Audio Session Setup and Operation


Table of Contents

Related topics on this page

Audio Capture Operation

Eyes-N-Ears is designed to allow you to intelligently monitor audio events in almost any type of environment. You can easily monitor household locations, office space, outside entry ways, outdoor settings or any number of various types of locations. Audio capture sessions can be perfomed using standard PC sound cards combined with standard, inexpensive microphones.The two biggest factors that will affect the quality of the recording are background noise levels and the quality of your microphone and sound card.

Above, I referred to the ability to intelligently monitor any type of area. What this means is that when a audio capture session is started, Eyes-N-Ears will constantly sample the sound being generated in an area. When significant amplitude variations are detected, the software will automatically begin recording to disk for a preset period of time. All audio events are stored in sequentially numbered event files so they can be played back at a later time. The duration of each capture event is set via controls provide in the user interface and is discussed in detail below. Also, each capture event file is given a rating of 1-100 to identify the significance of the event. Higher numbers normally indicate higher amplitude levels spread over the duration of the event . This information will be displayed during an event playback session to assist in selecting which files probably contain the greatest collection of amplitude variations.

Intelligently capturing audio significantly reduces disk-storage requirements, but at the same time allows you to capture significant events in the audio spectrum, without losing much detail.

Before starting an audio session, you will want to configure the Eye-N-Ears software. Please read the following to section to help guide you through the two areas of setup.

Table of Contents

Audio Capture Settings

Audio Directory This entry sets the location where you want the audio event files to be stored. If the directory you select does not exist, it will be created when the first audio event occurs.
Email Event To You can configure the software to automatically email all audio event files to you as they occur. To email all audio events, check this radio button. Then enter the email address of the receipient of the audio events (i.e. me@mymail.com)
FTP Event To You can also configure this software to automatically copy all audio event files to a remote FTP server. To FTP all audio events, check this radio button. Then enter the FTP address where the audio events should be copied (i.e. ftp.myftpserver.com). Note that you can only configure either email or FTP copies, not both.
Don't Email or FTP Event Check this radio button is you do not want the audio events to be emailed or copied via FTP to a remote site. The software will continue to save the files in the local audio directory.
Event Duration Set this to the number of seconds of audio you wish to have captured each time an audio event is detected. It is recommend that you keep captures times short if you are using a dial-up phone line for access to your email or FTP server.
Sensitivity This setting determines the sound amplitude required to trigger an audio event. Higher values result in decreased sensitivity. In noisy enviroments you will want to set higher values to lessen the number of audio captures. Also, keep in mind that upon starting an audio capture session, the software automatically calibrates itself to the current audio environment. This operation is performed to lessen the frequency of false triggering. The sensitivity value you set here provides an additional buffer over the value calculated during calibration.
Maximum Events Enter the maximum number of audio events files that you want to be stored on your hard disk. This setting is provide to prevent audio capture settings in a noisy environment from filling up the hard-disk storage.
Current Event This is a read-only field and depicts the ID of last audio event that was recorded.
Grab Video Frame on Audio Events You can configure the software to take a snapshot whenever and audio event is triggered. This would be useful in a room-type environment where the camera could take a picture of someone that has entered or is moving around in a room. The snapshot would be captured when the audio event was triggered.

 

Table of Contents

Audio Hardware Settings

Mono Recording Check this radio button when recording with a single microphone. This is the recommended setting, as it yields the smallest audio event files, but with acceptable audio quality.
Stereo Recording When using two microphones and a stereo jack, you could actually trigger and record audio from 2 different locations. However, due to audio event files sizes, it is recommend that you use the MONO setting. This is especially important if you are remotely transfering audio events via a dial-up connection.
Audio Sample Rate These settings are standard for most wave recording devices. It is recommend that you use the 8Mhz setting (or the GSM compression setting when it becomes availabe). This will keep your audio event files from become excessively large. This is especially important if you are using a dial-up connection for email or FTP forwarding of these files.
Audio In This slide bar control will allow you to adjust the recording level of the microphone jack. Raising the control toward the top of the screen increases the recording level. It is recommend that you set this level to the maximum (all the way up).
Audio Out This setting will adjust the volume of playback of the audio event files. This setting will also affect the volume of the speakers when monitoring an audio capture seting.
Mute Speaker When Recording Putting a check mark in this box will allow the software to make sure the speakers are muted during an audio capture setting. This will prevent anyone from hearing the audio being captured and will also prevent audio feedback in case where the microphone and speakers are in close proximity to each other. If you desire to monitor an audio capture session, then you would leave this box unchecked. It is recommend that the speakers and microphone(s) be placed far enough apart to prevent audio feedback when using this setting.

 

Table of Contents

Start Audio Capture

You can start an audio capture session by either going through the drop-down menu or by using the shortcut control on the main window. To use the menu, simply select Audio Capture from the menu bar and then select Start Audio Capture.

To use the shortcut control, simply press the Audio button located in the Auto Capture button group.

Once you have started an audio capture session, Eye-N-Ears first attempts to automatically calibrate its peak threshold setting to compensate for any background noise in the current audio spectrum. So, during the first 10-20 seconds of starting an audio session, it is important to keep background noises to a minimum. Calibrating a peak threshold is performed to prevent Eyes-N-Ears from constantly triggering on insignificant audio events or events that are merely just background noises. It should be noted; however, that significant levels of background noise can inhibit Eyes-N-Ears ability to properly capture audio events. If background noise levels are too high, Eyes-N-Ears will either constantly capture audio events, or never capture audio events.

After calibration, Eyes-N-Ears will begin normal recording operation. Each time a significant event occurs (where the amplitude exceeds the calibrated peak level), the event will be written into a disk file for the duration assigned in the Audio Capture Settings dialog box. An event counter is incremented each time a capture file is written to disk, and the audio file is stored in the directory specified during software setup. Once Eyes-N-Ears has reached the Maximum Event count for audio files, the event counter will be reset to 1 and new audio events will overwrite existing files. While this may lead to a loss of some audio events, it will help prevent the disk storage from becoming completely full.

Table of Contents