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you have a recording on a menu that has been stored as GSM, you would need to use
a format interpreter to play that recording to any channels not using the GSM codec.4
If you store a recording in several formats simultaneously (such as WAV, GSM, etc.),
Asterisk will determine the least costly format5 to use when a channel needs to play
that recording.
4 It is partly for this reason that we do not recommend the default GSM format for system recordings. WAV
recordings will sound better and use fewer CPU cycles.
5 Some codecs will impose a significant load on the CPU, so much so that a system that might support several
hundred channels without transcoding will only handle a few dozen when transcoding is in use.
Modules
|
15
Table 2-7. Format interpreters
Name
format_g729
format_gsm
format_h264
format_ilbc
Plays files stored in
G.729: .g729
RPE-LTP (original GSM codec): .gsm
H.264 video: .h264
Internet Low Bitrate Codec: .ilbc
Graphic file: .jpeg, .jpg
format_jpeg
format _ogg_ vorbis Ogg container: .ogg
format_pcm
format_siren14
format_siren7
format_sln
format_vox
format_wav
format_wav_gsm
Various Pulse-Coded Modulation formats: .alaw, .al, .alw, .pcm, .ulaw, .ul, .mu, .ulw, .g722, .au
G.722.1 Annex C (14 kHz): .siren14
G.722.1 (7 kHz): .siren7
8-bit signed linear: .sln, .raw
.vox
.wav
GSM audio in a WAV container: .wav, .wav49
Dialplan Functions
Dialplan functions, listed in Table 2-8, complement the dialplan applications (see
“Applications” on page 11). They provide many useful enhancements to things like
string handling, time and date wrangling, and ODBC connectivity.
Table 2-8. A curated list of useful dialplan functions
Name
func_audiohook
inherit
func_blacklist
func_callcomple
tion
func_callerid
func_cdr
func_channel
func_config
func_curl
func_cut
func_db
func_devstate
func_dialgroup
func_dialplan
func_env