javax.media
类 Buffer

java.lang.Object
  javax.media.Buffer

直接已知子类：

ExtBuffer

public class Buffer
extends java.lang.Object

A Buffer is a media-data container that carries media data from one processing stage to the next inside of a Player or Processor. Buffer objects are also used to carry data between a buffer stream and its handler.

A Buffer object maintains information such as the time stamp, length, and Format of the data it carries, as well as any header information that might be required to process the media data.

从以下版本开始：

JMF 2.0

另请参见：

PlugIn, PushBufferStream, PullBufferStream

字段摘要

protected java.lang.Object	data The object that actually holds the media data chunk for this Buffer.
protected long	duration The duration of the data held in this Buffer, in nanoseconds.
static int	FLAG_BUF_OVERFLOWN Indicates that some buffer queue in the data flow path from where this buffer comes from is overflown.
static int	FLAG_BUF_UNDERFLOWN Indicates that some buffer queue in the data flow path from where this buffer comes from is underflown.
static int	FLAG_DISCARD Indicates that the media data in this Buffer should be ignored.
static int	FLAG_EOM Indicates that this Buffer marks the end of media for the data stream.
static int	FLAG_FLUSH This is a marker bit used by the system.
static int	FLAG_KEY_FRAME Indicates that this Buffer starts with a key frame.
static int	FLAG_LIVE_DATA Indicates that the data is arriving from a live (real-time) source.
static int	FLAG_NO_DROP Indicates that this Buffer will not be dropped even if the frame is behind the presentation schedule.
static int	FLAG_NO_SYNC Indicates that this Buffer is not to be presented in sync with the scheduled presentation time.
static int	FLAG_NO_WAIT Indicates that this Buffer will not be waited on even if the frame is ahead of the presentation schedule.
static int	FLAG_RELATIVE_TIME Indicates that the Buffer carries a time stamp that's in relative time units.
static int	FLAG_RTP_MARKER This is a marker bit for RTP.
static int	FLAG_RTP_TIME Indicates that the Buffer carries a time stamp that's in RTP (NTP) time units.
static int	FLAG_SID Indicates that this Buffer contains only SID (silence information description) frames.
static int	FLAG_SILENCE Indicates that this Buffer contains only silence frames.
static int	FLAG_SYSTEM_MARKER This is a marker bit used by the system.
static int	FLAG_SYSTEM_TIME Indicates that the Buffer carries a time stamp that's relative to the SystemTimeBase.
protected int	flags A flag mask that describes the boolean attributes enabled for this Buffer.
protected Format	format The Format of the chunk of data in this Buffer.
protected java.lang.Object	header Header information (such as RTP header) for this data chunk.
protected int	length For array data type, states how many samples are valid in the array.
protected int	offset For array data type, points to the starting point (offset) into the array where the valid data begins.
static long	SEQUENCE_UNKNOWN The getSequenceNumber method returns this value if the sequence number is not known.
protected long	sequenceNumber The sequence number of this Buffer.
static long	TIME_UNKNOWN The getTimeStamp method return this value if the time stamp of the media is not known.
protected long	timeStamp The time stamp of the data held in this Buffer, in nanoseconds.

构造方法摘要

Buffer()

方法摘要

java.lang.Object	clone() Clone a buffer.
void	copy(Buffer buffer) Copy the attributes from the specified Buffer into this Buffer
void	copy(Buffer buffer, boolean swapData) Copy the attributes from the specified Buffer into this Buffer.
java.lang.Object	getData() Gets the internal data object that holds the media chunk contained in this Buffer.
long	getDuration() Gets the duration of this Buffer.
int	getFlags() Gets the mask of the flags set for this Buffer.
Format	getFormat() Get the Format of the data in this Buffer.
java.lang.Object	getHeader() Gets the header information for the media chunk contained in this Buffer.
int	getLength() Gets the length of the valid data in this Buffer if the data is held in an array.
int	getOffset() If the media chunk for this Buffer is held in an array, gets the offset into the data array where the valid data begins.
long	getSequenceNumber() Gets the sequence number of this Buffer.
long	getTimeStamp() Gets the time stamp of this Buffer.
boolean	isDiscard() Checks whether or not this Buffer is to be discarded.
boolean	isEOM() Checks whether or not this Buffer marks the end of the media stream.
void	setData(java.lang.Object data) Sets the internal data object that holds the media chunk.
void	setDiscard(boolean discard) Sets the DISCARD flag for this Buffer.
void	setDuration(long duration) Sets the duration of this Buffer.
void	setEOM(boolean eom) Sets the EOM flag for this Buffer.
void	setFlags(int flags) Sets the flag mask for this Buffer.
void	setFormat(Format format) Sets the Format of the data in this Buffer.
void	setHeader(java.lang.Object header) Sets the header information for the media chunk.
void	setLength(int length) Sets the length of the valid data stored in this Buffer if the data is held in an array.
void	setOffset(int offset) If the media chunk for this Buffer is held in an array, sets the offset into the array where the valid data begins.
void	setSequenceNumber(long number) Sets the sequence number of this Buffer.
void	setTimeStamp(long timeStamp) Sets the time stamp of this Buffer.

