README
¶
go-timecode
A Go library for parsing and manipulating SMPTE timecodes and frame rates.
Development of this library is very test-driven to ensure accuracy of the frame and timecode calculations. If you'd like to contribute to this library, adding additional useful test cases is a great place to start!
Installation
go get github.com/spiretechnology/go-timecode
Usage Examples
Parse a timecode (drop frame)
tc, err := timecode.Parse("00:01:02;23", timecode.Rate_23_976)
tc.String() // => 00:01:02;23
tc.Frame() // => 1509
Parse a timecode (non-drop frame)
tc, err := timecode.Parse("00:01:02:23", timecode.Rate_24)
tc.String() // => 00:01:02:23
tc.Frame() // => 1511
Create a timecode from a frame count
tc := timecode.FromFrame(1511, timecode.Rate_24)
tc.String() // => 00:01:02:23
tc.Frame() // => 1511
Algebra with timecodes and frames
tc, err := timecode.Parse("00:01:02:23", timecode.Rate_24)
tc = tc.Add(timecode.Frame(3))
tc.String() // => 00:01:03:02
tc.Frame() // => 1514
Note: parsing timecodes that don't exist in drop frame
Drop frame timecodes skip the first 2 frames of each minute, unless the minute is a multiple of 10. This changes to the first 4 frames of each minute if the frame rate is 59.94.
For instance, in 23.976, the timecode 00:00:59:23 is immediately followed by 00:01:00:02. Two timecodes were dropped: 00:01:00:00 and 00:01:00:01
Those dropped timecodes don't correspond to any actual frame number, and so we need to choose how to resolve those frames. The choice we have made with this library is to round up the next valid frame. If you try to parse 00:01:00:00, the result will be rounded up to 00:01:00:02, which is the next valid frame in the sequence.
Contributing
We welcome contributions that make this library more reliable. To add test cases, fix bugs, or anything else, please submit a pull request.
Documentation
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Index ¶
Constants ¶
This section is empty.
Variables ¶
var ( // 23.976 has exactly 24 frames per second. However, the textual representation of timecodes using this rate // skip two frames every minute, except when the minute is a multiple of 10. This is because 23.976 footage // actually does display at a rate of 23.976 frames each second on televisions. To ensure that the first // timecode in an hour of footage is 00:00:00;00 and the last timecode in that hour is 01:00:00;00, drop // frame was invented. It is purely a matter of presentation. Rate_23_976 = Rate{"23.976", 24, 2, 24000, 1001} Rate_24 = Rate{"24", 24, 0, 24, 1} Rate_30 = Rate{"30", 30, 0, 30, 1} Rate_29_97 = Rate{"29.97", 30, 2, 30000, 1001} Rate_60 = Rate{"60", 60, 0, 60, 1} Rate_59_94 = Rate{"59.94", 60, 4, 60000, 1001} )
var TimecodeRegex = regexp.MustCompile(`^(\d\d)(:|;)(\d\d)(:|;)(\d\d)(:|;)(\d+)$`)
TimecodeRegex is the pattern for a valid SMPTE timecode
Functions ¶
This section is empty.
Types ¶
type Components ¶
type Components struct {
Hours, Minutes, Seconds, Frames int64
}
func (Components) Equals ¶
func (c Components) Equals(other Components) bool
type Frame ¶
type Frame int64
Frame type represents a specific frame index within some media content
type Framer ¶
type Framer interface {
Frame() int64
}
Framer defines the interface for something that can be converted into a specific frame index. Currently, this is limited only to Frame and Timecode
type Timecode ¶
type Timecode struct {
// contains filtered or unexported fields
}
Timecode represents a timecode value, either as a duration or a specific point in time
func FromComponents ¶
func FromComponents(components Components, rate Rate, dropFrame bool) *Timecode
func MustParse ¶
MustParse parses a timecode from a string, and treats it using the provided frame rate value
func Parse ¶
Parse parses a timecode from a string, and treats it using the provided frame rate value
func (*Timecode) Components ¶
func (t *Timecode) Components() Components
Components gets the components of the timecode: hours, minutes, seconds, frames.
Source Files