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Wireshark-users: Re: [Wireshark-users] MPEG2TS over UPD not decoded

From: Graham Bloice <graham.bloice@xxxxxxxxxxxxx>
Date: Wed, 09 Jan 2008 10:27:41 +0000
Guy Harris wrote:
> Kaliwoda, Arkadiusz wrote:
>   
>> Hi,
>>
>>  
>>
>> I have downloaded the latest revision of WireShark 23910; according to 
>> information I found in the history I believe that decoding MPEG2TS over 
>> UDP should work “out-of-the-box”:
>>
>> /Hi,/
>>
>> / /
>>
>> /Committed revision 23743 adding UDP transport for MPEG2TS, both 
>> heuristic and "Decode as". ///
>>
>> / /
>>
>> /Thanx,/
>>
>> /Jaap/
>>
>>  
>>
>> On the latest 0.99.7 23910 it doesn’t work in heuristic mode and I 
>> cannot also find it in “Decode As…”
>>     
>
> SVN revision numbers can be confusing.  Each change to the code 
> repository has a revision number assigned to it when the checkin for 
> that change happens.  If two given changes to the code repository have 
> numbers N and M, respectively, and N > M, all you can deduce from that 
> is that the checkin for N was done after the checkin for M.
>
> See
>
> 	http://subversion.tigris.org/faq.html#changesets
>
> A branch, in Subversion, is a copy of everything in the code base. 
> (It's implemented, as I understand it, with copy-on-write, so it doesn't 
> make a physical copy of the files.)  The copy is part of the same 
> repository as the main line ("trunk"), so, for example, if you check a 
> change into the trunk at one point and into a branch after that, the SVN 
> revision number for the change on the branch will be greater than the 
> SVN revision number for the change on the trunk, *even if the branch was 
> created before either of the two changes*.
>
> A branch is part of the *same* code repository as the trunk, so there's 
> a single sequence of SVN revision numbers for changes to the trunk and 
> all branches:
>
> 	http://subversion.tigris.org/faq.html#globalrev
>
> This means that a branch is a change to the repository, as it adds a 
> subtree that's a copy of the subtree from which you branched.  The 
> branch itself thus gets an SVN revision number.
>
> This all means that, for example, if you:
>
> 	branch off a "wireshark-0.9.7" branch;
>
> 	check a change into the trunk;
>
> 	check another change into the trunk;
>
> 	propagate the first of those two changes to the "wireshark-0.9.7" branch;
>
> then the top of the "wireshark-0.9.7" branch will have a higher SVN 
> revision number than the top of the trunk does, *even though the trunk 
> has changes in it that the branch doesn't*.
>
> See
>
> 	http://svnbook.red-bean.com/en/1.4/svn-book.html
>
> for the full gory details.
>
> The branch that created the "trunk-0.99.7" branch had an SVN revision 
> number of 23524:
>
> 	http://anonsvn.wireshark.org/viewvc/viewvc.py/trunk-0.99.7/epan/dissectors/packet-mp2t.c?view=log&pathrev=23524
>
> The only other change to the MPEG2TS dissector for 0.99.7 was an 
> ex-post-facto copy of the "trunk-0.99.7" branch to 
> "releases/wireshark-0.99.7":
> 	http://anonsvn.wireshark.org/viewvc/viewvc.py/releases/wireshark-0.99.7/epan/dissectors/packet-mp2t.c?view=log
>
> The change that added support for MPEG2TS-over-UDP was checked into the 
> trunk with an SVN revision number of 23743:
>
> 	http://anonsvn.wireshark.org/viewvc/viewvc.py/trunk/epan/dissectors/packet-mp2t.c?view=log
>
> which happened *after* the "trunk-0.99.7" branch was created, and that 
> change was not propagated to that branch, so it's not on that branch.
>
>   
So to get acces to this change, either build it yourself from the svn
trunk using either the HEAD or at least a revision greater than 23743,
or pickup an automated build or tarball from
http://www.wireshark.org/download/automated with a rev number greater
than 23743.  Note in both these cases you'll be using a development
version of Wireshark so things may occasionally be broken.

-- 
Regards,

Graham Bloice