Compression project >> Video Area Home

MSU Perceptual Video Quality tool

Program for counting mean opinion score

MSU Graphics & Media Lab (Video Group)

Project, ideas: Dr. Dmitriy Vatolin
Implementation: Oleg Petrov

Version 1.0 (DSCQS type II added, bugfixing)
Version 0.9 (DSCQS, DSIS and SAMVIQ added, AviSynth support)

“MSU Perceptual Video Quality tool” is a tool for subjective video quality evaluation.
Download!
Information about subjective methods
FAQ
Order now (for companies)

Main features:

Six methods of subjective comparison, four are from the ITU-R BT.500 standard and one was recently submitted for standardization!

DSIS (Double Stimulus Impairment Scale)
DSCQS (Double Stimulus Continuous Quality Scale) type I and type II
SCACJ (Stimulus Comparison Adjectival Categorical Judgement)
EBU SAMVIQ (Subjective Assessment Method for Video Quality evaluation)
MSUCQE (MSU Continuous Quality Evaluation)

Three methods of averaging results.

Supports .avi files and .avs (AviSynth).

Results are saved in simple CSV format.

How to make subjective video quality comparison

There are a lot of ways to carry out subjective comparison. If you want to make comparison on professional level, you should get a standard that describes every detail of it, like ITU-R BT.500 “Methodology for the subjective assessment of the quality of television pictures”.
It includes detailed description of test environment, tests methodologies and results processing.
Subjective comparison usually consists of following steps:

Choose video sequences for testing (they are often named SRC).
Choose settings of systems that you want to compare (often named HRC).
Choose test methodology (how sequences are presented to experts and how their opinion is collected).
Invite sufficient number of experts (not less than 15 are recommended).
Calculate average marks for each HRC based on their opinion.

"MSU Perceptual Video Quality tool" supports 6 different test methodologies and 3 ways of processing results.

How to use this tool

This tool consists of two parts.
First part is "MSU Perceptual Video Quality - task manager". You can use it to create task file and to collect expert's results - just add video files(.avi, .avs) that you want to compare, set amount of tests that you want expert to go through, give name to task (+some additional options) and save the task file.
If you use .avs file, your AviSynth script should return a value, i.e. have string "return clip" at the end of it.
Second part is "MSU Perceptual Video Quality - player". It can play video files from task and record expert's reaction in a way that is defined by task methodology. Expert can run "MSU PVQ - player" and open any task on his or her choice.
It is possible to group any number of tasks, so expert doesn't need to open them. To do this, create .bat file with following contents:

"MSU perceptual video quality player.exe" "c:\tasks\task1.tsk" "c:\tasks\task2.tsk" ...

In addition, it is possible to conduct test for color blindness, just add -c key to the command line:

"MSU perceptual video quality player.exe" -c "c:\tasks\task1.tsk" "c:\tasks\task2.tsk" ...

Results of this test (standard Ishihara charts are used) will be added to results of all tasks that an expert will go through.

Settings

Task manager settings

Name of task - Task name; When expert finishes task, subfolder with name of task is created in folder that contains task file. Results from all experts are stored there. Results for particular expert are stored in file "expert_name".csv.

Amount of tests - Total tests amount. When set to minimum, each file is compared with each other only once. You can increase number of tests, it will allow system to measure expert's reliability (measure of reliability is based on average disperse of answers).

Add/Remove file - Add/Remove file from test list.This tool supports .avi and .avs files. Add only files that can be opened on experts’ computer! It is assumed that all files are different versions of one sequence (for example, compressed with different codecs).

Task type - With this tool you can make six types of subjective comparisons.
See Subjective video quality methods information

Count results - There are three ways of calculating final mark: simple averaging, averaging from ITU-R BT.500 and our own MSU averaging that uses reliability marks for experts. Results from any method that you choose are added to the final file "average_mark.csv".

Other task options - Detailed description of all task options you can find in Help file attached to the program.

When you start "MSU Perceptual Video Quality - player", you need to input your name. Your results will be stored in file "expert_name".csv.

Player controls

Player controls

Playback controls - You can play/pause film, rewind it 3 seconds back, restart current test or whole task (you can disable pause and rewind in task settings). When you cancel test or task your results are discarded.

Give your mark - This is an example of a dialog that asks expert about his or her opinion (from ‘Double Stimulus Impairment Scale‘ test method).