DW Spectrum User Manual

All audio is processed and recorded on the DW Spectrum Server and can be played back using one of the DW Spectrum Clients. DW Spectrum Desktop has the ability to playback audio from all devices open in a layout. To enable this feature, enable Play audio from all cameras on layout in Local Settings. See "Adjusting Volume" for information about managing playback volume.

Audio allows users 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 (see "Using 2-Way Audio" for more information). Many third-party developers also offer analytics solutions involving sound detection to create events in DW Spectrum.

DW Spectrum supports audio from the camera's internal microphone or an external microphone through the camera's audio input. Alternatively, you can connect a microphone to an I/O device (e.g. Axis P8221 Audio Module) or use an all-in-one system with built-in microphones (e.g. Axis Network Speakers).

To provide what is considered lip-synced audio, Digital Watchdog 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.

The Following Audio Codecs Are Supported

•AAC – Advanced Audio Coding is an audio coding standard for lossy digital audio compression.

•G.711 (u-Law/A-law) – an ITU-T PCM speech coding standard providing toll-quality voice compression.

•G.726 – an ITU-T ADPCM speech coding standard with half the bitrate of G.711.

•MPEG Audio (MP1, MP2, and MP3) – an audio coding standard for lossy digital audio compression.