codecs.conf

[speex]
; CBR encoding quality [0..10]
; used only when vbr = false
quality => 3

; codec complexity [0..10]
; tradeoff between cpu/quality
complexity => 2

; perceptual enhancement [true / false]
; improves clarity of decoded speech
enhancement => true

; voice activity detection [true / false]
; reduces bitrate when no voice detected, used only for CBR
; (implicit in VBR/ABR)
vad => true

; variable bit rate [true / false]
; uses bit rate proportionate to voice complexity
vbr => true

; available bit rate [bps, 0 = off]
; encoding quality modulated to match this target bit rate
; not recommended with dtx or pp_vad - may cause bandwidth spikes
abr => 0

; VBR encoding quality [0-10]
; floating-point values allowed
vbr_quality => 4

; discontinuous transmission [true / false]
; stops transmitting completely when silence is detected
; pp_vad is far more effective but more CPU intensive
dtx => false

; preprocessor configuration
; these options only affect Speex v1.1.8 or newer

; enable preprocessor [true / false]
; allows dsp functionality below but incurs CPU overhead
preprocess => false

; preproc voice activity detection [true / false]
; more advanced equivalent of DTX, based on voice frequencies
pp_vad => false

; preproc automatic gain control [true / false]
pp_agc => false
pp_agc_level => 8000

; preproc denoiser [true / false]
pp_denoise => false

; preproc dereverb [true / false]
pp_dereverb => false
pp_dereverb_decay => 0.4
pp_dereverb_level => 0.3

; experimental bitrate changes depending on RTCP feedback [true / false]
experimental_rtcp_feedback => false


[plc]
; for all codecs which do not support native PLC
; this determines whether to perform generic PLC
; there is a minor performance penalty for this.
; By default plc is applied only when the 2 codecs
; in a channel are different.
genericplc => true
; Apply generic plc to channels even if the 2 codecs
; are the same.  This forces transcoding via slin so
; the performance impact should be considered.
; Ignored if genericplc is not also enabled.
genericplc_on_equal_codecs => false

; Generate custom formats for formats requiring attributes.
; After defining the custom format, the name used in defining
; the format can be used throughout Asterisk in the format 'allow'
; and 'disallow' options.
;
; Example: silk8 is a predefined custom format in this config file.
; Once this config file is loaded, silk8 can be used anywhere a
; peer's codec capabilities are defined.
;
; In sip.conf 'silk8' can be defined as a capability for a peer.
; [peer1]
; type=peer
; host=dynamic
; disallow=all
; allow=silk8 ;custom codec defined in codecs.conf
;
; LIMITATIONS
; Custom formats can only be defined at startup.  Any changes to this
; file made after startup will not take into effect until after Asterisk
; is restarted.
;

; Default Custom SILK format definitions, only one custom SILK format per
; sample rate is allowed.
[silk8]
type=silk
samprate=8000
fec=true           ; turn on or off encoding with forward error correction.
                   ; On recommended, off by default.
packetloss_percentage=10   ; Estimated packet loss percentage in uplink direction.  This
                           ; affects how much redundancy is built in when using fec.
                           ; The higher the percentage, the larger amount of bandwidth is
                           ; used. Default is 0%, 10% is recommended when fec is in use.

maxbitrate=10000    ; Use the table below to make sure a useful bitrate is choosen
                    ; for maxbitrate.  If not set or value is not within the bounds
                    ; of the encoder, a default value is chosen.
                    ;
                    ;  sample rate | bitrate range
                    ;  8khz        | 5000 - 20000 bps
                    ;  12khz       | 7000 - 25000 bps
                    ;  16khz       | 8000 - 30000 bps
                    ;  24khz       | 20000- 40000 bps
                    ;
;dtx=true       ; Encode using discontinuous transmission mode or not. Turning this
                ; on will save bandwidth during periods of silence at the cost of
                ; increased computational complexity.  Off by default.

[silk12]
type=silk
samprate=12000
maxbitrate=12000
fec=true
packetloss_percentage=10;

[silk16]
type=silk
samprate=16000
maxbitrate=20000
fec=true
packetloss_percentage=10;

[silk24]
type=silk
samprate=24000
maxbitrate=30000
fec=true
packetloss_percentage=10;


; Default custom CELT codec definitions. Only one custom CELT definition is allowed
; per a sample rate.
;[celt44]
;type=celt
;samprate=44100  ; The samplerate in hz. This option is required.
;framesize=480   ; The framesize option represents the duration of each frame in samples.
                 ; This must be a factor of 2.  This option is only advertised in an SDP
                 ; when it is set.  Otherwise a default of framesize of 480 is assumed
                 ; internally

;[celt48]
;type=celt
;samprate=48000

;[celt32]
;type=celt
;samprate=32000

;============================ OPUS Section Options ============================
;
; NOTE: Accurate documentation corresponding to your downloaded version of
;       codec_opus is available from Asterisk's CLI:
;
;       *CLI> config show help codec_opus opus
;
;[opus]
;type= ; Must be of type "opus" (default: "")
;packet_loss= ; Encoder's packet loss percentage. Can be any number between 0
              ; and 100, inclusive. A higher value results in more loss
              ; resistance. (default: 0)
;complexity= ; Encoder's computational complexity. Can be any number between 0
             ; and 10, inclusive. Note, 10 equals the highest complexity.
             ; (default: 10)
;max_bandwidth= ; Encoder's maximum bandwidth allowed. Sets an upper bandwidth
                ; bound on the encoder. Can be any of the following: narrow,
                ; medium, wide, super_wide, full. (default: full)
;signal= ; Encoder's signal type. Aids in mode selection on the encoder: Can
         ; be any of the following: auto, voice, music. (default: auto)
;application= ; Encoder's application type. Can be any of the following: voip,
              ; audio, low_delay. (default: voip)
;max_playback_rate= ; Override the maximum playback rate in the offer's SDP.
                    ; Any value between 8000 and 48000 (inclusive) is valid,
                    ; however typically it should match one of the usual opus
                    ; bandwidths. (default: 48000)
;bitrate= ; Override the maximum average bitrate in the offer's SDP. Any value
          ; between 500 and 512000 is valid. The following values are also
          ; allowed: auto, max. (default: auto)
;cbr= ; Override the constant bit rate parameter in the offer's SDP. A value of
      ; 0/false/no represents a variable bit rate whereas 1/true/yes represents
      ; a constant bit rate. (default: no)
;fec= ; Override the use inband fec parameter in the offer's SDP. A value of
      ; 0/false/no represents disabled whereas 1/true/yes represents enabled.
      ; (default: yes)
;dtx= ; Override the use dtx parameter in the offer's SDP. A value of 0/false/no
      ; represents disabled whereas 1/true/yes represents enabled. (default: no)

;=============================== OPUS Examples ================================
;
;[opus]
;type=opus
;max_playback_rate=8000 ; Limit the maximum playback rate on the encoder
;fec=no ; No inband fec

;[myopus]
;type=opus
;max_bandwidth=wide ; Maximum encoded bandwidth set to wide band (0-8000 Hz
;                   ; audio bandwidth at 16Khz sample rate)
;cbr=yes ; Negotiate a constant bit rate