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_DISCONTINUITY	= 0,	/* A discontinuity has occurred. */ 
   EVENTTYPE_REBUILDNEEDED = ( EVENTTYPE_DISCONTINUITY + 1 ),     /* The stream has changed (the number of streams and the compression might have changed). The graph needs to be rebuilt. lParam1 is one of the RebuildReasonConstants values. */ 
   EVENTTYPE_CORRUPTEDPACKET = ( EVENTTYPE_REBUILDNEEDED + 1 ),   /* A corrupted packet has been discarded. Param1 = PTS timestamp of the packet which was discarded */ 
   EVENTTYPE_COMPRESSIONCHANGED = ( EVENTTYPE_CORRUPTEDPACKET + 1 ),/* The compression has changed */ 
   EVENTTYPE_SIZECHANGED = ( EVENTTYPE_COMPRESSIONCHANGED + 1 ),		/* The video dimensions (width x height) have changed. */ 
   EVENTTYPE_DECODINGSTOPPED = ( EVENTTYPE_SIZECHANGED + 1 ),	/* The decoding has stopped. */ 
   EVENTTYPE_ENDOFSTREAM = ( EVENTTYPE_DECODINGSTOPPED + 1 ),       /* The end of stream has been reached */ 
   EVENTTYPE_PROGRAMMAPPACKET = ( EVENTTYPE_ENDOFSTREAM + 1 ),  /* A program map packet has been received */ 
} EventNotificationConstants; 

Interface methods

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

Parameters

Value Description
pData Pointer to a variant containing the private data.
lDataSize A value that represents the size of the data contained in pData.
fileType An enumerated  value describing the format of the multiplexed stream.
streamPID A PID identifying the stream containing the private data. Use this value to distinguish between the different private data streams in the file.
streamType The type of private data stream.If the fileType is Mpeg2_Program_Stream, the streamType is one of the values in Table 2-19 of the ISO/IEC 13818-1 specification. Due to copyright restrictions, we cannot place this table here. Example: 0xBF is Private Stream 2. If the fileType is Mpeg2_Transport_Stream, the streamType is one of the values in Table 2-36 of the ISO/IEC 13818-1 specification. Due to copyright restrictions, we cannot place this table here. Example: values 0x0A through 0x0D indicate streams of type KLVA through KLVD.
PTSType Type of Presentation Time Stamp (PTS). Possible values: PTS_Invalid, PTS_Calculated, PTS_Valid
PTS Presentation Time Stamp indicates the time when this data was generated. The PTS should be ignored if PTSType is set to PTS_Invalid.
Flags One or more DataFlagConstants enumeration values or-ed together.

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:

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:

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

lEventType

Type of event. Possible values are:

Value Meaning
EVENTTYPE_REBUILDNEEDED [0x0001] Indicates that the compression, video size or number of streams has changed and the graph needs to be rebuilt. Return S_OK if your program rebuilds the graph or S_FALSE if you want the demux to tell the MM toolkit to rebuild the graph. lParam1 and lParam2 are not used and should be ignored.
EVENTTYPE_CORRUPTEDPACKET [0x0002] Indicates a corrupted packet has been discarded. lParam1 = PTS timestamp of the packet which was discarded. lParam2 is unused and should be ignored.

Param1

First parameter. The value depends on the type of event. This is not used right now and is reserved for future events.

Param2

Second parameter. The value depends on the type of event. This is not used right now and is reserved for future events.  

Description

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

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.

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