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Uncompressed video isdigital video that either has never beencompressed or was generated by decompressing previously compressed digital video. It is commonly used by video cameras, video monitors, video recording devices (including general-purpose computers), and in video processors that perform functions such as image resizing, image rotation,deinterlacing, and text and graphics overlay. It is conveyed over various types of baseband digital video interfaces, such asHDMI,DVI,DisplayPort andSDI. Standards also exist for the carriage of uncompressed video overcomputer networks.
SomeHD video cameras output uncompressed video, whereas others compress the video using a lossy compression method such asMPEG orH.264. In any lossy compression process, some of the video information is removed, which createscompression artifacts and reduces the quality of the resulting decompressed video. When editing video, it is preferred to work with video that has never been compressed (or was losslessly compressed) as this maintains the best possible quality, with compression performed after completion of editing.[1]
Uncompressed video should not be confused withraw video. Raw video represents largely unprocessed data (e.g., withoutdemosaicing) captured by an imaging device.
A standalone video recorder is a device that receives uncompressed video and stores it in either uncompressed or compressed form. These devices typically have a video output that can be used to monitor or playback recorded video. When playing back compressed video, the compressed video is uncompressed by the device before being output. Such devices may also have a communication interface, such as Ethernet or USB, which can be used to exchange video files with an external computer, and in some cases, control the recorder from an external computer as well.
Recording to a computer is a relatively inexpensive alternative to implementing a digital video recorder, but the computer and its video storage device (e.g.,solid-state drive,RAID) must be fast enough to keep up with the high video data rate, which in some cases may beHD video or multiple video sources, or both. Due to the extreme computational and storage system performance demands of real-time video processing, other unnecessaryprogram activity (e.g.,background processes,virus scanners) and asynchronous hardware interfaces (e.g.,computer networks) may be disabled, and theprocess priority of the recordingrealtime process may be increased, to avoid disruption of the recording process.
HDMI, DVI and HD-SDI inputs are available asPCI Express (partly multi-channel) orExpressCard,USB 3.0[2] andThunderbolt interface[3][4][5] also for2160p (4K resolution).[6][7]
Software for recording uncompressed video is often supplied with suitable hardware or available for free, e.g.,Ingex.[8]
SMPTE 2022 and2110 are standards for professional digital video overIP networks. SMPTE 2022 includes provisions for both compressed and uncompressed video formats. SMPTE 2110 carries uncompressed video, audio, andancillary data as separatestreams.
Wireless interfaces such asWireless LAN (WLAN,Wi-Fi),WiDi, andWireless Home Digital Interface can be used to transmit uncompressed standard definition (SD) video but not HD video, because the HD bit rates would exceed the network bandwidth. HD can be transmitted using higher-speed interfaces such asWirelessHD andWiGig. In all cases, when video is conveyed over a network, communication disruptions or diminished bandwidth can corrupt the video or prevent its transmission.
Uncompressed video has aconstant bitrate that is based on pixel representation, image resolution, and frame rate:
For example:
The actual data rate may be higher because some transmission media for uncompressed video require definedblanking intervals, which effectively add unused pixels around the visible image.