Editing SMPTE timecode (section)

== Basic concepts ==
[[Image:EmbeddedSynchronousSignalling.png|thumb|350px|SMPTE timecode signal (A logic value 1 is expressed by a transition at the midpoint of a period. A logic value 0 is expressed by the absence of such a transition.) compared to the outwardly-similar [[Manchester code]] (A logic value 0 is expressed by a high-to-low transition, a logic value 1 by low-to-high transition at the midpoint of a period).]]

SMPTE timecode is presented in ''hour:minute:second:frame'' format and is typically represented in 32 bits using [[binary-coded decimal]]. 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 timecode are derived from that of the [[linear timecode]]. More complex timecodes such as [[vertical interval timecode]] can also include extra information in a variety of encodings.

Sub-second timecode time values are expressed in terms of frames. Common supported [[frame rate]]s include:
* 23.98 (24 ÷ 1.001) [[frame/s]] (North American HDTV), sometimes also more precisely specified as 23.976. 
* 24 frame/s ([[film]], [[ATSC]], 2K, [[4K resolution|4K]], 6K)
* 25 frame/s ([[PAL]] (Europe, Uruguay, Argentina, Australia), [[SECAM]], [[DVB]], ATSC)
* 29.97 (30 ÷ 1.001) frame/s ([[NTSC]] American System (U.S., Canada, Mexico, Colombia, et al.), ATSC, [[PAL-M]] (Brazil))
* 30 frame/s ([[ATSC]])

In general, SMPTE timecode frame rate information is implicit, known from the rate of arrival of the timecode from the medium. It may also be specified in other metadata encoded in the medium. The interpretation of several bits, including the ''color framing'' and ''drop frame'' bits, depends on the underlying data rate. In particular, the drop frame bit is only valid for 29.97 and 30&nbsp;frame/s