Discrepancy in RTP Stream Analysis Max Delta Calculation​

edit

The Marker flag is set on frame 18 so not included in the Max Delta calculations.

There is an example in the WSUG (Figure 9.9. The “RTP Stream Analysis” window) that shows two Marker frames not included in the Max Delta calculation.

ui/tap-rtp-analysis.c:

    /* Is it a regular packet? */
    if (!(statinfo->flags & STAT_FLAG_FIRST)
            && !(statinfo->flags & STAT_FLAG_MARKER)
            && !(statinfo->flags & STAT_FLAG_PT_CN)
            && !(statinfo->flags & STAT_FLAG_WRONG_TIMESTAMP)
            && !(statinfo->flags & STAT_FLAG_FOLLOW_PT_CN)) {
        /* Include it in maximum delta calculation */
        if (statinfo->delta > statinfo->max_delta) {
            statinfo->max_delta = statinfo->delta;
            statinfo->max_nr = pinfo->num;
        }

Frame 18: 436 bytes on wire (3488 bits), 436 bytes captured (3488 bits)
Linux cooked capture v2
Internet Protocol Version 4, Src: 192.168.49.166 (192.168.49.166), Dst: 192.168.49.1 (192.168.49.1)
User Datagram Protocol, Src Port: 23704 (23704), Dst Port: 19900 (19900)
Real-Time Transport Protocol
    [Stream setup by HEUR RTP (frame 1)]
    10.. .... = Version: RFC 1889 Version (2)
    ..0. .... = Padding: False
    ...0 .... = Extension: False
    .... 0000 = Contributing source identifiers count: 0
    1... .... = Marker: True
    Payload type: MPEG-II transport streams (33)
    Sequence number: 17
    [Extended sequence number: 65553]
    Timestamp: 906791582
    [Extended timestamp: 5201758878]
    Synchronization Source identifier: 0xdeadbeef (3735928559)
<snip>