Audio and video feed generation

One of Loadero's features is the ability to supply fake media feeds during tests. This feature mainly concerns services that require a webcam or microphone to fully cover app logic. In Loadero supplying fake media feeds can be accomplished by simply selecting the desired audio and video feed type when creating a participant. This media feed will be used to simulate a webcam and a microphone that a physical machine could have, whenever the participant is prompted to use their microphone or webcam. Different types of fake media allow simulating users with higher or lower resolution cameras.

info

Loadero automatically handles webcam and microphone permissions in the background. You will not have to deal with permission management in your script.

caution

Media selection is applied to participants using the Google Chrome browser only. For Mozilla Firefox browser the built-in fake media feed will be always used, regardless of the selected feed for the participant.

Audio feed values and their properties

All of the audio feeds provided by Loadero have the following properties:

Sample rate: 44.1 kHz
Number of channels: 2
Audio bitrate (uncompressed): 1 411 kbps

The table below shows all of the available audio feeds along with a sample of what they sound like, and a general description. The given sample will be repeated on a loop when the appropriate audio feed is being used in an application.

info

When using Loadero's API, you can reference the audio feed type by the values provided in the API identifier column.

Not present in the table, but also an option, is the Default audio feed (API identifier - default). This is not an audio feed created by Loadero, but rather the browser's built-in fake audio feed, which is why a sample for it has not been provided.

Audio feed	Description	API identifier
DTMF tone audio feed	Consists of various DTMF frequencies.	`dtmf`
128kbps audio feed	Audio feed of a male voice speaking, followed by a female voice speaking.	`128kbps`
-20dB audio feed	Noise generally resembling the bustle of a crowded restaurant, consisting of several muffled voices talking over one another and the sounds of clinking eating utensils.	`-20db`
-30dB audio feed	Same as -20db audio feed, just slightly quieter.	`-30db`
-50dB audio feed	Same as -20db audio feed, but significantly quieter.	`-50db`
Silent audio feed	Resembles an audio feed where nothing is being picked up by the microphone.	`silence`
ViSQOL speech audio feed	Audio feed of a male voice speaking, followed by a female voice speaking.	`visqol-speech`

Video feed values and their properties

The table below shows all of the available video feeds along with their properties. A sample of what these video feeds would look like is provided even further below. All video feeds have an aspect ratio of 16 : 9.

Video feeds labeled as "meeting video" are intended to look similar to the kind of video feed you would see in your average online video conference call - a person sitting, looking into the camera and generally displaying little movement. The feeds labeled as "dynamic video" has content where each frame is significantly different from the last, stressing encoders and decoders more. Using dynamic video feeds is likely to result in a higher network consumption in your tests.

Most video feeds have markers added. A video feed marker is a QR code rendered on video feed input that changes every frame. This allows determining the frame rate of the video output. The QR marker for dynamic video feeds is located in the top left of the video feed, whereas for meeting video feeds it is located in the bottom center. Exceptions:

1080p @ 30FPS clean meeting video has no QR markings
1080p video feed with top left side marker positions the QR in the top left instead, of the bottom center

info

When using Loadero's API, you can reference the video feed type by the values provided in the API identifier column.

Not mentioned in the table below, the Default video feed (API identifier - default) option supplies the browser's built-in video feed.

Video feed	Dimensions `px`	FPS	Video bitrate `kbps` (uncompressed)	API identifier
240p @ 5FPS dynamic video	426 x 240	5	6 134	`240p-5fps`
240p @ 15FPS dynamic video	426 x 240	15	18 403	`240p-15fps`
240p @ 30FPS dynamic video	426 x 240	30	36 807	`240p-30fps`
240p @ 30FPS meeting video	426 x 240	30	36 807	`240p-meeting`
360p @ 5FPS dynamic video	640 x 360	5	13 824	`360p-5fps`
360p @ 15FPS dynamic video	640 x 360	15	41 472	`360p-15fps`
360p @ 30FPS dynamic video	640 x 360	30	82 945	`360p-30fps`
360p @ 30FPS meeting video	640 x 360	30	82 945	`360p-meeting`
480p @ 5FPS dynamic video	854 x 480	5	24 595	`480p-5fps`
480p @ 15FPS dynamic video	854 x 480	15	73 786	`480p-15fps`
480p @ 30FPS dynamic video	854 x 480	30	147 572	`480p-30fps`
480p @ 30FPS meeting video	854 x 480	30	147 572	`480p-meeting`
720p @ 5FPS dynamic video	1280 x 720	5	55 296	`720p-5fps`
720p @ 15FPS dynamic video	1280 x 720	15	165 888	`720p-15fps`
720p @ 30FPS dynamic video	1280 x 720	30	331 777	`720p-30fps`
720p @ 30FPS meeting video	1280 x 720	30	331 777	`720p-meeting`
1080p @ 5FPS dynamic video	1920 x 1080	5	124 416	`1080p-5fps`
1080p @ 15FPS dynamic video	1920 x 1080	15	373 248	`1080p-15fps`
1080p @ 30FPS dynamic video	1920 x 1080	30	746 497	`1080p-30fps`
1080p @ 30FPS meeting video	1920 x 1080	30	746 497	`1080p-meeting`
1080p @ 30FPS clean meeting video	1920 x 1080	30	746 497	`1080p-meeting-clean`
1080p video feed with top left side marker	1920 x 1080	30	746 497	`1080p-marked-top-left`

tip

Different resolutions and audio qualities have different constraints on network and server load.