Definitions

The term „video quality“ is most of the time a subjective impression in our everyday life. However the quality of videos can be measured by different aspects. We decided to define the video quality for capture with cameras (Webcam) with following attributes:

• bitrate: how much information is processed in one second
• video resolution: how many pixels an image has(e.g. 4K, FHD, HD, VGA, …)
• framerate: how many frames there are in a second (e.g. 24, 30, 60, 120, …)
• focal length: how wide is the field of view (e.g. 35mm, 50mm, 85mm, …)
• sensor size: how large is the sensor (e.g. MFT, APSC, FF, …)
• aperture: how much light lets the lens in (e.g. 1.4, 2.8, 5.6, …)
• iso: how sensitive is the sensor to light (e.g. 100, 400, 800, …)
• compression: how much is the pixel data compressed (e.g. 4:2:0, 4:2:2, …)
• dynamic range: how many points are between the brightest and darkest pixel (e.g 7Stops, 13Stops, 21Stops, …)

The slides will be subject to the following aspects:

• bitrate: how much information is processed in one second
• video resolution: how many pixels an image has(e.g. 4K, FHD, HD, VGA, …)
• compression: how much is the pixel data compressed (e.g. 4:2:0, 4:2:2, …)

The audio is defined with these aspects:

• audio resolution: how many data points are in one second (e.g. 41kHz, 44kHz, 192kHz, …)
• Noise Floor: how noisy is the signal (e.g. -20dB, …)
• Gain: how is the Signal to Noise ratio

We define two categories for video and audio quality: good and bad

Bad quality webcam videos are defined by:

• low bitrate
• low video resolution
• low framerate
• small sensor size
• high compression
• fixed aperture
• fixed focal length
• auto iso
• limited dynamic range

The bad video will be recorded by a low quality (integrated) webcam.

Bad quality slide videos are defined by:

• low bitrate
• low video resolution
• high compression

The bad slide video will be rendered (and re-recorded).

Bad quality audio is defined by:

• low audio resolution
• high Noise Floor

The bad audio will be recorded by an integrated microphone.

The bad data will also have frames skipped, video & audio lags and compression artefacts.

Good quality webcam videos are defined by:

• high bitrate
• high video resolution
• high framerate
• large sensor size
• low compression

The good video will be recorded by a high quality (external) DSLM.

Good quality slide videos are defined by:

• high bitrate
• high video resolution
• low compression

The good slide video will be rendered.

Good quality audio is defined by:

• high audio resolution
• low Noise Floor

The good audio will be recorded by a condenser / large membrane external microphone.

In the study we have four groups

• Good video, good audio
• Good video, bad audio
• Bad video, good audio
• Bad video, bad audio

to determine if there is an effect as a basis for potential further studies later with single aspects changed between groups. The good /bad webcam and slide videos will linked together as they would be in real life applications as well, as even a good camera would struggle with bandwith limitations, simulated by our bad video definition.