[asterisk-bugs] [Asterisk 0014491]: [patch] DTMF blips at end of recordings in __ast_play_and_record()

[Asterisk Bug Tracker]

A NOTE has been added to this issue. 
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https://issues.asterisk.org/view.php?id=14491 
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Reported By:                asbestoshead
Assigned To:                jpeeler
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Project:                    Asterisk
Issue ID:                   14491
Category:                   Applications/General
Reproducibility:            always
Severity:                   tweak
Priority:                   normal
Status:                     assigned
Target Version:             1.6.0.12
Asterisk Version:           Older 1.6.0 
Regression:                 No 
SVN Branch (only for SVN checkouts, not tarball releases): N/A 
SVN Revision (number only!):  
Request Review:              
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Date Submitted:             2009-02-17 10:39 CST
Last Modified:              2009-07-26 10:13 CDT
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Summary:                    [patch] DTMF blips at end of recordings in
__ast_play_and_record()
Description: 
When using a channel with real in-band DTMF (e.g. Dahdi), voicemail
greetings and other recordings have remnants of the DTMF tone left at the
end. Usually it's about 5-15ms of DTMF before the Dahdi DTMF detector
kicked in, and sometimes there's an additional 5ms at the end of the tone.

The attached patch stops recording on button DOWN, not button UP; it also
trims the last 400ms from the recording in the case where it was terminated
by DTMF. I'm not 100% happy with this, but it seems to completely get rid
of noisy blips at the end of recordings a little over 50% (*) of the time,
and I haven't heard complaints about it truncating too much. I'm sort of
looking for feedback more than anything.

The patch is against 1.6.0-beta9, but it applies cleanly to 1.6.0.5.

(*) 24 out of 43 users who changed their greetings since I applied the
patch. Some of them might have retried if they heard the blip, but most
probably wouldn't notice. I didn't notice, until it was pointed out to me
-- and since then it's all I can hear :)
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 (0108232) asbestoshead (reporter) - 2009-07-26 10:13
 https://issues.asterisk.org/view.php?id=14491#c108232 
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The current patch cuts 400ms before BEGIN, so however long the beep is,
it'll be cut. It cuts 400ms before BEGIN as a compromise between wanting to
cut the most common "bounce" periods I was seeing, and not wanting to cut
speech.

I was testing with Mitel Superset 4025 phones connected to a Mitel SX-200,
connected to Asterisk 1.6.0.x by T1 E&M (Dahdi), to Asterisk 1.6.0b9 by
SIP.

The Mitel keys are bouncy, and the Dahdi DTMF detector is fairly
conservative, sosometimes it takes 400ms or longer from the instant the '#'
is hit until the tone kicks in solid enough for Dahdi to detect and
suppress it. 

Issue History 
Date Modified    Username       Field                    Change               
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2009-07-26 10:13 asbestoshead   Note Added: 0108232                          
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