|
standard for compression (synchronized) audio and video
|
|
4 parts: video encoding, audio encoding, "systems" (synchronization) and compliance testing
|
|
defines 352x240 pixels (30 fps in USA, 25fps in Europe)
|
|
MPEG-1- designed for bandwidth up to 1.5 Mbps
|
|
MPEG-2 - higher quality; designed for bandwidth 4-10 Mbps
|
|
MPEG-3 - does not longer exist; MPEG-4 - very low bitrate coding
|
|
DCT (Discrete Cosine Transform ) done on 8x8 blocks
|
|
lossy algorithm with compression in space (DCT) and time (frame to frame)
|
3 types of frames
-
I (Intra) frames - sent every 10-12 frames as still images
-
P (Predicted) frames - deltas from the most recent I or P frame
-
B (Bidirectional) frames - interpolation between I and P frames
|
