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Generalized Timing Formula
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<p>Generalized Timing Formula is a standard by <a href="/facts/VESA/tWrcxDNt">VESA</a> which defines exact parameters of the <a href="/facts/Component_video/UEXxJ2gy">component video signal</a> for analogue <a href="/facts/VGA/8GGsGTSc">VGA</a> display interface. </p><p>The video parameters defined by the standard include <a href="/facts/Horizontal_blanking/qB5cMCSj">horizontal blanking</a> (retrace) and <a href="/facts/Vertical_blanking_interval/2lhsCf2S">vertical blanking intervals</a>, <a href="/facts/Horizontal_scan_rate/VdUepaA5">horizontal frequency</a> and <a href="/facts/Refresh_rate/7mGJs7Dz">vertical frequency</a> (collectively, pixel clock rate or video <a href="/facts/Signal_bandwidth/7eMDzfJI">signal bandwidth</a>), and <a href="/facts/Horizontal_sync/VdUepaA5">horizontal</a>/<a href="/facts/Vertical_sync/4NJJew1c">vertical sync</a> polarity. Unlike predefined discrete modes (VESA DMT), any mode in a range can be produced using a formula by GTF. </p><p>A GTF-compliant display is expected to calculate the blanking intervals from the signal frequencies, producing a properly centered image. At the same time, a compliant graphics card is expected to use the calculation to produce a signal that will work on the display — either a GTF default formula for then-ordinary CRT displays or via a custom formula provided via <a href="/facts/Extended_Display_Identification_Data/WRY4Fueg">Extended Display Identification Data</a> (EDID) signaling. </p><p>These parameters are used by the <a href="/facts/XFree86_Modeline/nHDJ4ppc">XFree86 Modeline</a>, for example. </p><p>This video timing standard is available for free. </p>