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This soft copy for use by IBM employees only.
Table 4. Video Distribution Module Comparison of
Feature |
|
|
|
|
|
| |
System Layer | Provides audio and video | No system layer, that is, | |
| synchronization. | no standard | |
|
|
| synchronization method. |
|
|
|
|
Record on Servers | Yes |
| Must record video and |
|
|
| audio separately, leading |
|
|
| to synchronization |
|
|
| problems. |
|
|
|
|
Motion Compression | Yes |
| No |
|
|
|
|
Standard Auto | Yes |
| No |
Compression |
|
|
|
|
|
|
|
Compression Algorithm | DCT |
| DCT |
|
|
| |
System layer can carry | No | ||
|
| ||
| equipment downward |
| |
| compatible with |
| |
|
|
|
|
Private Data for Closed | Yes |
| No |
Captioning |
|
|
|
|
|
|
|
Bandwidth Requirements |
| Less | 20 Mbps |
for High Quality Video |
| than 18 |
|
|
| Mbps. |
|
| I + P Frame | Less |
|
|
| than 12 |
|
|
| Mbps. |
|
| IPB Frame | Less |
|
|
| than |
|
|
|
| |
|
| Mbps. |
|
|
|
| |
ATM Compatibility | Requires | ||
| Streams can be carried | constant bit rate (AAL1) | |
| over AAL5 and can take | services for accurate | |
| advantage of variable bit | voice and video | |
| rate services. |
| synchronization. |
|
|
| |
Standardization | Video conferencing and | ||
| transmission using | ||
| are standard. | H.310 | |
| encompasses | standardized. | |
| and defines operational | Proprietary | |
| specifications for | implementations cause | |
| over ATM video | interoperability problems. | |
| conferencing. |
|
|
|
|
|
|
4.6.2 Configuring the Video Distribution Module
The Video Distribution Module is a relatively simple module to configure since it is merely a target for an ATM stream from another source. The process is as follows:
•Enable the VDM port as a UNI interface: In the following example:
−The second port of the VDM for our video output is set.