G.722 H.320 G.728 etc..

[Gandalf]

Please excuse my ignorance here folks. I'm an A/V guy and this VC stuff is still pretty new to me. I bow before your wisdom. Doesn't look to busy in here yet but hopefully someone will come along and help me out. What I've got is, my compay is looking at getting into the videoconferencing game to cut costs on inter-office travel. The thing is, because I'm an A/V guy they think I automagically know all there is to know about VC stuff as well. We've gone out and purchased a tandberg 2500 and some wonderful SBC network guys came out and installed our ISDN lines. Now my question is that our bridging service provider has provided us with a form to fill out to request VC schedules.

Well there are some funny numbers ane letters next to check boxes for me to select like G.711 and CIF QCIF, etc. I have no idea which ones to select and I need to get some multipoint tests done by next week Monday. If anyone can help me to decipher these I'd very much appreciate it.

[George]

Hi Gandalf,

Welcome to the forums.

Well firstly it would help to know what speed you plan on connecting at because some standards tend to fit different speeds better. For example, let's say you only plan on connecting at 128K bonded :rolleyes: over ISDN as you've said you have ISDN lines. Your choices for audio would be G.711 G.722 & G.728 which are all means of audio encoding. By the way H.320 is just your overall standards set for video and audio over ISDN which is what you use.

G.722 is 7kz sample hifi voice audio. Which is pretty much what you want if you're an audiophile or your participants are more concerned with good audio than anything else. In fact, if you have the bandwidth, 384K or better, I'd suggest you select G.722. The only problem is that it eats up 64K of your bandwidth. So if you're connecting at 128k you just lost half of your connection speed to audio leaving only 64k for video [ouch].

G.711 is the mandatory minimum standard for all ISDN terminal equipment It's basically phone quality audio but uses 64k of bandwidth as well.

G.728 is speech audio which of course implies that if you plan to send anything other than your participants jabbering, this may not be the audio encoding you want to select. The good news about it though is that it only uses 16k of bandwidth.

I generally tend to stick with either G.722 or G.728 depending on my connection speed. CIF and QCIF are your video resolutions supported by H.261 and H.263 which are both supported by H.320 which is what you are running. (In english: You can use either one).

Again, it's a matter of bandwidth availability. QCIF is only a quarter the resolution of CIF (another way of saying FCIF or Full CIF) CIF stands for Common Intermediate Format.

QCIF is used in most desktop videoconferencing applications where head and shoulder pictures are sent from desk to desk. It's better suited for applications like desktop videophones. In your case, I'd imagine CIF or FCIF would be better suited for your needs.

Hope this all helped some.

:D

[Gandalf]

Thanks a million George. That cleared a lot of things up for me. I'll come back here and let you know how it goes!

[pbraatelien]

Gandalf,
I saw your question and reply back by George and just want to let you know a couple of things. Your Tandberg unit will support just about every standard the Bridge service could throw at you. They should (here is my soapbox) be asking you your video type and software rev and they could figure it out for themselves.

As a sales person for videoconferencing, I have always been disappointed in the number of convoluted algorithms that video has grown up with. Can you imagine if you needed all that information before you could make a phone call? Or send a FAX? Or buy a cellphone? It is truly ridiculous. That may be why video has not been accepted as fast as the manufacturers would like.

OK-I am off my soapbox now. Welcome to the forum and good luck!
Paul

[TheAbyss]

I agree with pbraatelien, (what a name lol)

Your provider should be asking you for your specs, and even then only once. They should keep that info in a profile for you and since they're the "experts" they should decide what standards to connect you with, given your specs and your distant ends'.

pb, are you an authorized reseller or something? I saw your other post about having a system in your home on your broadband connection. That must be way cool. Do you use it to test with clients or just personal use? Do you have a website? Always looking for good deals ;)

[pbraatelien]

TheAbyss,
That IS my real name-its Norwegian-no laughing. Unlike your name which I hope to never cross over. Yes, I work for a reseller, which shall remain nameless. I use my video system for both work (demo's and test site for customers) and to talk to a few friends that I know in the business that also have video (not webcams or anything low end).
I have discovered that I can do very effective video at 192K, I just wish that my older Polycom system would someday support H.264 (it won't). I do not have a website other than my personal one for my kids and my hobbies (or were you referring to my work website-www.wireone.com-ooops damn I think I gave it away)
Take care.
Paul

[mazzarak]

Really the idea of numerous numbers of algorithms is no different to buying the latest camcorder with MiniDV, Digital8, and all that stuff. The fact is they had to create these standards to, well, standardise, and because new standards arise, you have to call them something else.

The next stage is going beyond G722 to further compress the audio, so you'll have another one to worry about. It's just one of those things I've got used to.

Going back to Gandalf, if it were me you were talking to, I wouldn't be too concerned if you didn't know what the equipment can or can't do, it's my job as a provider to help you find out. It would be a rather unflexible approach to not just be happy with knowing who you are, where you are, and what your numbers were.

[Gandalf]

Hey thanks a bunch guys. After your sort of pep talk here I was encouraged to just call those guys and used pretty much your words to explain why they should be telling me what to put in the blanks. The technician was very helpful and worked with me on the form. To make a long story short, they now have a profile on file for my site and the distant end so all I have to do is provide the profile ID when requesting a conference and update it when we get new equipment. All I had to do was ask!

thanks again, you guys are great.

[Syed-Ali]

I would like to know about MIC. in Polycom.

Can we use the Polycom MIC with other device?
same :
can we use other MIC with Polycom VS.
Rgds,

[Syed-Ali]

What is the relation with the Television display resolution and Frames / sec..???

Also,
people with the Video Conferancing , if possible send the contact details so that if required we can takl to each other...

[mazzarak]

I believe that some of the users here are putting together a database for VC equipment that we can get together on.

Look out for further updates on this very soon. Possibly. ;)