VQLab Results Viewer – Multiple Views of Video Quality
In order to be efficiently analyzed, understood and communicated information needs to be organized and displayed in a way that increases readability. Access to necessary details or synthesis must be fast and easy. After you perform a video quality test VQLab’s comprehensive Results Viewer offers you several views of the quality, easing the task of understanding and sharing the results. You can either view statistics about the overall quality of your processed videos or have an in depth view of the quality for each frame. Graphical representations of the results allow spotting quality drops and performing quick comparisons between different processed files.
The summary view provides overall video quality statistics:
the average metric value - an indication of the overall quality of the video
minimum and maximum metric values for the video,
the standard deviation of the values - an indication of quality variability over time (usually a close to constant quality is desired).
The summary view can be easily used to sort out videos according to their overall quality.
After using the summary view to get a glimpse at the overall quality you can switch to detailed view to see metric values for each frame, see the evolution of quality over time and by viewing two or more processed files side by side compare their quality frame by frame.
If you want to compare your processed video file to a benchmark video you can use the compare view, select the processed video file as benchmark and check the differences between quality indicators.
Vision is our most evolved sense and visual representations is a very effective way of transmitting information. A graphical representation of the video quality available in quality chart view allows you to easily detect high variations in quality which can results in flickering artifacts. This is especially relevant for MPEG2 and H264 encoding where suboptimal rate control can results in over sized I frames causing quality jumps at GOP boundaries. Also low quality intervals can be easily targeted for visual inspection. Differences in quality between processed video files can be easily observed.
A very accurate way of comparing the quality of the output of encoders is to use the bitrate distortion chart view which gives a graphical representation of the influence bitrate variation has on quality. The quality performance over the entire bitrate range can be observed; this eases the task of choosing the most bandwidth effective encoding profile for a certain quality level.
In order to be shared and organized easily, any number of test results can be stored in a single file; the test results can be loaded at any time to be reviewed or compared to other results stored. You can see for example the evolution of you product by loading all the tests performed in the results viewer and compare them using the views available. A test name and a test description can be stored together with the test so you can write additional data about the conditions in which the tests were performed. The Results Viewer that opens VQR files (files containing stored video quality tests results) is freely available for download on our site so you can share you tests results with people who don’t have VQLab, for example to promote the quality of your encoder to potential clients.
Finally if the views provided are not enough for your needs or storing results as VQR files is not an option VQLab allows exporting the results in CSV format which can be then imported into any spreadsheet application. The charts can also be saved in a range of popular formats.
