On Thu, Aug 20, 2009 at 1:16 PM, Thomas Falk<thfalk at gmail.com> wrote: > Hello, > > I have send this some time ago, but got no answer and nothing happend. > It happened sometimes (more often lately). :) I just fixed this in http://trac.pjsip.org/repos/ticket/952 Thanks! Benny > I'm using an extended header in the rtp transfer of audio data. As I > have found, the code in > the function pjmedia_rtp_decode_rtp (in pjmedia/src/pjmedia/rtp.c) > calculates the size of the extended header in the wrong way. > > The following code calculates the offset of the payload after the > extended header: > > Line 169: > ? /* Adjust offset if RTP extension is used. */ > ? if ((*hdr)->x) { > ? ? ? pjmedia_rtp_ext_hdr *ext = (pjmedia_rtp_ext_hdr*) > ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? (((pj_uint8_t*)pkt) + offset); > ? ? ? offset += (pj_ntohs(ext->length) * sizeof(pj_uint32_t)); > ? } > > According to RFC 3550 the length of the extended header may be 0, even > if there is an extended header. In this case the exented header > consist of the extension header (32 bit) only. > > In the above code ext->length is this length of the extended header. > If there is an extended header the offset must be calculated to at > least 1. > > Here is the patch I'm using with pjmedia-1.3, the same applies to v1.4: > > Index: ../third_party/pjproject-1.3/pjmedia/src/pjmedia/rtp.c > =================================================================== > --- ../third_party/pjproject-1.3/pjmedia/src/pjmedia/rtp.c ? ? ?(revision 4031) > +++ ../third_party/pjproject-1.3/pjmedia/src/pjmedia/rtp.c ? ? ?(working copy) > @@ -170,7 +170,7 @@ > ? ? if ((*hdr)->x) { > ? ? ? ?pjmedia_rtp_ext_hdr *ext = (pjmedia_rtp_ext_hdr*) > ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?(((pj_uint8_t*)pkt) + offset); > - ? ? ? offset += (pj_ntohs(ext->length) * sizeof(pj_uint32_t)); > + ? ? ? offset += ((pj_ntohs(ext->length)+1) * sizeof(pj_uint32_t)); > ? ? } > > Best regards, > > Thomas Falk > > _______________________________________________ > Visit our blog: http://blog.pjsip.org > > pjsip mailing list > pjsip at lists.pjsip.org > http://lists.pjsip.org/mailman/listinfo/pjsip_lists.pjsip.org >
