Add functions to detect HR/FR SID frames

Add functions which check if given FR or HR frame (packed in RTP)
contains SID (SIlence Descriptor) and corresponding tests.

Related: OS#22
Change-Id: I4051e3c0d4fb9ee93d7e9e0ef4abaf9f18e227ca
Reviewed-on: https://gerrit.osmocom.org/160
Tested-by: Jenkins Builder
Reviewed-by: Harald Welte <laforge@gnumonks.org>
diff --git a/tests/codec/codec_test.ok b/tests/codec/codec_test.ok
index 0f76fef..2af7cc7 100644
--- a/tests/codec/codec_test.ok
+++ b/tests/codec/codec_test.ok
@@ -7,3 +7,9 @@
 [33/33] AMR 12,2 kbit/s (GSM-EFR), CMR: OK, FT: OK, BFI: OK, CMI: -1, STI: -1
 [21/21] AMR 7,40 kbit/s (TDMA-EFR), CMR: OK, FT: OK, BFI: OK, CMI: -1, STI: -1
 [21/21] AMR 7,40 kbit/s (TDMA-EFR), CMR: OK, FT: OK, BFI: OK, CMI: -1, STI: -1
+FR RTP payload SID test:
+FR SID ? d7 27 93 e5 e3 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 :: 1
+FR SID ? d8 a9 b5 1d da a8 82 cc ec 52 29 05 a8 c3 e3 0e b0 89 7a ee 42 ca c4 97 22 e6 9e a8 b8 ec 52 26 bd :: 0
+HR RTP payload SID test:
+HR SID ? 03 8e b6 cb ff ff ff ff ff ff ff ff ff ff :: 1
+HR SID ? 06 46 76 b1 8e 48 9a 2f 5e 4c 22 2b 62 25 :: 0