| FCIF/QCIF | |
| Standards-based formats for communicating between videoconferencing systems from different vendors. QCIF is one quarter of the resolution of FCIF. | |
| FDX (Full Duplex) | |
| Two-way, simultaneous transmission of data; a communication protocol in which the communications channel can send and receive data at the same time. Compare to half-duplex, where information can only be sent in one direction at a time. | |
| Fractional T1 | |
| Service offering data rates between 64 kbps (DS0 rate) and 1.536 Mbps (DS1 rate), in specified intervals of 64 kbps. It is typically provided by a carrier in lieu of a full T-1 connection and is a point-to-point arrangement. A specialized multiplexer is used by the customer to channelize the carrier's signals. | |
| Frame Rate | |
| Frequency in which video frames are displayed on a monitor, typically described in frames-per-second (fps). Higher frame rates improve the appearance of video motion. | |
| Frame store | |
| A system capable of storing complete frames of video information in digital form. This system is used for television standards conversion, computer applications incorporating graphics, video walls and various video production and editing systems. | |
| Full duplex audio | |
| 2-way audio simultaneously transmitted and received without any interference or "clipping." A common feature of room-based videoconferencing systems. | |
| Full-motion video | |
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In the videoconferencing world, the term "full-motion video" is often used and misunderstood. Videoconferencing systems cannot provide 30 fps for all resolutions at all times nor is that rate always needed for a high-quality, satisfying video image. Picture quality must sometimes be sacrificed to achieve interactive visual communication economically. Videoconferencing vendors often use "full-motion video" to refer to any system that isn't still-frame. Most videoconferencing systems today run 10 to 15 fps at 112 Kbps. Full motion video is equivalent to broadcast television video with a frame rate of 30 fps for NTSC signals or 25 fps for PAL signals. Images are sent in real time and motion is continuous. Also known as continuous-motion video. |
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