GAMBAS BOOK 3.19.5

The MediaMessage class cannot be created. The class behaves like a read-only array and can be enumerated with the keyword pair 'For Each'. This returns the value that is linked to a key name stored in the message:

Dim hMediaMessage As MediaMessage
Dim vValue As Variant

vValue = hMediaMessage [ Name As String ]

All values stored in a message are enumerated in this way:

Dim hMediaMessage As MediaMessage
Dim vValue As Variant

For Each vValue In hMediaMessage
    ...
Next

The MediaMessage class has these five properties:

Table 23.9.6.1.1 : Properties of the MediaMessage class

The MediaMessage class has the following constants:

• AsyncDone, AsyncStart, Buffering, ClockLost, DurationChanged, Element, Eos
• Error, Info, Latency, NewClock, Progress, Qos, RequestState, SegmentDone, Start
• StateAsync, StateChanged, Status, StepDone, StepStart, StreamStart, StreamStatus
• Tag, Toc, Warning

You can find the integer values associated with the constants on the website https://gambaswiki.org/wiki/comp/gb.media/mediamessage

In the following source code section, the messages are read from the data stream and displayed in the console of the IDE:

Public Sub hPipeline_Event(Message As MediaMessage)
 
  Dim vVariant As Variant
 
  Print "MESSAGE.NAME = "; Message.Name
  Print "------------------------------------------"
  For Each vVariant In Message
      Print "KEY = "; Message.Key; " -->> VALUE = "; Message[Message.Key]
  Next
  Print "------------------------------------------" 
 
End

This is an excerpt of the continuously read messages - without filters:

...
------------------------------------------
MESSAGE.NAME = GstMessageStateChanged
------------------------------------------
KEY = old-state -->> VALUE = null
KEY = new-state -->> VALUE = ready
KEY = pending-state -->> VALUE = paused
------------------------------------------
MESSAGE.NAME = GstMessageNeedContext
------------------------------------------
KEY = context-type -->> VALUE = gst.soup.session
------------------------------------------
MESSAGE.NAME = GstMessageHaveContext
------------------------------------------
KEY = context -->> VALUE =
------------------------------------------
MESSAGE.NAME = GstMessageStreamStatus
------------------------------------------
KEY = type -->> VALUE = create
KEY = owner -->> VALUE =
KEY = object -->> VALUE =
------------------------------------------
MESSAGE.NAME = GstMessageStateChanged
------------------------------------------
KEY = old-state -->> VALUE = ready
KEY = new-state -->> VALUE = paused
KEY = pending-state -->> VALUE = void-pending
------------------------------------------
MESSAGE.NAME = GstMessageStreamStatus
------------------------------------------
KEY = type -->> VALUE = enter
KEY = owner -->> VALUE =
KEY = object -->> VALUE =
------------------------------------------
MESSAGE.NAME = http-headers
------------------------------------------
KEY = uri -->> VALUE = http://icecast.ndr.de/ndr/ndr1wellenord/kiel/mp3/128/stream.mp3
KEY = http-status-code -->> VALUE = 200
KEY = redirection-uri -->> VALUE = http://f141.rndfnk.com/ard/ndr/ndr1wellenord/kiel/mp3/128/stream.mp3?cid=01FBQ1T52FB81EDG99JE36KN5J&sid=2aluMgAc2xEGJVo7hUwbHeTv3gl&token=MUkpI-R3L45S55UKaBf6NJtcAZ8ysRIr3sg9wLhh3DY&tvf=6CRHShweqRdmMTQxLnJuZGZuay5jb20
KEY = request-headers -->> VALUE =
KEY = response-headers -->> VALUE =
------------------------------------------
...

In the alternative source code section, a message filter with a freely defined message name is used → Message.Name = GstMessageStateChanged:

Public Sub hPipeline_Event(Message As MediaMessage)
 
    Dim i As Integer
 
    If Message.Name = "GstMessageStateChanged" Then
       Print
       Print "MESSAGE.NAME = "; Message.Name
       Print "--------------------------------------"
    Endif
    For i = 0 To Message.Count - 1
        If Message.Name = "GstMessageStateChanged" Then
           Print "KEY = "; Message.Keys[i]; " -->> VALUE = "; Message[Message.Keys[i]]
        Endif
    Next
 
End

Here is an excerpt of the continuously read messages - with filter:

...
MESSAGE.NAME = GstMessageStateChanged
--------------------------------------
KEY = old-state -->> VALUE = null
KEY = new-state -->> VALUE = ready
KEY = pending-state -->> VALUE = paused

MESSAGE.NAME = GstMessageStateChanged
--------------------------------------
KEY = old-state -->> VALUE = ready
KEY = new-state -->> VALUE = paused
KEY = pending-state -->> VALUE = void-pending
...