从类 java.lang.Object 继承的方法

equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

字段详细信息

timeStamp

protected long timeStamp

The time stamp of the data held in this Buffer, in nanoseconds. The time stamp marks the time when presentation of this Buffer is to begin. If the start time for this Buffer is not known, this time stamp is set to TIME_UNKNOWN.

duration

protected long duration

The duration of the data held in this Buffer, in nanoseconds. The duration specifies how long it will take for this Buffer to be presented when the playback rate is 1.0. If the duration for this Buffer is not known, it is set to TIME_UNKNOWN.

format

protected Format format

The Format of the chunk of data in this Buffer.

flags

protected int flags

A flag mask that describes the boolean attributes enabled for this Buffer. This mask is set to the logical sum of all of the flags that are set.

另请参见：

FLAG_EOM, FLAG_DISCARD, FLAG_SILENCE, FLAG_SID, FLAG_KEY_FRAME, FLAG_NO_DROP, FLAG_NO_WAIT, FLAG_NO_SYNC, FLAG_RELATIVE_TIME, FLAG_SYSTEM_TIME, FLAG_RTP_TIME, FLAG_FLUSH, FLAG_SYSTEM_MARKER, FLAG_RTP_MARKER

data

protected java.lang.Object data

The object that actually holds the media data chunk for this Buffer. It can be an array type (such as byte[]) or any other type of object. Use instanceOf to determine what type it is.

header

protected java.lang.Object header

Header information (such as RTP header) for this data chunk. It can be of any type. Use instanceOf to determine what type it is.

length

protected int length

For array data type, states how many samples are valid in the array. (The array might be larger than the actual media length).

offset

protected int offset

For array data type, points to the starting point (offset) into the array where the valid data begins.

sequenceNumber

protected long sequenceNumber

The sequence number of this Buffer. The sequence number of adjacent Buffer objects in a sequence should differ by 1: positive 1 if the media is playing forward, negative 1 if the media is played in reverse. If the sequence number is not known, SEQUENCE_UNKNOWN is specified.

FLAG_EOM

public static final int FLAG_EOM

Indicates that this Buffer marks the end of media for the data stream. The Buffer might or might not contain valid data to be processed. The length and data attributes need to be examined to determine whether or not this Buffer contains valid data.

另请参见：

常量字段值

FLAG_DISCARD

public static final int FLAG_DISCARD

Indicates that the media data in this Buffer should be ignored.

另请参见：

常量字段值

FLAG_SILENCE

public static final int FLAG_SILENCE

Indicates that this Buffer contains only silence frames.

另请参见：

常量字段值

FLAG_SID

public static final int FLAG_SID

Indicates that this Buffer contains only SID (silence information description) frames.

另请参见：

常量字段值

FLAG_KEY_FRAME

public static final int FLAG_KEY_FRAME

Indicates that this Buffer starts with a key frame.

另请参见：

常量字段值

FLAG_NO_DROP

public static final int FLAG_NO_DROP

Indicates that this Buffer will not be dropped even if the frame is behind the presentation schedule.

另请参见：

常量字段值

FLAG_NO_WAIT

public static final int FLAG_NO_WAIT

Indicates that this Buffer will not be waited on even if the frame is ahead of the presentation schedule.

另请参见：

常量字段值

FLAG_NO_SYNC

public static final int FLAG_NO_SYNC

Indicates that this Buffer is not to be presented in sync with the scheduled presentation time. In other words, the Buffer will not be dropped or waited on if it's behind or ahead of schedule.

