[asterisk-bugs] [JIRA] (ASTERISK-24373) Sub-second silence

[Rusty Newton (JIRA)]

     [ https://issues.asterisk.org/jira/browse/ASTERISK-24373?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Rusty Newton updated ASTERISK-24373:
------------------------------------

    Description: 
In some situations it is necessary to send at least 1 audio frame to a channel before audio can be received.  I believe it would be very helpful to add silence/20ms audio files to the standard audio distribution.  I'm unsure if other lengths would also be useful.  For my own use 20ms is enough to allow audio to start flowing in both directions.

As another thought, maybe it would be useful to have an option for Wait to play silence of arbitrary length, for example: Wait(0.02,s).  I still think adding a minimum length silent audio to the sounds distribution would be useful since an option to generate silence from Wait() is unlikely to happen in released branches.

[Edit by Rusty - Adding Corey's use case below]

My use case for this audio is in an outbound dialer using SIP through a Cisco firewall. A call is originated and processed with the following dialplan:

{noformat}
exten => s,1,Answer()
same => n,Playback(silence/20ms)
same => n,AMD()
same => n,NoOp(do stuff based on AMD results)
{noformat}

Initially I was using Wait(0.1) in place the Playback, however for reasons unknown to me this prevented the dialer from receiving any audio, and AMD() timed out with silence. I verified that the PBX which received the call was sending RTP to the correct IP immediately upon Answer, but the dialer didn't receive RTP until after it sent RTP. So I needed to add silence before running AMD, but silence/1 would be too large of a delay.


  was:
In some situations it is necessary to send at least 1 audio frame to a channel before audio can be received.  I believe it would be very helpful to add silence/20ms audio files to the standard audio distribution.  I'm unsure if other lengths would also be useful.  For my own use 20ms is enough to allow audio to start flowing in both directions.

As another thought, maybe it would be useful to have an option for Wait to play silence of arbitrary length, for example: Wait(0.02,s).  I still think adding a minimum length silent audio to the sounds distribution would be useful since an option to generate silence from Wait() is unlikely to happen in released branches.


> Sub-second silence
> ------------------
>
>                 Key: ASTERISK-24373
>                 URL: https://issues.asterisk.org/jira/browse/ASTERISK-24373
>             Project: Asterisk
>          Issue Type: Bug
>      Security Level: None
>          Components: Sounds
>    Affects Versions: SVN
>            Reporter: Corey Farrell
>            Assignee: Rusty Newton
>            Severity: Minor
>         Attachments: 20ms.ulaw
>
>
> In some situations it is necessary to send at least 1 audio frame to a channel before audio can be received.  I believe it would be very helpful to add silence/20ms audio files to the standard audio distribution.  I'm unsure if other lengths would also be useful.  For my own use 20ms is enough to allow audio to start flowing in both directions.
> As another thought, maybe it would be useful to have an option for Wait to play silence of arbitrary length, for example: Wait(0.02,s).  I still think adding a minimum length silent audio to the sounds distribution would be useful since an option to generate silence from Wait() is unlikely to happen in released branches.
> [Edit by Rusty - Adding Corey's use case below]
> My use case for this audio is in an outbound dialer using SIP through a Cisco firewall. A call is originated and processed with the following dialplan:
> {noformat}
> exten => s,1,Answer()
> same => n,Playback(silence/20ms)
> same => n,AMD()
> same => n,NoOp(do stuff based on AMD results)
> {noformat}
> Initially I was using Wait(0.1) in place the Playback, however for reasons unknown to me this prevented the dialer from receiving any audio, and AMD() timed out with silence. I verified that the PBX which received the call was sending RTP to the correct IP immediately upon Answer, but the dialer didn't receive RTP until after it sent RTP. So I needed to add silence before running AMD, but silence/1 would be too large of a delay.



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