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1.8.0-rc2_crypto_offer.diff 2010-10-15 716 Bytes
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1.8.0-rc2_asterisk_amr_patch.diff 2010-10-15 30.4 kB
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README 2010-10-15 1.3 kB
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This patch has been created with purpose to evaluate AMR-NB codec with asterisk 1.8.0 RC2.
The patch also force the SDP to offer octet-aligned mode to 1.

To download the AMR-NB codec from 3GPP site follow this link  :
http://www.3gpp.org/ftp/Specs/archive/26_series/26.104/26104-700.zip


Installation 

Go to asterisk source-code amr codec folder  (cd asterisk-1.8.0-rc2/codecs/amr/) then :

wget http://www.3gpp.org/ftp/Specs/archive/26_series/26.104/26104-700.zip1
unzip -j 26104-700.zip
unzip -j 26104-700_ANSI_C_source_code.zip

go back to asterisk-1.8.0-rc2/ folder and  re-compile Asterisk (make;make install)

Considering to use mobile client over GPRS network a way to save bandwidth can be to use
Crypto Offer of RTP HMAC_SHA1_32  packet instead of HMAC_SHA1_80, 
This will  120 bytes/m.

--- original/asterisk-1.8.0-rc2/channels/sip/sdp_crypto.c	2010-06-08 07:29:08.000000000 +0200
+++ tmp/asterisk-1.8.0-rc2/channels/sip/sdp_crypto.c	2010-10-15 21:10:50.000000000 +0200
@@ -287,7 +287,7 @@ int sdp_crypto_process(struct sdp_crypto
 int sdp_crypto_offer(struct sdp_crypto *p)
 {
 	char crypto_buf[128];
-	const char *crypto_suite = "AES_CM_128_HMAC_SHA1_80"; /* Crypto offer */
+	const char *crypto_suite = "AES_CM_128_HMAC_SHA1_32"; /* Crypto offer */
 
 	if (p->a_crypto) {
 		ast_free(p->a_crypto);
Source: README, updated 2010-10-15