[asterisk-users] DTMF not completely muted

[Michael Smith]

Kevin P. Fleming <kpfleming <at> digium.com> writes:

> Michael Smith wrote:
> 
> > When the Dahdi driver detects DTMF, it seems it's not muting the first
> > 5-15 ms and sometimes the last 2-10 ms of the DTMF tone.
> 
> The blip at the beginning is expected; the DTMF detector won't trigger
> until it has seen a long enough continuous tone to recognize it, and
> then it will begin muting the audio. The only way around this would be
> to artificially delay the audio stream by 20-40ms to accommodate the
> muting, but most people would not enjoy the additional latency this
> would create.

This makes sense, so I'm looking for a way to post-process the voicemail
greetings because it's kind of ugly to leave the blips in there.

Although it is odd that it doesn't cut the recording as soon as the detector
triggers. If it did, the wav file would end after the first blip, and there
would never be a second blip. It seems like it waits for button-up to stop the
recording.

Mike