GrabboCam

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GrabboCam

The Interface
The top half of the basic GrabboCam interface is the menu bar and the current video input feed; the bottom half contains most of the application's controls. The controls are organized in several categories: recording, ftp, detection, and notices. Between the controls and the video image there is a status display for messages.

From the File menu you can access the Video Preferences, where you can set your prefered default video input device. This setting can also be done from the Media Preferences, but for the changes to take effect, you will have to restart GrabboCam (that is if it is running). As with the other video recording / capturing programs under Zeta, GrabboCam will also always open the device at 320x240.

Recording
If you are to start using GrabboCam regularly, with high framerates, the recordings will occupy a significant amount of space. A small security is therefore built in to GrabboCam, and it will not be able to fill up more then 98 % of your hard drive's capacity! When the limit is reached, old recordings are deleted until the drive is 95% full. If you have purcased Zeta for mainly doing video related work, we strongly recommend that you get your self a separate partition for these files, or even an extra internal/external hard drive.

GrabboCam lets you set the application's local directory, which is the local folder that it will save the recordings to. By clicking the browse button you will be able to select a different local folder. We strongly recommend that you keep your video files in on place (folder), as it would make it far easier for you to back up these files.

GrabboCam can be your "SpyCam" as you can set timestamps in your recordings. When this option is selected, each still and movie frame recorded will be timestamped with the current date and time. That will be good enough evidence when somebody is stealing food from your fridge during the night!

The Movies controls how your movies are created. If you are running a Pentium 3 or faster, you will easily be able to get 30fps using the Indeo5 Realtime Video codec. Another fast codec is the Photo JPEG, but your mileage may vary.

Movies are created with a filename based on the date and time of the recording: YYYYMMDDHHmmss.ext, where YYYY=year, MM=month, DD=day, HH=hour, mm=minutes, ss=seconds, and ext=avi or mov (the two file formats you can save the videos to).

The option record movie at motion start will create a new movie whenever GrabboCam detects motion (again think of the SpyCam). To avoid missing the onset of motion, the movie will actually start several frames before the motion was detected and the recording will stop automatically several frames after the motion stops.

From the Format option you can select the file format you want to use for your movie.

GrabboCam lets you use various codecs (compression schemes) for your recordings, and you can select the frame rate which GrabboCam is to run. GrabboCam also lets you take pictures (stills) using the JPEG codec, and also for pictures you have the option make the application start recording at motion start. Filenames are of a form similar to that used for movies: YYYYMMDDHHmmss.jpg. Another option is to record pictures periodically (stills recorded at a regular intervals). When you are setting your system to take periodical recordings, once again disk space becomes an important issue. GrabboCam therefore lets you control the rate at which the pictures are periodically recorded. For you to easily keep track of your recordings, you can use
fixed filename.

FTP
As CodyCam, GrabboCam lets you publish your recordings to a FTP server. If you are to run a webserver like PoorMan, RobinHood, or Apache on the same system as GrabboCam, or don't care about web access to your recordings, you can forget this tab. It's possible that you can be making recordings faster than they can be uploaded (esp. at high framerates). You can adjust the framerate, the still recording period or the detection sensitivity to help in these situations. Uploads are queued by GrabboCam, and only one can be underway at any time. The queue does not survive reboots.

You can publish both movies and pictures. When it comes to movies, they will first be published after the recording has ended.

For you to publish the recordings, you would need to now the hostname of the FTP server (or it's IP address), and you would in most cases need both an account and a password. In some cases you would also only be able to publish the recordings to a specific directory, and in those cases you will also have to add the path in these settings.

Detection
A few words about how GrabboCam detects motions. The application uses an "adaptive background subtraction" algorithm to detect motion, as it assumes that incoming video is of a static scene. When motion occasionally occurs, such as a stationary camera on an indoor scene, the background is "learned" in the first few seconds after starting GrabboCam. Small, gradual changes, such as those due to the passing of the sun, are used to update the background model. Large or sudden changes, when present for several frames, trigger a motion event, and recordings are then made if enabled. This technique works relatively well on outdoor scenes as well, but can be triggered by clouds transiting the sun, or when leaves or branches (or their shadows) are moved by the wind.

You can mask out regions you want the motion detector to ignore, such as trees or passing traffic, by using the edit mask feature. The option brings up a window with a low-resolution image of the scene. By using the left mouse button, you can draw a blob over the areas that you want the detector to ignore. You use the right mouse button to clear the mask. The mask will be saved when you exit GrabboCam, and automatically reloaded the next time you start GrabboCam.

You can even adjust the application's sensitivity, from 1 (least sensitive) to 10 (most sensitive). An option is to enable crosshair, which will draw a line at the center of the largest moving object detected.

Notices
When motion is detected, you can get an alert to an email notice, or set the system to play a selected audio file.

When you are selecting that you want the alerts in form of emails, you will have to add your address and the link to put in the email (an URL that will be included in the email), to make it easy for you or other recipients to launch a browser to the webcam page.

When choosing a sound as your alert, choosing the right sound is important. GrabboCam supports the following file formats: .wav, .au, and .aif . Note that there is no support for MP3. In general most people would like to use a short, attention-grabbing sound, that will cut through any audio you happen to be listening to. The sound will be kept in RAM for low-latency response. Use the "browse" button to pick your own sound file.

MIDI
GrabboCam will create a MIDI endpoint called "MotionTracker" that you can connect to any MIDI synth, internal or external. For example, after starting GrabboCam, you can launch the MidiPlayer application, and select MotionTracker in MidiPlayer's Live input menu. Use the PatchBay application to connect MotionTracker to an external connector.

Note messages are sent, based on the center of the largest moving object (crosshair position): Low notes on the left of the image, high notes on the right. Velocity is based on the y-value of the motion center: large velocities at the bottom of the image, low velocities at the top. In typical camera setups, where the camera is looking out and slightly down at the ground, this corresponds to distant objects causing quieter notes than close objects. It's possible to learn to tell in which direction objects are moving based the musical phrase produced, and even tell if they were passing cars, pedestrians, or birds based on the rate notes change, etc. You also just point the camera at yourself, in front of any static background, and have fun waving your hand around, if you're easily amused.

Usage
GrabboCam is meant to be used with a stationary camera, looking on a scene where motion is relatively rare. If a portion of the scene has motion you want to ignore (such as passing traffic), you can mask out that portion using the mask editor (on the "detection" tab).

Using television as source of video is not usually a good idea, since things are constantly in motion on TV. Beware that anytime you use television as a source of video you can expect GrabboCam to be recording almost continuously, which can rapidly eat up disk space (GrabboCam's disk space recycler will avoid the disk from overflowing, of course).

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