Total data rate: 1150000 bits/sec=143750 bytes
Audio: 224000bits/sec=28000 bytes
Video: 143750-28000=115750 bytes
This means and average of 115750/25=4630 bytes per frame for video.
If video at that resolution is stored in as uncompressed 24-bit RGB values that would require
For video: 352*288*25*3=7603200 bytes/sec
For audio: 44.1kHz, stereo, 16bit = 44100*2*2=176400 bytes/sec
=7779600 bytes per second in total uncompressed.
This means that the compressed data on VCD takes up a fraction of the uncompressed data.
That gives us a 98.152219% saving!
The problems of VCD such as low capacity i.e. only 66 minutes of video per disc, no subtitles and no interactive capabilities (other than skip forward\backward and pause at the start of chapters) are all fixed by the higher capacity of DVD and extensions to the coding scheme. I think that sub-picture data is used in MPEG for interactive features on DVDs. NOTE: sub-picture data may be stored in some "ancillary data" part of the coding scheme. I'm not sure on the exact details though.
DVD is based on MPEG2 which only adds 16*8 macroblocks to the MPEG1 coding scheme. Better visual quality is available on DVDs because they are generally mastered at much higher resolutions and bitrates made possible because of the "much higher than CD" transfer rate of entry level DVD players.
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