另请参见：

常量字段值

FLAG_SYSTEM_TIME

public static final int FLAG_SYSTEM_TIME

Indicates that the Buffer carries a time stamp that's relative to the SystemTimeBase. This flag is generally set for data transferred from hardware capture DataSources that uses the system clock.

另请参见：

常量字段值

FLAG_RELATIVE_TIME

public static final int FLAG_RELATIVE_TIME

Indicates that the Buffer carries a time stamp that's in relative time units. This means that individual time stamps are not measured against any indentifiable absolute origin--only the difference between the time stamps of two consecutive buffers carries useful information. (This is the time difference between the two packets.)

另请参见：

常量字段值

FLAG_FLUSH

public static final int FLAG_FLUSH

This is a marker bit used by the system. When this flag is set, it marks a zero-length Buffer generated by the system to flush the data path. Do not attempt to use or overwrite this flag.

另请参见：

常量字段值

FLAG_SYSTEM_MARKER

public static final int FLAG_SYSTEM_MARKER

This is a marker bit used by the system. Do not attempt to use or overwrite this flag.

另请参见：

常量字段值

FLAG_RTP_MARKER

public static final int FLAG_RTP_MARKER

This is a marker bit for RTP. Indicates that the Buffer is the last packet of a video frame.

另请参见：

常量字段值

FLAG_RTP_TIME

public static final int FLAG_RTP_TIME

Indicates that the Buffer carries a time stamp that's in RTP (NTP) time units.

另请参见：

常量字段值

FLAG_BUF_OVERFLOWN

public static final int FLAG_BUF_OVERFLOWN

Indicates that some buffer queue in the data flow path from where this buffer comes from is overflown. When such condition occurs, the processing element should attempt to speed up the procesing of this buffer object to reduce the overflow.

另请参见：

常量字段值

FLAG_BUF_UNDERFLOWN

public static final int FLAG_BUF_UNDERFLOWN

Indicates that some buffer queue in the data flow path from where this buffer comes from is underflown. When such condition occurs, the processing element should attempt to speed up the procesing of this buffer object to reduce the underflow.

另请参见：

常量字段值

FLAG_LIVE_DATA

public static final int FLAG_LIVE_DATA

Indicates that the data is arriving from a live (real-time) source.

另请参见：

常量字段值

TIME_UNKNOWN

public static final long TIME_UNKNOWN

The getTimeStamp method return this value if the time stamp of the media is not known.

另请参见：

常量字段值

SEQUENCE_UNKNOWN

public static final long SEQUENCE_UNKNOWN

The getSequenceNumber method returns this value if the sequence number is not known.

另请参见：

常量字段值

构造方法详细信息

Buffer

public Buffer()

方法详细信息

getFormat

public Format getFormat()

Get the Format of the data in this Buffer.

setFormat

public void setFormat(Format format)

Sets the Format of the data in this Buffer.

参数：

format - The Format of the data.

getFlags

public int getFlags()

Gets the mask of the flags set for this Buffer. The integer value of the mask is equal to the logical sum of the flags that are set.

另请参见：

FLAG_EOM, FLAG_DISCARD, FLAG_SILENCE, FLAG_SID, FLAG_KEY_FRAME, FLAG_NO_DROP, FLAG_NO_WAIT, FLAG_NO_SYNC, FLAG_RELATIVE_TIME, FLAG_FLUSH, FLAG_SYSTEM_MARKER, FLAG_RTP_MARKER

setFlags

public void setFlags(int flags)

Sets the flag mask for this Buffer. The integer value of the mask is equal to the logical sum of the flags that are set.

另请参见：

FLAG_EOM, FLAG_DISCARD, FLAG_SILENCE, FLAG_SID, FLAG_KEY_FRAME, FLAG_NO_DROP, FLAG_NO_WAIT, FLAG_NO_SYNC, FLAG_RELATIVE_TIME, FLAG_FLUSH, FLAG_SYSTEM_MARKER, FLAG_RTP_MARKER

isEOM

public boolean isEOM()

Checks whether or not this Buffer marks the end of the media stream. Even it isEOM returns true, the Buffer might still contain valid data--check the length of the Buffer.

This method provides a convenient alternative to using getFlags to check the EOM flag.

返回：

true if the EOM flag is enabled, false if it is not.

另请参见：

getFlags(), FLAG_EOM

setEOM

public void setEOM(boolean eom)

Sets the EOM flag for this Buffer. If the EOM flag is enabled, this is the last Buffer in the media stream.

