org.restcomm.media.sdp.attributes

Class RtpMapAttribute

java.lang.Object

org.restcomm.media.sdp.fields.AttributeField

org.restcomm.media.sdp.attributes.RtpMapAttribute

All Implemented Interfaces:

SdpField

public class RtpMapAttribute
extends AttributeField

a=rtpmap:[payload type][encoding name]/[clock rate]/[encoding parameters*]

m=audio 49230 RTP/AVP 96 97 98
a=rtpmap:96 L8/8000
a=rtpmap:97 L16/8000
a=rtpmap:98 L16/11025/2

This attribute maps from an RTP payload type number (as used in an "m=" line) to an encoding name denoting the payload format to be used.
It also provides information on the clock rate and encoding parameters. It is a media-level attribute that is not dependent on charset.

Although an RTP profile may make static assignments of payload type numbers to payload formats, it is more common for that assignment to be done dynamically using "a=rtpmap:" attributes.
As an example of a static payload type, consider u-law PCM coded single-channel audio sampled at 8 kHz. This is completely defined in the RTP Audio/Video profile as payload type 0, so there is no need for an "a=rtpmap:" attribute, and the media for such a stream sent to UDP port 49232 can be specified as:

m=audio 49232 RTP/AVP 0

An example of a dynamic payload type is 16-bit linear encoded stereo audio sampled at 16 kHz.
If we wish to use the dynamic RTP/AVP payload type 98 for this stream, additional information is required to decode it:

m=audio 49232 RTP/AVP 98
a=rtpmap:98 L16/16000/2

Author:

Henrique Rosa (henrique.rosa@telestax.com)

Field Summary

Fields

Modifier and Type	Field and Description
static String	ATTRIBUTE_TYPE
static short	DEFAULT_CODEC_PARAMS

Fields inherited from class org.restcomm.media.sdp.fields.AttributeField

ATTRIBUTE_SEPARATOR, BEGIN, BEGIN_LENGTH, builder, FIELD_TYPE, key, value

Fields inherited from interface org.restcomm.media.sdp.SdpField

FIELD_SEPARATOR

Constructor Summary

Constructors

Constructor and Description
RtpMapAttribute()
RtpMapAttribute(int payloadType, String codec, int clockRate, int codecParams)

Method Summary

Methods

Modifier and Type	Method and Description
int	getClockRate()
String	getCodec()
int	getCodecParams()
FormatParameterAttribute	getParameters()
int	getPayloadType()
void	setClockRate(int clockRate)
void	setCodec(String codec)
void	setCodecParams(int codecParams)
void	setParameters(FormatParameterAttribute parameters)
void	setPayloadType(int payloadType)
String	toString()

Methods inherited from class org.restcomm.media.sdp.fields.AttributeField

getFieldType, getKey, getValue

Methods inherited from class java.lang.Object

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

Field Detail

ATTRIBUTE_TYPE

public static final String ATTRIBUTE_TYPE

See Also:

Constant Field Values

DEFAULT_CODEC_PARAMS

public static final short DEFAULT_CODEC_PARAMS

See Also:

Constant Field Values

Constructor Detail

RtpMapAttribute

public RtpMapAttribute()

RtpMapAttribute

public RtpMapAttribute(int payloadType,
               String codec,
               int clockRate,
               int codecParams)

Method Detail

getPayloadType

public int getPayloadType()

setPayloadType

public void setPayloadType(int payloadType)

getCodec

public String getCodec()

setCodec

public void setCodec(String codec)

getClockRate

public int getClockRate()

setClockRate

public void setClockRate(int clockRate)

getCodecParams

public int getCodecParams()

setCodecParams

public void setCodecParams(int codecParams)

getParameters

public FormatParameterAttribute getParameters()

setParameters

public void setParameters(FormatParameterAttribute parameters)

toString

public String toString()

Overrides:

toString in class AttributeField