The Regular viewer shows a live stream from the selected videodevice and takes snapshots. These snapshots can be
You can perform one, two, or all three of these actions on the snapshot, but the filename of the snapshot is the same for all actions.
The window for a Regular Viewer looks like this:
From top to bottom, there's a toolbar, the main viewer area and the statusbar.
The toolbar contains all the buttons needed for operating the webcam viewer. The first four buttons are used to control the webcam video device itself. The rest performs various settings and toggles.
The buttons are are, from left to right:
It is possible that one or more buttons are disabled (grayed out). In that case the device doesn't support that particular function (for example, a webcam does not have tuning capabilities).
Clicking on one of the video control buttons will open a dialog with controls.
Under Linux, all dialogs are actually different tabs on a single dialog (except Tuning).
The control are described fully in the section
Video controls below.
TV cards have one or more tuners on board; these can be used to tune into
stations, either from an aerial or cable. It is handy to have a chart
ready with the frequencies of your local television stations or cable company.
The controls in the tuning dialog are described below in detail.
Some devices (usually TV cards) have an actual mute settings;
this should not be confused with muting the soundcard (assuming the
sound from the TV card is routed through a soundcard in the system). This
button mutes the sound when depressed. It acts like a toggle, so clicking
it a second time will unmute the sound.
Clicking this button
will show this dialog:
This dialog is used to set 3 things:
The top half of the dialog has controls for the filename; it consists of 3 parts: the basename, which is simply the first part of the filename. This filename may be augmented with nothing at all (the same filename is user over and over again), a timestamp or a sequence number. The timestamp is of the form yyyymmdd-hhmmss, in a 24 hour format. This allows for easy sorting and selection of pictures for a particular date or time.
The sequence number is handy if you only want to keep the last N pictures; after the final sequence number is used, numbering starts again at 1. The sequence number is padded with leading zeroes to make sorting easier (e.g. '001' is used as the first sequence number if the maximum is between 100 and 1000).
It is possible to print a message at the bottom of the image, together with an optional timestamp. Your message can be entered in edit input box in the bottom-left corner of the dialog. With the two buttons you can select a font and a color.
The final part of the dialog, at the bottom-right cornes specifies what what you want to do with the image. There are 3 options:
Using a script offers the greatest flexibility for processing the image, but there are two things to remember: a) the script must be in the PATH, or you must supply the full pathname to the script; and b) the script may not remove the image; CamStream will automatically remove the file after the script has terminated, if necessary.
This button toggles the snapshot view on or off. When depressed, the
main viewer area is expanded to
the right to make room for the actual snapshot. This way it is possible to see
which image has been saved or uploaded. Each time a snapshot is taken, the
image at the right is updated.
(yes, those are Dutch subtitles)
These two buttons control taking a snapshot immediately, or at regular intervals.
The left button takes a snapshot immediately. The second button is a toggle button;
when clicked, a dialog appears:
You can set the interval in either seconds or minutes; the spinbox has a range of 1-60, so the maximum interval is 1 hour; the minimum 1 second (not recommend, though). The timer starts when you click on
; pressing just closes the dialog.While the timer is active, the button on the toolbar will remain depressed; clicking on the button again will release it, and the timer stops.
This is the area where the actual image is shown. However, when the View snapshot toggle is on, the area is resized to accomodate both the live view and the last snapshot.
In case you are watching TV and you set up your stations properly, you can use the PageUp and PageDown keys to cycle through your stations. See the Tuning dialog for more information.
The status bar has two fields: a message box and the count-down timer.
When uploading images, the message box shows information about the FTP transfer. The timer shows the time until the next snapshot; it is therefor counting down when the timer is on. When the timer is off, it will show "--:--".
This section describes all the panels in the video control dialog(s). For Linux, these are panels in a single dialog.
In here you can select the desired image size, ranging from a stamp-sized 128x96 subQCIF to 640x480 VGA or even more, provided the video device supports this resolution. If a size from the list is not supported by the device, its radiobutton is disabled (grayed out).
