Let channels joining a MeetMe conference opt out of the denoiser

For some channel drivers, specifically those that have a varying rate in the
number of audio samples, the audio quality for a MeetMe conference can be
exceedingly poor. This is due to a unilateral application of the DENOISE
function in func_speex to channels joining the conference.

The denoiser function in the speex library is initialized with the number of
audio samples in each sample that will be provided to it. If the number of
audio samples changes, the denoiser has to be thrown away and re-initialized.

While this could be worked around by removing func_speex, that doesn't help
if you actually use the denoiser with other channels on the system.

This patches does the following:
 * Checks for the presence of func_speex as opposed to codec_speex when
   determining if the DENOISE function is present (which is where the function
   is actually implemented)
 * Adds an option to MeetMe 'n' that causes the denoiser to not be applied
   to a channel when it joins. This keeps the current behavior the default, but
   let's users disable the denoiser if it causes problems on their system.

Review: https://reviewboard.asterisk.org/r/2358

(closes issue AST-1062)
Reported by: Thomas Arimont
........

Merged revisions 382227 from http://svn.asterisk.org/svn/asterisk/branches/1.8
........

Merged revisions 382230 from http://svn.asterisk.org/svn/asterisk/branches/11


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@382232 65c4cc65-6c06-0410-ace0-fbb531ad65f3

1 files changed, 8 insertions, 0 deletions

diff --git a/CHANGES b/CHANGES
index 906efa54b..109f4f60d 100644
--- a/CHANGES
+++ b/CHANGES
@@ -73,6 +73,14 @@ Logging
  * Added the 'queue_log_realtime_use_gmt' option to have timestamps in GMT
    for realtime queue log entries.
 
+MeetMe
+-------------------
+* Added the 'n' option to MeetMe to prevent application of the DENOISE function
+  to a channel joining a conference. Some channel drivers that vary the number
+  of audio samples in a voice frame will experience significant quality problems
+  if a denoiser is attached to the channel; this option gives them the ability
+  to remove the denoiser without having to unload func_speex.
+
 Queue
 -------------------
  * Add queue available hint.  exten => 8501,hint,Queue:markq_avail