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A video codec is software or a device that provides encoding and decoding for digital video, and which may or may not include the use of video compression and/or decompression. The compression may employ lossy data compression, so that quality-measurement issues become important. Shortly after the compact disc became widely available as a digital-format replacement for analog audio, it became feasible to also store and use video in digital form. A variety of technologies soon emerged to do so. The primary goal for most methods of compressing video is to produce video that most closely approximates the fidelity of the original source, while simultaneously delivering the smallest file-size possible. However, there are also several other factors that can be used as a basis for comparison. == Introduction to comparison == The following characteristics are compared in video codecs comparisons: * Video quality per bitrate (or range of bitrates). Commonly video quality is considered the main characteristic of codec comparisons. Video quality comparisons can be ''subjective'' or ''objective''. * Performance characteristics such as compression/decompression speed, supported profiles/options, supported resolutions, supported rate control strategies, etc. * General software characteristics – for example: * * Manufacturer * * Supported OS (Linux, Mac OS, Windows) * * Version number * * Date of release * * Type of license (commercial, free, open source) * * Supported interfaces (VfW, DirectShow, etc.) * * Price (value for money, volume discounts, etc.) 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Comparison of video codecs」の詳細全文を読む スポンサード リンク
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