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Standard PJMEDIA object signatures. More...

Macros

#define PJMEDIA_SIGNATURE(a, b, c, d)   PJMEDIA_FOURCC(d,c,b,a)
 
#define PJMEDIA_SIG_CLASS_CODEC(b, c, d)   PJMEDIA_SIGNATURE('C',b,c,d)
 
#define PJMEDIA_SIG_IS_CLASS_CODEC(sig)   ((sig) >> 24 == 'C')
 
#define PJMEDIA_SIG_CLASS_AUD_CODEC(c, d)   PJMEDIA_SIG_CLASS_CODEC('A',c,d)
 
#define PJMEDIA_SIG_IS_CLASS_AUD_CODEC(s)   ((s)>>24=='C' && (((s)>>16)&0xff)=='A')
 
#define PJMEDIA_SIG_CLASS_VID_CODEC(c, d)   PJMEDIA_SIG_CLASS_CODEC('V',c,d)
 
#define PJMEDIA_SIG_IS_CLASS_VID_CODEC(sig)   ((s)>>24=='C' && (((s)>>16)&0xff)=='V')
 
#define PJMEDIA_SIG_VID_CODEC_FFMPEG   PJMEDIA_SIG_CLASS_VID_CODEC('F','F')
 
#define PJMEDIA_SIG_CLASS_PORT(b, c, d)   PJMEDIA_SIGNATURE('P',b,c,d)
 
#define PJMEDIA_SIG_IS_CLASS_PORT(sig)   ((sig) >> 24 == 'P')
 
#define PJMEDIA_SIG_CLASS_PORT_AUD(c, d)   PJMEDIA_SIG_CLASS_PORT('A',c,d)
 
#define PJMEDIA_SIG_IS_CLASS_PORT_AUD(s)   ((s)>>24=='P' && (((s)>>16)&0xff)=='A')
 
#define PJMEDIA_SIG_PORT_BIDIR   PJMEDIA_SIG_CLASS_PORT_AUD('B','D')
 
#define PJMEDIA_SIG_PORT_CONF   PJMEDIA_SIG_CLASS_PORT_AUD('C','F')
 
#define PJMEDIA_SIG_PORT_CONF_PASV   PJMEDIA_SIG_CLASS_PORT_AUD('C','P')
 
#define PJMEDIA_SIG_PORT_CONF_SWITCH   PJMEDIA_SIG_CLASS_PORT_AUD('C','S')
 
#define PJMEDIA_SIG_PORT_ECHO   PJMEDIA_SIG_CLASS_PORT_AUD('E','C')
 
#define PJMEDIA_SIG_PORT_MEM_CAPTURE   PJMEDIA_SIG_CLASS_PORT_AUD('M','C')
 
#define PJMEDIA_SIG_PORT_MEM_PLAYER   PJMEDIA_SIG_CLASS_PORT_AUD('M','P')
 
#define PJMEDIA_SIG_PORT_NULL   PJMEDIA_SIG_CLASS_PORT_AUD('N','U')
 
#define PJMEDIA_SIG_PORT_RESAMPLE   PJMEDIA_SIG_CLASS_PORT_AUD('R','E')
 
#define PJMEDIA_SIG_PORT_SPLIT_COMB   PJMEDIA_SIG_CLASS_PORT_AUD('S','C')
 
#define PJMEDIA_SIG_PORT_SPLIT_COMB_P   PJMEDIA_SIG_CLASS_PORT_AUD('S','P')
 
#define PJMEDIA_SIG_PORT_STEREO   PJMEDIA_SIG_CLASS_PORT_AUD('S','R')
 
#define PJMEDIA_SIG_PORT_STREAM   PJMEDIA_SIG_CLASS_PORT_AUD('S','T')
 
#define PJMEDIA_SIG_PORT_TONEGEN   PJMEDIA_SIG_CLASS_PORT_AUD('T','O')
 
#define PJMEDIA_SIG_PORT_WAV_PLAYER   PJMEDIA_SIG_CLASS_PORT_AUD('W','P')
 
#define PJMEDIA_SIG_PORT_WAV_PLAYLIST   PJMEDIA_SIG_CLASS_PORT_AUD('W','Y')
 
#define PJMEDIA_SIG_PORT_WAV_WRITER   PJMEDIA_SIG_CLASS_PORT_AUD('W','W')
 
#define PJMEDIA_SIG_CLASS_PORT_VID(c, d)   PJMEDIA_SIG_CLASS_PORT('V',c,d)
 
#define PJMEDIA_SIG_IS_CLASS_PORT_VID(s)   ((s)>>24=='P' && (((s)>>16)&0xff)=='V')
 
#define PJMEDIA_SIG_PORT_VID_AVI_PLAYER   PJMEDIA_SIG_CLASS_PORT_VID('A','V')
 
#define PJMEDIA_SIG_PORT_VID_STREAM   PJMEDIA_SIG_CLASS_PORT_VID('S','T')
 
#define PJMEDIA_SIG_PORT_VID_TEE   PJMEDIA_SIG_CLASS_PORT_VID('T','E')
 
#define PJMEDIA_SIG_CLASS_VID_DEV(c, d)   PJMEDIA_SIGNATURE('V','D',c,d)
 
#define PJMEDIA_SIG_IS_CLASS_VID_DEV(s)   ((s)>>24=='V' && (((s)>>16)&0xff)=='D')
 
#define PJMEDIA_SIG_VID_DEV_COLORBAR   PJMEDIA_SIG_CLASS_VID_DEV('C','B')
 
#define PJMEDIA_SIG_VID_DEV_SDL   PJMEDIA_SIG_CLASS_VID_DEV('S','D')
 
#define PJMEDIA_SIG_VID_DEV_V4L2   PJMEDIA_SIG_CLASS_VID_DEV('V','2')
 
#define PJMEDIA_SIG_VID_DEV_DSHOW   PJMEDIA_SIG_CLASS_VID_DEV('D','S')
 
#define PJMEDIA_SIG_VID_DEV_QT   PJMEDIA_SIG_CLASS_VID_DEV('Q','T')
 
#define PJMEDIA_SIG_VID_DEV_IOS   PJMEDIA_SIG_CLASS_VID_DEV('I','P')
 
#define PJMEDIA_SIG_CLASS_VID_OTHER(c, d)   PJMEDIA_SIGNATURE('V','O',c,d)
 
#define PJMEDIA_SIG_IS_CLASS_VID_OTHER(s)   ((s)>>24=='V' && (((s)>>16)&0xff)=='O')
 
#define PJMEDIA_SIG_VID_CONF   PJMEDIA_SIG_CLASS_VID_OTHER('C','F')
 
#define PJMEDIA_SIG_VID_PORT   PJMEDIA_SIG_CLASS_VID_OTHER('P','O')
 
#define PJMEDIA_SIG_CLASS_APP(b, c, d)   PJMEDIA_SIGNATURE('A',b,c,d)
 
#define PJMEDIA_SIG_IS_CLASS_APP(s)   ((s)>>24=='A')
 

Typedefs

typedef pj_uint32_t pjmedia_obj_sig
 

Functions

const char * pjmedia_sig_name (pjmedia_obj_sig sig, char buf[])
 

Detailed Description

Object signature is a 32-bit integral value similar to FOURCC to help identify PJMEDIA objects such as media ports, transports, codecs, etc. There are several uses of this signature, for example a media port can use the port object signature to verify that the given port instance is the one that it created, and a receiver of Event Framework can use the signature of the publisher to know which object emitted the event.

The 32-bit value of an object signature is generated by the following macro:

  #define PJMEDIA_SIGNATURE(a,b,c,d)    (a<<24 | b<<16 | c<<8 | d)
* 

The following convention is used to maintain order to the signature values so that application can make use of it more effectively, and to avoid conflict between the values themselves. For each object type or class, a specific prefix will be assigned as signature, and a macro is created to build a signature for such object:

   Class               Signature  Signature creation and test macros
   ---------------------------------------------------------------
   Codec                Cxxx       PJMEDIA_SIG_CLASS_CODEC(b,c,d)
                           PJMEDIA_SIG_IS_CLASS_CODEC(sig)

   Audio codec  CAxx       PJMEDIA_SIG_CLASS_AUD_CODEC(c,d)
                           PJMEDIA_SIG_IS_CLASS_AUD_CODEC(sig)

   Video codec  CVxx       PJMEDIA_SIG_CLASS_VID_CODEC(c,d)
                           PJMEDIA_SIG_IS_CLASS_VID_CODEC(sig)

   Media port           Pxxx       PJMEDIA_SIG_CLASS_PORT(b,c,d)
                           PJMEDIA_SIG_IS_CLASS_PORT(sig)

   Audio media port    PAxx        PJMEDIA_SIG_CLASS_PORT_AUD(c,d)
                           PJMEDIA_SIG_IS_CLASS_PORT_AUD(sig)

   Video media port    PVxx        PJMEDIA_SIG_CLASS_PORT_VID(c,d)
                           PJMEDIA_SIG_IS_CLASS_PORT_VID(sig)

   Video device VDxx       PJMEDIA_SIG_CLASS_VID_DEV(c,d)
                           PJMEDIA_SIG_IS_CLASS_VID_DEV(sig)

   Video other          VOxx       PJMEDIA_SIG_CLASS_VID_OTHER(c,d)
                           PJMEDIA_SIG_IS_CLASS_VID_OTHER(sig)

   Application object   Axxx       PJMEDIA_SIG_CLASS_APP(b,c,d)
                           PJMEDIA_SIG_IS_CLASS_APP(sig)

* 

In addition, signatures created in application code should have lowercase letters to avoid conflict with built-in objects.

Macro Definition Documentation

◆ PJMEDIA_SIGNATURE

#define PJMEDIA_SIGNATURE (   a,
  b,
  c,
 
)    PJMEDIA_FOURCC(d,c,b,a)

Macro to generate signature from four ASCII letters.

◆ PJMEDIA_SIG_PORT_VID_AVI_PLAYER

#define PJMEDIA_SIG_PORT_VID_AVI_PLAYER   PJMEDIA_SIG_CLASS_PORT_VID('A','V')

AVI player signature.

Typedef Documentation

◆ pjmedia_obj_sig

Type to store object signature.

Function Documentation

◆ pjmedia_sig_name()

const char* pjmedia_sig_name ( pjmedia_obj_sig  sig,
char  buf[] 
)

A utility function to convert signature to four letters string.

Parameters
sigThe signature value.
bufBuffer to store the string, which MUST be at least five bytes long.
Returns
The string.

References PJ_INLINE, and pjmedia_fourcc_name().

 


PJMEDIA small footprint Open Source media stack
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