The framerate only applies to webcams that have such a setting (like the Philips cams). With other webcams and TV cards this setting has no effect; frames from the device are then fetched as quickly as possible.
The second page of the dialog contains sliders that affect the colour and brightness of the image. Not all devices support all settings, so some sliders may be disabled.
Nearly all devices have brightness and contrast, but the gamma, saturation and hue settings are not always present or behave as expected. Originally, the V4L API defined a whiteness settings for black-and-white cameras only; but this doesn't really make sense so it has been used as gamma for Philips webcams, that really do have a gamma setting.
Colour and hue are for colour saturation resp. hue. The latter is sometimes useful for tuners with a PAL/NTSC decoder if the colors are "wrong". Colour saturation determines how strong the colours should look: moving the slider to the left will produce black-and-white images, and to the right sickly-saturated images.
This page contains the selection for input and tuners; usually TV cards have multiple inputs, and may have more than one tuner (though this is rare). Webcams, on the other hand, have only one "input" and no tuners.
This screenshot shows a typical TV card setup: a Television input (e.g. the tuner), a composite input (also known as CVBS) and S-Video. The latter two are usually available as external inputs where a camera or VCR can be connected to.
This tab contains a lot of controls that affect the image from certain Philips webcams. They are described here shortly:
The Logitech Sphere and Orbit webcams have motor control; the controls on this tab set the angle for pan (horizontal) and tilt (vertical). To move the camera, move the dials to the desired angle and click on
. The camera will move accordingly.Note that the angles are not absolute; in particular, making a lot of small changes back and forth may result in the camera pointing somewhere else than before with the same angle values. This is due to accumulation errors in the positioning mechanism. However, it is possible to reset the camera's position to one that is halfway between its maximum left- and right angle, looking straight ahead. To do so, click on
. The camera will move about for a second and then be at its starting position.The camera's maximum pan and tilt angles have been determined experimentally; it may be possible your camera can move further, but to prevent the positioning mechanism hitting the stops and possibly jam, these safe angles have been chosen by the driver. The Sphere/Orbit camera can pan 70 degrees to the left and right; together with the camera's this allows for a full 180 degree panorama. The vertical tilt ranges from 30 degrees down to 25 degrees up (Other drivers may support different angles).
This rather full dialog contains all you need to program TV stations in CamStream.
At the left is a scrollview that contains all the stations already programmed. At the right are controls to create and remove stations, change the order and set the frequency of the station.
To create a new station, click on Name box.
. If a station was already selected, a copy is made and the name set to "New". The name of the station can be entered in theNow comes the difficult part: setting the right frequency. Most frequency tables for TV station listings put a station in a frequency band and a channel, optionally with a finetuning marker; for example, "UHF 48+". However, the bands and channels are not the same for all countries; there are 3 main systems in use (so called frequency grids): European, American and Japanese. You have to select the proper Frequency grid in order to match the channels in CamStream to your table.
For North America, Europe and Japan the choice is therefor clear; for other continents/countries, you may have to test which grid works best. Next comes the channel; just select the correct one from the System channel list. Apart from the terrestial VHF and UHF frequency bands, there are also channels in the so-called cable band; these are labelled "CATV" in the list.
When you select a channel, the frequency display in the dialog changes accordingly; it shows the current frequency in MHz. In case there is an image but it is not quite optimal, you may need to adjust the frequency with the Finetuning slider until you get a clear picture.
Last, do not forget to select the proper television/color system for the station; again, there has been little consensus worldwide as to the best system (Those of you who think that the digital revolution/analog switchoff will solve all that: forget it...). Again, there are 3 main systems in use: NTSC, PAL and SECAM. NTSC is used mainly in North America and Japan, PAL and SECAM in Europe, with SECAM almost exclusively in France. There are a few variations of all these systems, you may have to test which system works best in your country.
You can browse through your station by clicking on them in the list; you can also use the PageUp and PageDown keys in the main viewer to cycle through the stations.
To remove a station, select it in the list and click on
. To change the order of the stations, select a station and use the and to move the station up and down in the list.To modify a station, select it in the list and use the controls at the right hand side to change the name, frequency or color system. Click on
to save your changes.