|
|
 
|
Categories
Community Discussion
Ask Away...
RE: The Benefits of using ISDN, ADSL and Broadband
|
Author:
MikeC http://www.touchwoodmedia.com
|
|
Text:
Hi David
Although ISDN has been the standard for remote 2-way studio/audio connectivity for many years, there are now solutions appearing that will allow this to happen via ADSL, DSL and cable modem (IP based technologies). If you think in terms of ISDN, ADSL/DSL and cable modems as the means to connect the studio and the CODEC as the means to COde/DECode the audio then it might be clearer. Unfortunately, the technologies are different (eg. ISDN is synchronous and cable modem is asynchronous) so cross connecting them is difficult. I'm not aware of any products that will do this to the appropriate MPEG audio standards. I also suspect the conversion (encode/decode) would introduce unacceptable latencies over and above the existing code delays. So as you point out, it has to be cable-cable (or another high speed internet connection) or isdn-isdn. There are video conferencing systems like the Encounter 3000 NetGate that supports mixed ISDN/IP communication but I'm not aware of any studio quality audio codecs that will allow this.
To answer your second question, the CODEC provides a two-way/bi-directional audio connection between each facility using the ISDN/IP link. Each studio has to run a compatible codec, ie. one that is able to talk to the other. This sometimes causes grief when they aren't compatible. In this way, it's possible for the studio and the remote voiceover talent (or musician) to talk to each other. There are a number of encoding options you'll hear discussed, eg. MPEG2, MPEG3 (or really MPEG2 layer 3), G722, G711. Each of these offers different audio quality standards proportional to the amount of data that needs to be sent down the line. Most modern codec's allow different compression standards for each leg of the connection, eg. High quality MPEG3 for talent to studio and lower quality G722 for studio to talent. With something like ADSL where the upload bandwidth is limited, this is ideal as you really only need telephone quality for talkback.
I hope that helps,
Mike
MikeC@touchwoodmedia.com
> Hi
> Wonder if you'd mind expanding on this a little. Is ISDN
> the ony system with which real-time sessions be done? If
> not, what are the relative merits of the 3 different
> systems? Can ISDN only 'talk' to ISDN, ASDL to ASDL etc?
>
> Can you offer any advice on CODECs and their use?
>
> Many thanks
> >
> >
>
>
|
Message threads
| Topic: |
Author: |
Time: |
|
|
|
Mark Croasdale
|
24.03.2003 16:28
|
|
|
|
Support Team
|
27.03.2003 16:10
|
|
|
|
David Hale
|
11.04.2003 18:55
|
|
|
|
MikeC http://www.touchwoodmedia.com
|
01.05.2003 12:12
|
|
|
|
|
|
