Wireshark-bugs: [Wireshark-bugs] [Bug 6996] Malformed Packets H263-1996 (RFC2190)

Date: Sun, 1 Apr 2012 02:25:03 -0700 (PDT)
https://bugs.wireshark.org/bugzilla/show_bug.cgi?id=6996

Anders Broman <anders.broman@xxxxxxxxxxxx> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |FIXED

--- Comment #1 from Anders Broman <anders.broman@xxxxxxxxxxxx> 2012-04-01 02:25:02 PDT ---
A fix committed revision 41876. I'll mark this for backporting to 1.6.x
The H263 dissector needed at least 4 bytes to look for a PSC.

As for the validity of the stream

-- RFC 2190 --
5.1 Mode A

   In this mode, an H.263 bitstream will be packetized on a GOB boundary
   or a picture boundary. Mode A packets always start with the H.263
   picture start code [4] or a GOB, but do not necessarily contain
   complete GOBs. Four bytes are used for the mode A H.263 payload
   header. The H.263 payload header definition for mode A is shown as
   follows with F=0. Mode A packets are allowed to start at a GOB
   boundary even if no GOB header is present in the bitstream for the
   GOB.  However, such use is discouraged due to the dependencies it
                  ^^^^^^^^^^^^^^^^^^^^^^^
   creates across GOB boundaries, as described in Section 3.3.
--- RFC 2190 ---

One would expect a GOB header at the start of the data and sending so
few bytes in an RTP packet seem very inefficient.

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