Table of Contents
This document defines the IP protocol used by Rivendell for real-time communication between different modules and/or hosts. Messages are sent by means of multicast UDP packets to port 20539. The IPv4 multicast group address used is defined the in the SYSTEM.NOTIFICATION_ADDRESS database field.
Update messages are textual, with individual fields delimited by the ASCII SPACE character. They are formatted as follows:
keyword
arg1
arg2
[...]
where keyword defines the class of message.
The following classes are defined:
Signals a change to a Rivendell database object.
RDCatch state changes.
Notification messages use the following format:
NOTIFY type
action
id
type
The database object type to which the message pertains.
action
The action being reported. The following actions are defined:
The referenced object has just been added to the database.
The referenced object has just been deleted from the database.
The reference object has just been modified in the database.
id
Unique id of the object.
The following database object types are defined:
Table 1. Cart Fields
| Field | Value |
| Database Field | CART.NUMBER |
| Type | CART |
| Id Data Type | Unsigned Integer |
| RDNotification::Type Value | RDNotification::CartType [1] |
Table 2. Log Fields
| Field | Value |
| Database Field | LOGS.NAME |
| Type | LOG |
| Id Data Type | String |
| RDNotification::Type Value | RDNotification::LogType [2] |
Table 3. Pypad Instance Fields
| Field | Value |
| Database Field | PYPAD_INSTANCES.ID |
| Type | PYPAD |
| Id Data Type | Integer |
| RDNotification::Type Value | RDNotification::PypadType [3] |
Table 4. Dropbox Instance Fields
| Field | Value |
| Database Field | STATIONS.NAME |
| Type | DROPBOX |
| Id Data Type | String |
| RDNotification::Type Value | RDNotification::DropboxType [4] |
Table 5. RDCatch Event Fields
| Field | Value |
| Database Field | RECORDINGS.ID |
| Type | CATCH_EVENT |
| Id Data Type | Integer |
| RDNotification::Type Value | RDNotification::CatchEventType [5] |
Table 6. RSS Feed Item Fields
| Field | Value |
| Database Field | PODCASTS.ID |
| Type | FEED_ITEM |
| Id Data Type | Unsigned Integer |
| RDNotification::Type Value | RDNotification::FeedItemType [6] |
Table 7. RSS Feed Fields
| Field | Value |
| Database Field | FEEDS.KEY_NAME |
| Type | FEED |
| Id Data Type | String |
| RDNotification::Type Value | RDNotification::FeedType [7] |
RDCatch messages use the following format:
CATCH orig-hostname
operation
arg1
[...]
orig-hostname
The name of the host originating the message. From STATIONS.NAME.
operation
The RDCatch operation. See the list below.
Emitted by rdcatchd(8) every time a 'Cut Event' ['CE'] RML is processed.
Table 10. RDCatch Event Fields
| Field | Offset | Value |
| Keyword | 0 | CATCH |
| Originating Hostname | 1 | String, from STATIONS.NAME |
| Operation | 2 | Integer. 1 [RDCatchEvent::DeckEventProcessedOp] |
| Deck Channel | 3 | Integer. Record decks have values in the range 1-127, while play decks have values in the range 128-254. |
| Event Number | 4 | Integer. The value of CUT_EVENTS.NUMBER. |
Emitted by rdcatch(1) at startup to request the current status of all decks.
Table 11. RDCatch Event Request Fields
| Field | Offset | Value |
| Keyword | 0 | CATCH |
| Originating Hostname | 1 | String, from STATIONS.NAME |
| Operation | 2 | Integer. 2 [RDCatchEvent::DeckStatusQueryOp] |
Emitted by rdcatchd(8) whenever the status of a deck changes, or as a set in response to a request. (See Table 11, “RDCatch Event Request Fields”).
Table 12. RDCatch Event Response Fields
| Field | Offset | Value |
| Keyword | 0 | CATCH |
| Originating Hostname | 1 | String, from STATIONS.NAME |
| Operation | 2 | Integer. 3 [RDCatchEvent::DeckStatusResponseOp] |
| Deck Channel | 3 | Integer. Record decks have values in the range 1-127, while play decks have values in the range 128-254. |
| Status | 4 | Integer. Current status of the specified deck. See the section called “Deck Status Codes” for code point values. |
| Event ID | 5 | Unsigned Integer, from RECORDINGS.ID or 0 if deck is inactive. |
| Cart Number | 6 | Unsigned Integer, from CART.NUMBER or 0 if deck status is not 3 [Active]. |
| Cut Number | 7 | Integer, from cut part of CUTS.CUTNAME or 0 if deck status is not 3 [Active]. |
Emitted by rdadmin(1) to trigger a reload of the record and play-out deck parameters.
Table 14. RDCatch Reload Decks Fields
| Field | Offset | Value |
| Keyword | 0 | CATCH |
| Originating Hostname | 1 | String, from STATIONS.NAME |
| Operation | 2 | Integer. 7 [RDCatchEvent::ReloadDecksOp] |
| Target Hostname | 3 | String, from STATIONS.NAME |
Emitted by rdcatchd(8) to update audio meter levels for active record and play-out decks.
Table 15. RDCatch Send Meter Levels Fields
| Field | Offset | Value |
| Keyword | 0 | CATCH |
| Originating Hostname | 1 | String, from STATIONS.NAME |
| Operation | 2 | Integer. 8 [RDCatchEvent::SendMeterLevelsOp] |
| Meter Entry | 3 | String, chan:left-lvl:right-lvl |
Emitted by rdcatch(1) to turn a deck input monitor on or off.
Table 16. RDCatch Set Input Monitor Fields
| Field | Offset | Value |
| Keyword | 0 | CATCH |
| Originating Hostname | 1 | String, from STATIONS.NAME |
| Operation | 2 | Integer. 5 [RDCatchEvent::SetInputMonitorOp] |
| Target Hostname | 3 | String, from STATIONS.NAME |
| Deck Channel | 4 | Integer. Record decks have values in the range 1-127, while play decks have values in the range 128-254. |
| State | 5 | Boolean. 0=False, 1=True. |
Emitted by rdcatchd(8) to signal change of a deck input monitor.
Table 17. RDCatch Set Input Monitor Fields
| Field | Offset | Value |
| Keyword | 0 | CATCH |
| Originating Hostname | 1 | String, from STATIONS.NAME |
| Operation | 2 | Integer. 6 [RDCatchEvent::SetInputMonitorResponseOp] |
| Deck Channel | 3 | Integer. Record decks have values in the range 1-127, while play decks have values in the range 128-254. |
| State | 4 | Boolean. 0=False, 1=True. |
Emitted by rdcatch(1) to abort a Record or Play-out event.
Table 18. RDCatch Stop Deck Fields
| Field | Offset | Value |
| Keyword | 0 | CATCH |
| Originating Hostname | 1 | String, from STATIONS.NAME |
| Operation | 2 | Integer. 4 [RDCatchEvent::StopDeckOp] |
| Target Hostname | 3 | String, from STATIONS.NAME |
| Deck Channel | 4 | Integer. Record decks have values in the range 1-127, while play decks have values in the range 128-254. |