Module messages

The RTMP Messages

After handshake, both are required to negosiate what are needed for sending/receiving. It consists of following steps:

1. connect
2. releaseStream
3. FCPublish
4. createStream
5. publish

connect

Exchanges informations about their applications each other. In this case, next format is required:

Field	AMF Type	Value
Command Name	String	"connect"
Transaction ID	Number	1
Command Object	Object	See Command Object.

In the command message, we negotiate by using the Action Message Format (v0).

Command Object

The Command Object is written detailed informations of both applications. Concretely, several of following pair is exchanged:

Key	AMF Type	Description
app	String	Server application name.
flashVer	String	Either a flash player version(client) or an FLV encoder version(server).
swfUrl	String	The source SWF file URL.
tcURL	String	The URL to connect server as the TCP. app value is included in this value.
fpad	Boolean	Whether a proxy is used.
audioCodecs	Number	Supported audio codecs.
videoCodecs	Number	Supported video codecs.
videoFunctions	Number	Supported video functions.
pageUrl	String	The URL of web page which SWF file is loaded.
objectEncoding	Number	A version of the Action Message Format.

Note: Something not in above can be exchanged.

Against, the result for connect request is required to be next format:

Field	AMF Type	Value
Command Name	String	"_result" or "_error"
Transaction ID	Number	Same as the connect request
Properties	Object	e.g. server-side informations.
Information	Object	Contents for describing its response.

releaseStream

Tells “Play Path” to the parter. In this case, next format is required:

Field	AMF Type	Value
Command Name	String	"releaseStream"
Transaction ID	Number	A number which is next of the connect.
	Null	Nothing but an AMF’s type marker is in.
Play Path	String	Any string is in if it is specified.

For example, Play Path is defined as some file name in FFmpeg.

Against, the result for releaseStream request is required to be next format:

Field	AMF Type	Value
Command Name	String	"_result" or "_error"
Transaction ID	Number	Same as the releaseStream request.
	Null	Nothing but an AMF’s type marker is in.

FCPublish

Tells to the partner what is same as the releaseStream request. In this case, next format is required:

Field	AMF Type	Value
Command Name	String	"FCPublish"
Transaction ID	Number	A number which is next of the releaseStream.
	Null	Nothing but an AMF’s type marker is in.
Play Path	String	(Probably) Same as the releaseStream request.

Against, the result for FCPublish request is required to be next format:

Field	AMF Type	Value
Command Name	String	"onFCPublish"

createStream

Requests to create a new Message Stream ID to the partner. In this case, next format is required:

Field	AMF Type	Value
Command Name	String	"createStream"
Transaction ID	Number	A number which is next of the FCPublish.
	Null	Nothing but an AMF’s type marker is in.

Against, the result for createStream request is required to be next format:

Field	AMF Type	Value
Command Name	String	"_result" or "_error"
Transaction ID	Number	Same as the createStream request.
	Null	Nothing but an AMF’s type marker is in.
Message ID	Number	A Message Stream ID which is assigned by the partner.

publish

Tells to the partner what is an way to publish its stream. In this case, next format is required:

Field	AMF Type	Value
Command Name	String	"publish"
Transaction ID	Number	A number which is next of the createStream.
	Null	Nothing but an AMF’s type marker is in.
Publishing Name	String	A name for publishing its stream to the partner.
Publishing Type	String	Either "live", "record" or "append". See Publishing Type.

Against, results for publish request are required to be next format:

1. Stream Begin
2. onStatus

Stream Begin

This is an event message of the User Control Message. This has following data:

1. Event Type (2 bytes / 0)
2. A Message ID (4 bytes.)

onStatus

Field	AMF Type	Value
Command Name	String	"onStatus"
Transaction ID	Number	0
	Null	Nothing but an AMF’s type marker is in.
Info Object	Object	Similar to the information of connect result.

Publishing Type

The publish command requires you to specify one of “Publishing Type” in its request. Publishing Type means:

• "live"

Only streaming. Media data will never be stored.

• "record"

Media data will be stored. If publishing name duplicated, it is rewritten as a new file.

• "append"

Same as "record" excepts is appended media data if publishing name duplicated.

Every chunk has the chunk headers. See sheave_core::messages::headers about them.

After negotiation, the server receives actual audio/video data from clients. However also FLV metadata is received as the AMF (v0). The message what contains FLV metadata is called SetDataFrame.

SetDataFrame

Field	AMF Type	Value
Command Name (Probably)	String	"@setDataFrame"
Data Name	String	"onMetaData"
Data	EcmaArray	e.g. "audiocodecid", "videocodecid"

Modules

• amf
  The Action Message Formats
• headers
  The Chunk Headers

Structs

• Acknowledgement
  The message to tell that some message length has exceeded the server-side bandwidth range. Note this must be input the total message length in receiving. (it’s not bytes received.)
• Audio
• ChunkSize
  Tells a size to chunk its stream to the partner.
• Connect
  The command to tell the information that where connects from/to.
• ConnectResult
  The response message for Connect requests.
• CreateStream
  The command to request emitting a message ID to a server.
• CreateStreamResult
  The response message for CreateStream requests.
• DeleteStream
  The command to request to delete its message ID.
• FcPublish
  The command to tell the playpath. Typically, this becomes same as the releaseStream’s one.
• FcUnpublish
  This command is same as FcPublish except this requests to delete the playpath.
• InconsistentCommand
  An error means that some command name differs you expect.
• InconsistentEventType
  An error means that some event type differs you expect.
• InvalidPublishingType
  An error that some publishing type differs you expect.
• NegativeChunkSize
  An error that some chunk size is negative.
• OnFcPublish
  The response message for FcPublish requests.
• OnStatus
  The response message for Publish requests.
• PeerBandwidth
  The message to tell the client-side bandwidth. This has 2 ways of comparision by which field you specifies.
• Publish
  The command to tell publishing information.
• PublishingFailure
  An error that publishing has failed by something cause.
• ReleaseStream
  The command to tell the Play Path (e.g. something file name).
• ReleaseStreamResult
  The response message for ReleaseStream requests.
• SetDataFrame
  The message to handle something data.
• StreamBegin
  The event to tell that the stream is ready to a client.
• Video
• WindowAcknowledgementSize
  The message to tell the server-side bandwidth. Almost RTMP tools are specifying it 2500000 in bits as their defaults.

Enums

• Channel
  The IDs which are assigned every roles of chunks. This is mainly used for the BasicHeader’s chunk ID.
• EventType
  The IDs which are types of user control messages.
• LimitType

Traits

• ChunkData
  Uniforms chunk data by a channel numbers and a message type.
• Command
• UserControl
  Uniforms user control messages by an event type.

Functions

• inconsistent_command
  A utility function of constructing an InconsistentCommand error.
• inconsistent_event_type
  A utility function of constructing an InconsistentEventType error.
• invalid_publishing_type
  A utility function of constructing an InvalidPublishingType error.
• negative_chunk_size
  A utility function of constructing a NegativeChunkSize error.
• publishing_failure
  A utility function of constructing a PublishingFailure error.