Reference no: EM134030310

Assignment:

1. Give the ASN.1 encoding for the following three integers. Note that ASN.1 integers, like those in XDR, are 32 bits in length. (a) 101. (b) 10,120. (c) 16,909,060. (note that ASN1 int length needs not be 32 bits)

2. Give the big-endian and little-endian representation for the integers from Exercise 7.

3. Different architectures have different conventions on bit order as well as byte order-whether the least significant bit of a byte, for example, is bit 0 or bit 7. RFC 791 defines (in its Appendix B) the standard network bit order. Why is bit order then not relevant to presentation formatting?

4. Compare the size of an all-white image in JPEG format with a "typical" photographic image of the same dimensions. At what stage or stages of the JPEG compression process does the white image become smaller than the photographic image? For the next three exercises, the utilities cjpeg and djpeg may be useful and can be obtained from ftp.uu.net/graphics/jpeg. Other JPEG conversion utilities can also be used. For manual creation and examination of graphics files, the pgm portable grayscale format is recommended; see the Unix pgm(5)/ppm (5) man pages.

5. Suppose we have a video of two white points moving toward each other at a uniform rate against a black background. We encode it via MPEG. In one I frame, the two points are 100 pixels apart; in the next I frame, they have merged. The final point of merger happens to lie at the center of a 16 × 16 macroblock.

(a) Describe how you might optimally encode the Y component of the intervening B (or P) frames.

(b) Now suppose the points are in color and that the color changes slowly as the points move. Describe what the encoding of the U and V values might look like.