ILMFMpgSourceCallback Interface

The ILMFMpgSourceCallback interface is a user-defined interface. It must be registered by setting the ILMFMpgSource::CallbackObj property. Once you do this, the LEAD MPEG-2 media source will call its members.

Data types:

FileTypeConstants

typedef enum FileTypeConstants 
{ 
   Mpeg2_Other_Stream, /* A stream other than MPEG-2 Program or Transport. This is most likely a Raw data stream */ 
   Mpeg2_Program_Stream, /* MPEG-2 Program or MPEG-1 Systems stream */ 
   Mpeg2_Transport_Stream, /* MPEG-2 Transport stream */ 
} FileTypeConstants; 

PTSTypeConstants

typedef enum PTSTypeConstants 
{ 
   PTS_Invalid = 0, /* The PTS value is invalid because this sample does not have a PTS timestamp */ 
   PTS_Calculated, /* The PTS value is an approximation calculated by the demux. This sample does not contain a PTS timestamp */ 
   PTS_Valid /* The PTS value is correct and was obtained from the file */ 
} PTSTypeConstants; 

DataFlagConstants

typedef enum DataFlagConstants 
{ 
   DataFlag_BeginSample = 1, /* This packet is the beginning of a private data sample */ 
   DataFlag_EndSample = 2, /* This packet is the end of a private data sample */ 
   DataFlag_IsKLV = 4, /* The buffer seems to be KLV data */ 
   DataFlag_IsAscii = 8, /* The buffer seems to be Ascii data */ 
   DataFlag_IsBinary = 0x10, /* The buffer is binary data */ 
} DataFlagConstants; 

EventNotificationConstants

typedef enum EventNotificationConstants 
{ 
   EVENTTYPE_REBUILDNEEDED = 1, /* The stream has changed (the number of streams and the compression might have changed). The graph needs to be rebuilt */ 
   EVENTTYPE_CORRUPTEDPACKET = 2, /* A corrupted packet has been discarded */ 
} EventNotificationConstants; 

Interface methods:

HRESULT DataAvailable(VARIANT *pData, long lDataSize, FileTypeConstants fileType, long streamPID, long streamType, PTSTypeConstants PTSType, double PTS, long flags);

Parameters

Description

This method is called to enumerate the private data packets present in the file. There can be more than one private data stream in the file and you should use streamPID to distinguish between the various streams. This chunk might be a portion of a private data packet. Use the Flags value to determine whether this packet is:

• a whole packet (DataFlag_BeginSample and DataFlag_EndSample are both set) or

• the beginning (only DataFlag_BeginSample is set) or

• the middle (neither DataFlag_BeginSample or DataFlag_EndSample is set)

• the end (only DataFlag_EndSample is set)

If the private data stream is of KLV type (that is, if Flags has DataFlag_IsKLV set), then each packet contains a list of KLV keys and subkeys. In this case, we recommend you use ILMMpgDmx::GetKlvParser to obtain an ILMKlvParser interface. You can use the ILMKlvParser interface to enumerate all the KLV keys present in a packet. For more information on KLV keys and format, see SMPTE 336M-2001.

You can examine Flags to see if the data seems to be:

• KLV (DataFlag_IsKLV is set)

• Ascii (DataFlag_IsAscii is set)

• Binary (DataFlag_IsBinary is set)

The demux estimates the type of data based on its contents. If you believe this estimation is wrong, you can interpret the data any way you want.

Returns

S_OK if successful.

< 0 if you want to indicate an error situation and abort the playback or conversion.

HRESULT EventNotification(EventNotificationConstants lEventType, double Param1, double Param2);

Parameters

Description

This method is called when certain events occur. The following events are currently defined:

EVENTTYPE_REBUILDNEEDED the compression or the number or type of streams present have changed and that you need to rebuild the graph. This event is usually sent while you are streaming. If you are using LEADTOOLS Multimedia, you rebuild the graph by calling put_FileName with the same input URL. This event has no parameters (lParam1 and lParam2 should be ignored).

EVENTTYPE_CORRUPTEDPACKET a corrupted packet has been discarded. lParam1 = PTS timestamp of the packet which was discarded. lParam2 = should be ignored

Returns

S_OK if successful.

S_FALSE if you want the demux to ask the multimedia toolkit to automatically rebuild the graph. This is valid only for the EVENTTYPE_REBUILDNEEDED event notification.

< 0 if you want to indicate an error situation and abort the playback or conversion.