tc

http://lartc.org/
http://www.rns-nis.co.yu/~mps/linux-tc.html
http://opalsoft.net/qos/VoIP.htm

If this sounds at all interesting, I can work up a script for linux, but 
not sure this is a full solution.

Best regards,





John Hawley wrote:
> Thanks very much for your suggestion but minicom and similar text based 
> devices have now been supplanted with sms, and IM both of which are poor 
> substitutes for face to face talking.
>
> The irritating thing is that we have used skype video calling for this 
> purpose for 3 or 4 years (with varying degrees of success) but the trend 
> for ever increasing camera resolution is outstripping bandwidth 
> resulting very good quality pictures but at a transmission rate 
> inadequate for lip-reading purposes. Perhaps I should clarify that by 
> bandwidth, I mean upload bandwidth, whereas download bandwidth has 
> steadily increased over the last few years, (currently because its 
> copper wires into the house its 8Meg), upload bandwidth has remained at 
> 250k thus end to end video is at 250K! UK ISPs appear to have no 
> interest in increasing this number!
>
> What I'm trying to achieve is to force all/most of that available 
> bandwidth into video stream and Ekiga would at least seem to offer that 
> prospect.
>
> It also seems to me that such a configuration, if it could be achieved, 
> would soon have a dedicated fan base amongst the hearing impaired and 
> potentially could attract (although I'm sure you're wary of "sponsors") 
> some funding from the EU or Deaf charities.
>
> Thanks again John H
>
>
>
>
>
>
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