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>&kdetv; gebruikt een pluginsysteem zodat het gebruiksvriendelijk en flexibel is. Er zijn verschilende plugintypen, b.v. Video input, On-screen-display, Mixers en afbeeldingfilters. Waneer u &kdetv; voor het eerst start, ga dan naar het configuratiemenu om de benodige plugins te laden voor uw hardware. Erg belangrijk is dat u de juiste videoplugins gebruikt om te verkomen dat u niet tevreden bent over &kdetv;. Lees het gedeelte over de video-plugins voor meer informatie. </para>
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<section id="device_names">
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>Video Device Names</title>
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On most Linux systems, you will notice two kinds of device names in the device list:
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>video4linux - XVideo port <some_number></para>
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These are the devices provided by the XVIDEO plugin. For more information about this
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plugin's capabilities, refer to <link linkend="xvideo_plugin"
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><Your video card's name> Video4Linux (/dev/videoX)</para>
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These are the devices provided by the Video4Linux plugin. For more information about this
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plugin's capabilities, refer to <link linkend="v4l_plugin"
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>Video4Linux Plugin</link
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<section id="xvideo_plugin">
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>XVIDEO Plugin</title>
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>To find out whether you are using a XVIDEO plugin device, look here:
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<link linkend="device_names"
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>Video Device Names</link
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>How does it work?</para>
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The plugin uses the X-Server to display video. It cooperates with an X-Server module that provides
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video playback (the "v4l" module, a video4linux to XVIDEO bridge). The v4l bridge provides very
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CPU efficient video playback because the video image is directly copied from the grabber card into
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the video memory. On most modern hardware, the graphics card will scale the image to the desired
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size. Some hardware even deinterlaces the image (the author of these lines uses a Radeon 9500 card
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with the open-source XFree drivers, this combination provides deinterlacing). Since the v4l bridge
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works in on the XFree server side, it can provide overlay video display without corrupting the
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screen, as opposed to the Video4Linux plugin overlay mode.
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>What features does it provide?</para>
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>Depending on the hardware, a quite good picture quality</para
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>What features does it NOT provide? Why?</para>
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>Image filtering. The images are directly transferred to the graphics card,
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there is no possibility to manipulate them in between.</para
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>Snapshots. Reason: see above.</para
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>Overscan. Reason: see above.</para
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>Audio mode selection. This feature is not exposed by the XVIDEO
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XFree interface.</para
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>Channel scanning without having the VBI decoder running. The feature to determine
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signal strength is not exposed by the XVIDEO XFree interface.</para
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>Image scaling on some very old hardware (e.g. NVIDIA Riva 128).</para
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<section id="v4l_plugin">
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>Video4Linux Plugin</title>
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>To find out whether you are using a Video4Linux plugin device, look here:
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<link linkend="device_names"
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>Video Device Names</link
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>How does it work?</para>
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This plugin has two operation modes:
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It works in Overlay mode when you check the <guimenuitem
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>Use overlay if possible</guimenuitem
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In this mode, the TV image is directly transferred into the graphics card. Since the video window can
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only be updated AFTER it has been moved or resized (&kdetv; is an XFree client) you will notice display
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corruption and heavy flicker whenever you move or resize the window. This is necessary to repaint the
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desktop regions that were corrupted by the video stream. This mode uses almost no CPU resources, but
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should only be used as a fallback if nothing else works.
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>What features does it provide?</para>
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>Audio mode selection.</para
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>Channel scanning without having the VBI decoder running.</para
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>What features does it NOT provide? Why?</para>
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>Image filtering. The images are directly transferred to the graphics card,
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there is no possibility to manipulate them in between.</para
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>Overscan. Reason: see above.</para
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>Image scaling. Most TV hardware (bt8X8 chips) does not support it.</para
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>Grab and Display</para>
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This mode is active when the <guimenuitem
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>Use overlay if possible</guimenuitem
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checked. An image is grabbed from the TV card and stored in a local buffer. This buffer can be
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manipulated in arbitrary ways (deinterlacing, overscan, other filters) and is then being displayed
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using different methods (see below). This is the most flexible way, but also the most
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CPU intensive way &kdetv; offers.
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>Tell me more about the different display modes</para>
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>XVIDEO (with or without shared memory)</para>
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The image is handed over to the graphics card in YUV422 format. Depending on the driver,
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the graphics card or the CPU scale, the image is transformed to RGB with the display's color
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depth and displayed. This is the fastest and most flexible way &kdetv; provides.
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It is strongly recommended that you use this mode since it is the only mode that exposes
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all of &kdetv;'s features. The usage of shared memory MAY yield a small performance benefit.
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The image is handed over to the graphics card in RGB format as a texture for a polygon.
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If you have OpenGL hardware acceleration, the picture is scaled to the desired output
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size by the graphics card, which causes a very low CPU usage. The drawback of this view mode
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is that the OpenGL view mode seems to be unstable. Also, all good deinterlacers use the
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YUV422 image format, which would cause additional conversions that would nullify the hardware
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>X11 (with or without shared memory)</para>
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The image is displayed using standard XFree mechanisms. This is VERY slow and does not
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provide image scaling. Use it as a fallback if nothing else works. Since the video
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image is grabbed in RGB format, all good deinterlacers will not work. The usage of
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shared memory MAY yield a small performance benefit.
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>Framerate selection</para>
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The plugins provide the option of selecting between full and half framerate. Full framerate is only
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useful in conjunction with one of the "good" DScaler deinterlacers since they create
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a new image from the two most recent fields. Full framerate provides "smoother" movement.
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>What features does it provide (assuming XVIDEO display mode is used)?</para>
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>Best picture quality;</para
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>Image filtering in arbitrary ways, for example deinterlacing;</para
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>Audio mode selection;</para
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>Channel scanning without having the VBI decoder running.</para
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>What features does it NOT provide? Why?</para>
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That depends on the display mode. See above. When using XVIDEO mode, all &kdetv; features are
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<section id="mixers">
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>Mixer Plugins</title>
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&kdetv; currently ships two mixer plugins (OSS and ALSA). These should work on all platforms
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&kdetv; supports. Read the <link linkend="faq"
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> when you have trouble adjusting