com.peterphi.std.types

Class Timebase

java.lang.Object

com.peterphi.std.types.Timebase

public class Timebase
extends java.lang.Object

Describes a timebase, expressed as a rational number. This is primarily designed for timebases where the numerator is 1 (i.e. where the denominator is the number of samples per second)

Field Summary

Fields

Modifier and Type	Field and Description
static Timebase	HZ_1 1 Hz (1 frame = 1 second)
static Timebase	HZ_1000 1 kHz (1 frame = 1 millisecond.
static Timebase	HZ_1000000 1 MHz (Vidispine transcoder default sampling rate)
static Timebase	HZ_192000
static Timebase	HZ_25
static Timebase	HZ_27000000 27 MHz (sampling rate used by Carbon)
static Timebase	HZ_30
static Timebase	HZ_44100
static Timebase	HZ_48000
static Timebase	HZ_50
static Timebase	HZ_96000
static Timebase	NTSC 29.97 Hz (NTSC)

Constructor Summary

Constructors

Constructor and Description
Timebase(int numerator, int denominator)

Method Summary

Methods

Modifier and Type	Method and Description
boolean	equals(java.lang.Object obj)
int	getDenominator()
static Timebase	getInstance(java.lang.String rate) Parses an encoded timebase.
int	getIntSamplesPerSecond() Samples per second, cast to an integer (accurate only if the numerator is 1)
int	getNumerator()
double	getSamplesPerSecond() The number of samples each second
double	getSecondsPerSample() The number of seconds each sample represents
int	hashCode()
double	resample(double samples, Timebase oldRate) Convert a sample count from one timebase to another
long	resample(long samples, Timebase oldRate) Convert a sample count from one timebase to another Note that this may result in data loss due to rounding.
long	resample(long samples, Timebase oldRate, boolean failOnPrecisionLoss) Convert a sample count from one timebase to another Note that this may result in data loss due to rounding.
long	resamplePrecise(long samples, Timebase oldRate) Convert a sample count from one timebase to another, throwing an exception if precision is lost
java.lang.String	toEncodedString() Return the encoded string representation of this Timebase N.B.
java.lang.String	toString()

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

HZ_25

public static final Timebase HZ_25

HZ_30

public static final Timebase HZ_30

HZ_50

public static final Timebase HZ_50

HZ_44100

public static final Timebase HZ_44100

HZ_48000

public static final Timebase HZ_48000

HZ_96000

public static final Timebase HZ_96000

HZ_192000

public static final Timebase HZ_192000

HZ_1000000

public static final Timebase HZ_1000000

1 MHz (Vidispine transcoder default sampling rate)

HZ_27000000

public static final Timebase HZ_27000000

27 MHz (sampling rate used by Carbon)

HZ_1000

public static final Timebase HZ_1000

1 kHz (1 frame = 1 millisecond. One of the ways MediaInfo uses to express durations/offsets)

HZ_1

public static final Timebase HZ_1

1 Hz (1 frame = 1 second)

NTSC

public static final Timebase NTSC

29.97 Hz (NTSC)

Constructor Detail

Timebase

public Timebase(int numerator,
        int denominator)

Parameters:

numerator - the numerator (the top part of the fraction) - generally 1

denominator - the denominator (the bottom part of the fraction) - e.g. 25 for PAL (with a numerator of 1)

Method Detail

getNumerator

public int getNumerator()

getDenominator

public int getDenominator()

getSamplesPerSecond

public double getSamplesPerSecond()

The number of samples each second

Returns:

getIntSamplesPerSecond

public int getIntSamplesPerSecond()

Samples per second, cast to an integer (accurate only if the numerator is 1)

Returns:

getSecondsPerSample

public double getSecondsPerSample()

The number of seconds each sample represents

Returns:

resample

public long resample(long samples,
            Timebase oldRate)

Convert a sample count from one timebase to another
Note that this may result in data loss due to rounding.

Parameters:

samples -

oldRate -

Returns:

resamplePrecise

public long resamplePrecise(long samples,
                   Timebase oldRate)
                     throws ResamplingException

Convert a sample count from one timebase to another, throwing an exception if precision is lost

Parameters:

samples -

oldRate -

Returns:

Throws:

ResamplingException - if precision is lost during the conversion

resample

public long resample(long samples,
            Timebase oldRate,
            boolean failOnPrecisionLoss)
              throws ResamplingException

Convert a sample count from one timebase to another
Note that this may result in data loss due to rounding.

Parameters:

samples -

oldRate -

failOnPrecisionLoss - if true, precision losing operations will fail by throwing a PrecisionLostException

Returns:

Throws:

ResamplingException

resample

public double resample(double samples,
              Timebase oldRate)

Convert a sample count from one timebase to another

Parameters:

samples -

oldRate -

Returns:

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object

equals

public boolean equals(java.lang.Object obj)

Overrides:

equals in class java.lang.Object

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

toEncodedString

public java.lang.String toEncodedString()

Return the encoded string representation of this Timebase
N.B. does not return string constants such as NTSC or NTSC30

Returns:

getInstance

public static Timebase getInstance(java.lang.String rate)

Parses an encoded timebase.

The following textual representations are valid for time bases:

Its inverse as a rational number. The syntax is {denominator}[:{numerator}], where numerator can be omitted if its value is 1.
• A TimeBaseConstant string
• TimeBaseConstant

The following TimeBaseConstants are currently defined:

TimeBaseConstant	Time base
PAL	25:1
NTSC	30000:1001
NTSC30	30:1

Parameters:

rate -

Returns: