Note

This command just lists all codecs available in asterisk, not specifically reflecting your configuration. It does not show the codecs according to preferences or availability in a specific channel.

Which codecs you use for each channel is configured in channel configuration files. Also, see the Asterisk cli show translation cli command, that calculates time of conversion between the codecs that are installed on the system it is running on..

• Asterisk config files: Config files, including channel configuration files
• Asterisk channels: Information on Asterisk channels, i.e. SIP, IAX, MGCP etc
• Asterisk CLI: Asterisk Command line interface

asterisk -rx "core show codecs"

       INT    BINARY        HEX   TYPE       NAME   DESC

---

         1 (1 <<  0)      (0x1)  audio       g723   (G.723.1)                                                                
         2 (1 <<  1)      (0x2)  audio        gsm   (GSM)                                                                    
         4 (1 <<  2)      (0x4)  audio       ulaw   (G.711 u-law)                                                            
         8 (1 <<  3)      (0x8)  audio       alaw   (G.711 A-law)                                                            
        16 (1 <<  4)     (0x10)  audio   g726aal2   (G.726 AAL2)                                                             
        32 (1 <<  5)     (0x20)  audio      adpcm   (ADPCM)                                                                  
        64 (1 <<  6)     (0x40)  audio       slin   (16 bit Signed Linear PCM)                                               
       128 (1 <<  7)     (0x80)  audio      lpc10   (LPC10)                                                                  
       256 (1 <<  8)    (0x100)  audio       g729   (G.729A)                                                                 
       512 (1 <<  9)    (0x200)  audio      speex   (SpeeX)                                                                  
      1024 (1 << 10)    (0x400)  audio       ilbc   (iLBC)                                                                   
      2048 (1 << 11)    (0x800)  audio       g726   (G.726 RFC3551)                                                          
      4096 (1 << 12)   (0x1000)  audio       g722   (G722)                                                                   
     65536 (1 << 16)  (0x10000)  image       jpeg   (JPEG image)                                                             
    131072 (1 << 17)  (0x20000)  image        png   (PNG image)                                                              
    262144 (1 << 18)  (0x40000)  video       h261   (H.261 Video)                                                            
    524288 (1 << 19)  (0x80000)  video       h263   (H.263 Video)                                                            
   1048576 (1 << 20) (0x100000)  video      h263p   (H.263+ Video)                                                           
   2097152 (1 << 21) (0x200000)  video       h264   (H.264 Video)