[asterisk-bugs] [Asterisk 0010741]: [patch] AMR NB pass-through

[noreply at bugs.digium.com]

A NOTE has been added to this issue. 
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http://bugs.digium.com/view.php?id=10741 
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Reported By:                klaus3000
Assigned To:                
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Project:                    Asterisk
Issue ID:                   10741
Category:                   Core-General
Reproducibility:            always
Severity:                   minor
Priority:                   normal
Status:                     new
Asterisk Version:            SVN 
SVN Branch (only for SVN checkouts, not tarball releases):  trunk 
SVN Revision (number only!): 82546 
Disclaimer on File?:        N/A 
Request Review:              
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Date Submitted:             09-17-2007 08:30 CDT
Last Modified:              09-18-2007 02:25 CDT
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Summary:                    [patch] AMR NB pass-through
Description: 
This adds pass-through of AMR narrow band to Asterisk's core, chan_sip and
rtp.

Further, a format_amrnb.c was added which should store in RFC conform AMR
files.
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---------------------------------------------------------------------- 
 klaus3000 - 09-18-07 02:25  
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Hi again!

I've just read the RFC again to find out how to announce multiple AMR
capabilities. For example, if Asterisk supports AMR octet-aligned AND AMR
bandwidth efficient mode it has to add 2 entries to the SDP, eg:

m=audio 49120 RTP/AVP 97 98
a=rtpmap:97 AMR/8000
a=rtpmap:98 AMR/8000
a=fmtp:98 octed-aligned=1

Thus, we have 2 possibilities:
1. Make different AST_FORMATs for the different AMR variants
2. Add a subsubtype (or a void *priv) member to ast_frame which can be
used by codecs to store private/internal data

Solution 2 would be more flexible but does not allow transcoding from one
AMR mode to another AMR mode as Asterisk sees only a single codec. 

Issue History 
Date Modified   Username       Field                    Change               
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09-18-07 02:25  klaus3000      Note Added: 0070719                          
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