
Compression 111
FIGURE 4.8: Left: original image. Middle: JPEG compression, 100:1 ratio.
Right: JPEG2000 compression, 100:1 ratio. Images from [151].
in fact the approach used in practice by many consumer camera models that
record in MJPG (motion-JPEG), and by some high-end digital cinema cam-
eras that compress each frame using the wavelet transform. But if we take into
account the large temporal redundancy present in most video sequences, we
can achieve significantly higher compression rates. Instead of coding a whole
frame, we can code only the differences with respect to the preceding frame:
as we argued in section 4.2, by their very same nature