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SMPTE timecode is a set of cooperating standards to label individual frames of video or film with a time code defined by the Society of Motion Picture and Television Engineers in the SMPTE 12M specification. SMPTE revised the standard in 2008, turning it into a two-part document: SMPTE 12M-1 and SMPTE 12M-2, including new explanations and clarifications. Timecodes are added to film, video or audio material, and have also been adapted to synchronize music. They provide a time reference for editing, synchronization and identification. Timecode is a form of media metadata. The invention of timecode made modern videotape editing possible, and led eventually to the creation of non-linear editing systems. == Basic concepts == SMPTE timecodes ( or ) contain binary coded decimal ''hour:minute:second:frame'' identification and 32 bits for use by users. There are also drop-frame and color framing flags and three extra 'binary group flag' bits used for defining the use of the user bits. The formats of other varieties of SMPTE time codes are derived from that of the longitudinal timecode. Time codes may use a number of frame rates. Common ones are: * 24 frame/sec (film, ATSC, 2k, 4k, 6k) * 25 frame/sec (PAL (Europe, Uruguay, Argentina, Australia), SECAM, DVB, ATSC) * 29.97 (30 ÷ 1.001) frame/sec (NTSC American System (US, Canada, Mexico, Colombia, etc.), ATSC, PAL-M (Brazil)) * 30 frame/sec (ATSC) In general, SMPTE timecode frame rate information is implicit, known from the rate of arrival of the timecode from the medium, or other metadata encoded in the medium. The interpretation of several bits, including the "colour framing" and "drop frame" bits, depends on the underlying data rate. In particular, the drop frame bit is only valid for a nominal frame rate of 30 frame/s: see below for details. More complex timecodes such as vertical interval timecode can also include extra information in a variety of encodings. 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「SMPTE timecode」の詳細全文を読む スポンサード リンク
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