SIGGRAPH 97 Networked Video Compression Times and Expenses Speed Codec's designed for point to point video, such as H.320, work quickly but quality is lower Codec's designed for higher quality, have good compression and quality but they take time (100's of milliseconds) Costs for compression / Decompression Codec's for point to point communication require compression and decompressions at both ends so they cost the same at both ends Higher quality codec's (MPEG) - the encoder is expensive, but the decoder is very inexpensive

NOTES:

The technique that MPEG uses to do encoding requires the encoder to look at the images both forward and backward . This holding of reference frames requires both storage and time. The quality of the compression is better than realtime encoders and the quality of the images are maintained, at the cost of realtime. Variation of the MPEG encoding technique can decrease encoding time, without decreasing the image quality. This faster encooding results in higher frame size, requiring more network bandwidth.

Realtime encoding allows for higher loss of image quality to achieve a small frame size and the ability to encode in near realtime.