IBM SG24-4817-00 manual Audio Compression, Mpeg Summary

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Figure 19. Typical MEPG-2 Picture Sequence Showing Picture Types

Since the anchor frame is sent only intermittently, and only changes are sent for the intervening frames, significant bandwidth savings can be realized, with minimum degradation of picture quality. It should be noted, however, that response time may be unacceptably affected in some situations when using full IPB compression. This can be remedied by using just I and P frames, resulting in similar delays to M-JPEG but requiring much less bandwidth.

4.6.1.4 Audio Compression

The MPEG-2 system multiplex layer allows for various audio compression standards to be used, and the definition of a standard compression scheme ensures compatibility between vendors. In comparison, M-JPEG does not include an audio standard. Audio is transmitted separately from the video.

4.6.1.5 MPEG Summary

MPEG-2 is superior to M-JPEG because of its ability to multiplex and to synchronize, to interpret motion and to provide improved compression, and to transport multiple different audio compression data streams.

Table 4 on page 52 provides a convenient comparison of the two technologies.

Chapter 4. IBM 8285 ATM Modules 51