Benefits of Audio in a VMS

An increasing number of organizations across various industries are beginning to use audio in their VMS systems. Whether it is through the use of audio in interrogation rooms, riot control, or the observation of elderly and disabled people, more and more applications utilizing audio are on the rise.

Audio allows operators to have a better understanding of what is happening at the scene. In cases where a loudspeaker is present, it enables the option to communicate with people present at the scene.

Many third-party developers also recognize the use of audio in a VMS system. They offer analytics solutions such as sound detection, gunshot detection, and argument detection to create events within a VMS system.

How Nx Witness Handles Audio

Our VMS supports audio in various codecs, either through the camera via an internal microphone or an external microphone through the audio input of the camera. There are also options to connect a microphone to an I/O device, such as the Axis P8221 I/O unit. All-in-one systems such as the Axis Network Speakers with its built-in microphones can also be used.

To provide what most people consider lip-synced audio, we enabled the synchronization of audio and video in our source code, since each camera has the option to provide the same timestamp for both the video and the audio stream.

For the best results, the following prerequisites need to be met: accurate synchronization timing in the RTSP stream of the cameras, appropriate network performance, and sufficient resources in the server-client environment. 

All audio is processed and recorded on the Nx Server service and can be used with the help of either Nx Desktop or Nx Mobile. 

Considerations

When you want to use audio, it is important to consider the goal of the audio. Do you want to hear if people are having a heated discussion, or do you want to be able to understand the conversation word-by-word? 

Also, the environment plays an essential role in the choice of equipment. Sometimes the in-camera microphone, which in general is an omnidirectional microphone without a windjammer, will do just fine. Sometimes better equipment is required to achieve the goals of the system, and you will have to use, more expensive, directional microphones with or without a decent windjammer. The output is always dependent on the input. 

Audio for, specific, observational purposes

In the healthcare industry, audio plays a crucial role in detecting subtle sounds from patients, enabling night care professionals stationed at the central nurse station to stay alert and responsive. However, conventional audio detection systems often fall short when it comes to generating alarms for abnormal breathing patterns, patients getting out of bed, or other irregularities.

To address this limitation, we have incorporated a helpful feature in our system, called 'Play audio from all cameras on layout'.

You can enable this feature By navigating to the Local Settings menu, tab General, section Misc, you can enable the option Play audio from all cameras on layout.

This functionality allows you to listen to all sounds simultaneously broadcasted from the cameras displayed on the layout, providing a comprehensive audio monitoring experience.

Law and Regulations

Although audio is becoming a more common use case, it is essential to familiarize yourself with local laws and regulations regarding audio listening and recording. In general, there are more restrictions to be aware of with audio than there are for video only. So please keep this in mind if you choose to process audio in your surveillance system.