This method provides a convenient alternative to using setFlags to enable or disable the EOM flag.

参数：

eom - A boolean value that contains the EOM status of the Buffer. Set to true to enable the EOM flag, false to disable the flag.

另请参见：

setFlags(int), FLAG_EOM

isDiscard

public boolean isDiscard()

Checks whether or not this Buffer is to be discarded.

This method provides a convenient alternative to using getFlags to check the DISCARD flag.

返回：

true if the DISCARD flag is enabled, false if it is not.

另请参见：

getFlags(), FLAG_DISCARD

setDiscard

public void setDiscard(boolean discard)

Sets the DISCARD flag for this Buffer. If the DISCARD flag is enabled, this Buffer is to be discarded.

This method provides a convenient alternative to using setFlags to enable or disable the DISCARD flag.

参数：

discard - A boolean value that contains the DISCARD status of the Buffer. Set to true to enable the EOM flag, false to disable the flag.

另请参见：

setFlags(int), FLAG_DISCARD

getData

public java.lang.Object getData()

Gets the internal data object that holds the media chunk contained in this Buffer.

返回：

The data object that holds the media chunk for this Buffer. It can be an array type (such as byte[]) or any other type of object. Use instanceOf to determine what type it is.

另请参见：

data

setData

public void setData(java.lang.Object data)

Sets the internal data object that holds the media chunk.

参数：

data - The data object that holds the media data chunk for this Buffer. It can be an array type (such as byte[]) or any other type of object.

另请参见：

data

getHeader

public java.lang.Object getHeader()

Gets the header information for the media chunk contained in this Buffer.

返回：

The object that holds the header information. Use instanceOf to determine what type the header object is.

另请参见：

header

setHeader

public void setHeader(java.lang.Object header)

Sets the header information for the media chunk.

参数：

header - The header object that holds the media data chunk for this Buffer.

另请参见：

header

getLength

public int getLength()

Gets the length of the valid data in this Buffer if the data is held in an array.

返回：

The length of the valid data in the data array that holds the media chunk for this Buffer.

另请参见：

length

setLength

public void setLength(int length)

Sets the length of the valid data stored in this Buffer if the data is held in an array.

参数：

length - The length of the valid data in the data array that holds the media chunk for this Buffer.

另请参见：

length

getOffset

public int getOffset()

If the media chunk for this Buffer is held in an array, gets the offset into the data array where the valid data begins.

setOffset

public void setOffset(int offset)

If the media chunk for this Buffer is held in an array, sets the offset into the array where the valid data begins.

参数：

offset - The starting point for the valid data.

另请参见：

offset

getTimeStamp

public long getTimeStamp()

Gets the time stamp of this Buffer.

返回：

The Buffer time stamp, in nanoseconds.

另请参见：

timeStamp

setTimeStamp

public void setTimeStamp(long timeStamp)

Sets the time stamp of this Buffer.

参数：

timeStamp - The time stamp for the Buffer, in nanoseconds.

另请参见：

timeStamp

getDuration

public long getDuration()

Gets the duration of this Buffer.

返回：

The Buffer duration, in nanoseconds.

另请参见：

duration

setDuration

public void setDuration(long duration)

Sets the duration of this Buffer.

参数：

duration - The duration for the Buffer, in nanoseconds.

另请参见：

duration

setSequenceNumber

public void setSequenceNumber(long number)

Sets the sequence number of this Buffer. Sequence numbers increase or decrease by 1 for each sequential Buffer, indicating the order in which the data is to be processed. Can be used to identify lost samples of data.

参数：

number - The sequence number for the Buffer.

另请参见：

sequenceNumber

getSequenceNumber

public long getSequenceNumber()

Gets the sequence number of this Buffer.

返回：

The sequence number of this Buffer.

另请参见：

sequenceNumber

copy

public void copy(Buffer buffer)

Copy the attributes from the specified Buffer into this Buffer

参数：

buffer - The input Buffer the copy the attributes from.

copy

public void copy(Buffer buffer,
                 boolean swapData)

Copy the attributes from the specified Buffer into this Buffer. If swapData is true, the data values are swapped between the buffers, otherwise the data value is copied.

参数：

buffer - The input Buffer the copy the attributes from.

swapData - Specifies whether the data objects are to be swapped.

clone

public java.lang.Object clone()

Clone a buffer.

覆盖：

类 java.lang.Object 中的 clone