(gdb) bt full
#0  0x00000000005313a3 in ast_rtp_codecs_payloads_clear (codecs=0x7fffec07ca90, 
    instance=0x0) at rtp_engine.c:416
        i = 174
#1  0x00007fffe2c907e1 in process_sdp (p=0x7fffd0013db8, req=0x7fffec09f340, 
    t38action=1) at chan_sip.c:9018
        res = 0
        start = 0
        next = 0
        iterator = 0
        type = 0 '\000'
        value = 0x0
        m = 0x0
        nextm = 0x0
        len = -1
        sessionsa = {ss = {ss_family = 52868, __ss_align = 140737153459893, 
            __ss_padding = "\000\000ip:sip\000\000\000\000\000\000\000\000\060.1\000transport\000UDP\000;tag=3", '\000' <repeats 24 times>"\377, \377\377\377", '\000' <repeats 20 times>, " \a[\232=", '\000' <repeats 18 times>}, len = 0}
        audiosa = {ss = {ss_family = 0, __ss_align = 3, 
            __ss_padding = "H\347\t\354\377\177\000\000\320\v'\232=\000\000\000\001\200\255\373\377\177\000\000\000\027\000\320\377\177\000\000\000\027\000\320\377\177\000\000\375\026\000\320\377\177\000\000\375\026\000\320\377\177\000\000\375\026\000\320\377\177\000\000\375\026\000\320\377\177\000\000\375\026\000\320\377\177\000\000\000\027\000\320\377\177", '\000' <repeats 25 times>}, len = 0}
        videosa = {ss = {ss_family = 58816, __ss_align = 0, 
            __ss_padding = "\000\000\000\000\000\000\000\000\004\255\313\342\377\177\000\000C,\003\320\377\177\000\000\065\025\000\320\377\177\000\000\020\346\t\354\377\177\000\000\246\263\320\342\377\177\000\000sip:1000@127.0.0.1\000transport=UDP\000\000\000\000\001\000\000\000\060\346\t\354\377\177\000\000\375\026\000\320\377\177\000\000\065w\321\342\377\177\000"}, len = 3489666813}
        textsa = {ss = {ss_family = 15944, __ss_align = 1, 
            __ss_padding = "\306M\202\000\000\000\000\000\340>\001\320\377\177\000\000\001\000\000\000\000\000\000\000\306M\202\000\000\000\000\000p\273&\232=\000\000\000\060\346\t\354\377\177", '\000' <repeats 18 times>, "\030\000\000\000\060\000\000\000 \350\t\354\377\177\000\000`\347\t\354\377\177\000\000\000\305\377\377\377\177\000\000\260\350\t\354\377\177\000\000ձ\313\342\377\177\000"}, len = 1}
        imagesa = {ss = {ss_family = 59089, __ss_align = 0, 
            __ss_padding = "\000\000\000\000\000\000\000\000\321\346\t\354\377\177\000\000\272\346\t\354\377\177\000\000\240\343\t\354\377\177\000\000(?\001\320\377\177\000\000\t\000\000\000\000\000\000\000\254X\270\000\000\000\000\000\265\346\t\354\377\177\000\000@\345\t\354\377\177\000\000ԙ\320\342\377\177\000\000\220>\001\320\377\177\000\000\001\000\000\000\000\000\000\000\306M\202\000\000\000\000\000\210>\001\320\377\177\000"}, len = 8}
        sa = 0x0
        vsa = 0x0
        tsa = 0x0
        isa = 0x0
        portno = -1
        vportno = -1
        tportno = -1
        udptlportno = -1
        peercapability = 0x7fffd0011fb0
        vpeercapability = 0x7fffd0013ce0
        tpeercapability = 0x7fffd00367e0
        peernoncodeccapability = 0
        vpeernoncodeccapability = 0
        tpeernoncodeccapability = 0
        newaudiortp = {pref = {formats = {{id = 0, fattr = {
                  format_attr = '\000' <repeats 127 times>, 
                  rtp_marker_bit = 0 '\000'}} <repeats 64 times>}, 
            order = '\000' <repeats 63 times>, framing = {
              0 <repeats 64 times>}}, payloads = {{asterisk_format = 0, 
              format = {id = 0, fattr = {
                  format_attr = '\000' <repeats 127 times>, 
                  rtp_marker_bit = 0 '\000'}}, 
              rtp_code = 0} <repeats 131 times>, {asterisk_format = 0, format = {
                id = 0, fattr = {format_attr = '\000' <repeats 127 times>, 
                  rtp_marker_bit = 0 '\000'}}, rtp_code = 0}, {
              asterisk_format = 0, format = {id = 0, fattr = {
                  format_attr = '\000' <repeats 127 times>, 
                  rtp_marker_bit = 0 '\000'}}, rtp_code = 0}, {
              asterisk_format = 0, format = {id = 0, fattr = {