Benefits of Audio in a VMS
An increasing number of organizations across various industries are beginning to use audio in their Nx Witness 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
Nx Witness 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.
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, but sometimes better equipment is required to achieve the goals of the system and you will have to use, expensive, directional microphones with or without a decent windjammer. The output is always dependent on the input.
Law and Regulations
Although audio is becoming a more common use case, it is important 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.
If you have any questions related to this topic or you want to share your experience with other community members or our team, please visit and engage in our support community or reach out to your local reseller.
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