This is from the textbook. I don't know anything else, so I am posting my question here. These are from Fundamentals of Multimedia by Ze-Nian Li, Mark S. Drew, and Jiangchuan Liu, Third Edition, from Chapter 10 (please answer all questions).
1. Describe how H.261 deals with temporal and spatial redundancies in a video.
2. An H.261 video has the three color channels Y, Cr, and Cb. Should MVs be computed for each channel and then transmitted? Justify your answer. If not, which channel should be used for motion compensation?
3. Thinking about my large collection of JPEG images (of my family taken in various locales), I decide to unify them and make them more accessible by simply combining them into a big H.261-compressed file. My reasoning is that I can simply use a viewer to step through the file, making a cohesive whole out of my collection. Comment on the utility of this idea, in terms of the compression ratio achievable for the set of images.
6. The logarithmic MV search method is suboptimal, in that it relies on continuity in the residual frame.
(a) Explain why that assumption is necessary and offer a justification for it.
(b) Give an example where this assumption fails.
(c) Does the hierarchical search method suffer from suboptimality too?
9. Discuss how the advanced prediction mode in H.263 achieves better compression.
10. In H.263 motion estimation, the median of the motion vectors from three preceding macroblocks (see Fig. 10.11a) is used as a prediction for the current macroblock. It can be argued that the median may not necessarily reflect the best prediction. Describe some possible improvements on the current method.
11. H.263+ allows independent forward MVs for B-frames in a PB-frame. Compared to H.263 in PB-mode, what are the trade-offs? What is the point in having PB joint coding if B-frames have independent motion vectors?
You can read the textbook.