Motion Vector Search Experiments

Homework 2 of the course Video Communication (2018 Spring).

Compile

The source code is under the src/ directory, You can do

$ make build

in terminal to compile the repository.

Execute

The compiled executable is placed at bin/hw2. If you want to apply cross searching algorithm on the video data/Foreman.CIF, just do

$ bin/hw2 data/Foreman.CIF -f CIF -s cross

• -f flag specifies the video format, which can be either CIF or QCIF only.
• -s flag specifies the motion vector searching algorithm. Supported algorithms for now are: three_step, orthogonal, gradient_descent, cross, hexagon

The command above outputs the PSNR values of each frame, compared to its previous one.

Generate Charts

It uses Gnuplot to generate the charts from the outputed logs. You can do

$ sudo apt install gnuplot5-x11

to install this dependency first.

Some scripts in doc/plot can automatically generate charts and logs for each test video and searching algorithm:

# Choose one of the shell scripts to perform
$ bash doc/plot/plot.bash directory/to/test/videos/
$ fish doc/plot/plot.fish directory/to/test/videos/

The second one needed fish the shell to be installed.

The generated logs and charts are put in doc/plot/log and doc/plot/png respectively. Here are the expected charts that generated.

Noted that the greyout area indicates no searching algorithms have applied; that is, all the motion vectors are assumed to be (0, 0). All the searching algorithms are expected to have superior results than merely do nothing.