Logo Detector plugin

Plugin BPP_LogoDetector compares the part of TV picture with the loaded template of TV channel logo and when the logo disappears allows to mute sound or to pause the recording. As a result this plugin allows to save up to 30% of space while recording to disk by cutting away the commercials that translated without channel logo, and make the preview more comfortable.

The logo template must be prepared in any graphical editor in advance from the screenshot made in resolution 768*576 pixels. The template prepared from that resolution will be correctly scaled to any resolution supported by tuner.

To increase the precision of detection the mask applied over the logo template. For that the elements of picture that are not parts of logo or moving parts of logo must be filled with particular color. After selection of logo and corresponding mask color the detector will process only the parts of template not filled with that color. The color of the mask may automatically be detected by the color of the top left pixel of loaded template.

If the detector activated and the plugin settings have the option "Show logo" turned on with the transparency other than zero, then, upon selection of logo file, it's picture will appear in the video window, and after that you need to match the loaded logo with one on the screen with the help of appropriate keys.

If the mask color is not selected properly, then the logo on screen will be seen as a whole rectangle with given transparency.

Option "Show logo" is not only needed to control the position on screen during plugin setup. Once you set the plugin and leaved the logo on screen, you may periodically control and adjust it's position.

Option "Transparency" is only needed for conveniency during setting the template position on screen.

Detector plugin has only four user settings, that allow to make correct decision about the presence of logo on the screen.

Allowance for logo shifting

Channel logos may sometimes change their position on screen, shifting to the left or right by the several pixels from their middle position. This setting allows to make detector less sensitive so that it's work may depend less on the position of logo in the screen. But the more this allowance, the more probability of false detection of logo when it is absent.

Time of reaction to the logo disappearing

This setting provides some delay to the decision about logo disappearing. The sensitivity of detector is very high and very little depends on brightness of logo and brightness/contrast settings for the channel. So in most cases you may set this value to 5-10, that will allow the detector to react to logo disappearing almost immediately.

Time of reaction to the logo appearing

This setting vice versa sets the delay on decision wether the logo is appeared back on screen. Because the probability of false detection of absent logo is higher than probability of not seeng the present logo, then this delay you may set to lower value. The sufficient value for most cases is 2-3.

Level of detection

The level from which the detector will treat the logo to be absent. The corresponding to this setting indicator shows the current level. The speed of changing of that level is set by the first two parameters of this setting.

Level of logo match

This setting is introduced to help the detector to determine the appearing of logo more precisely if it is absent on screen. The corresponding to this setting indicator shows the absolute level of matching the template to the image on the screen. When the level of matching is below the set, the detector introduces the correction to the "Time of reaction to the logo appearing", reducing by that the false detection of absent logo.

For almost transparent logos this setting is almost helpless, because the difference between the template and the image may vary in very wide range. In this case you may set this level to zero. It will not heavily influence to the work of detector. For non-transparent logos this level should be set so that when the logo is present on screen, the indicator will never drop below the red level.

Below, in the dropdown lists «Preview» and «Recording» plugin allows to set the action on appearing or disappearing the logo from screen while previewing or recording correspondingly. In preview mode it is available the decreasing the volume to the set percentage, and in recording mode – pausing the recording on absence or presence of logo. Don't forget that to work in recording mode this plugin must be added also to the list of plugins for image processing in selected recording preset.

Also you may show the message on screen on the absence of logo. The text, color, background color and transparency may be set individually for each channel. If you delete the text and turn on the filling by background, then on the absence of logo the screen may simply be shadowed by background colorwhich may be helpful for decreasing the picture brightness.

You may test the logo disappearing not waiting the commercial by simply turning the "Test" mode. In this mode the part of picture will be copied from the center of the screen to the place of logo and will cover it.

P.S. BPP_LogoDetector plugin should not be treated as panacea in figthing the commercials. That's why the plugin is called just as "logo detector" by it's nature. But at nonce this is the most helpful method to cut away a part of unwanted information from TV video. All other methods, such as detection station breaks, sound patterns and levels are very unreliable or require very high computational power and for that may work only as supplementary methods.

List of changes

• Added the output of user message to the screen on logo disappearing;
• Added the setting of allowance to logo shifting in a picture;
• Added volume control of line selected in application (works only in Behold TV application of version 4.10 or higher);
• Added restoring of volume when exiting application during the commercial;
• Added support of RGB24 stream format.

• In the dialog window of detector settings added the indication of current channel's name;
• Added disabling of the background of displayed message;
• Added option that allows to record only video fragments without logo (for gathering statistics on commercials).

• Added automatic settings saving separate for each user profile.

• Added saving of settings on Windows 7.

• Added support of Behold TV instances.

Link to the plugin: BPP_LogoDetector_v123.zip (39.8 kb)

01.03.11