[asterisk-dev] Empty recordings with length of 4 seconds

[Steve Blair]

Marcus:

 I've seen this too but I was never quite sure about the source of the 
problem. In each case the INVITE is received by Asterisk however no 
greeting is played and a 4 second empty message is produced. What/where 
exactly is the source of this problem?

Thanks,Steve

Marcus Hunger wrote:

>Recently I found some voicemail-recordings in my voicebox, that claimed to be 
>4 seconds long, but the .wav-files were almost empty (a wave-header was 
>there). I traced the problem to app.c, which threw a warning "Apr 7 18:19:12 
>WARNING[30378] app.c: No audio available on SIP/*********" followed by "user 
>hungup".
> 
>ast_play_and_record() returns the duration of these failed recordings which is 
>4 seconds. 
> 
>these 4 seconds come from the following code:
> 
> res = ast_waitfor(chan, 2000);
> if (!res) {
>    ast_log(LOG_DEBUG, "One waitfor failed, trying another\n");
>    /* Try one more time in case of masq */
>    res = ast_waitfor(chan, 2000);
>    if (!res) {
>       ast_log(LOG_WARNING, "No audio available on %s??\n", chan->name);
>       res = -1;
>    }
> }
> 
>so the check for audio-availability lasts 4 seconds and then the function 
>returns as if the user has hungup normally.
> 
>I created a patch so that ast_play_and_record() decreases the recording's 
>duration by 4 seconds.
>
>For the patch and the start of the discussion, look here:
>http://bugs.digium.com/view.php?id=6911
>
>The "No audio"-condition is different from silence and means that asterisk 
>didn't receive audio-data for a specific amount of time, right?
>
>ast_play_and_prepend suffers from the same problem and should be handle the 
>same way.
>
>Marcus
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