[vlc-devel] Branching?

jboileau jboileau at gmail.com
Thu Dec 20 16:53:28 CET 2007


Good news, last night's build doesn't crash anymore! I still have the video
freezing after a few seconds. I'll post traces, one with last nights build
and one with the 2007-11-26 build. Watch your mailboxes! :-) As a side note
we have a developer here that has installed gdb, cygwin and whatever else is
needed and is trying to compile VLC here. We should gain a better insight
into VLC and be able to report problems with more info in the future. He as
not succeeded at producing something that works yet, but in due time he
should be able to.

Since two of you asked: The project I work on is a media application
that display's movies and play's music through headphones on trains. Similar
to what you find on planes these days. The difficulty is that the audio
subsystem is not the same as the PC displaying the video of the movie. So I
am playing the video of the movie on a PC and streaming the audio to an
embedded system using UDP. I also stream 7 music playlist to the same
subsystem. I simply use different ports for each audio channel. The current
version of the application uses as many instances of vlc.exe (version 0.8.1)
as needed and controlling them using HTTP. Not the easiest route. :-) Now I
am working at doing the same thing but using libvlc. More details:

   - I use the libvlc_media_instance_...  API so that I can use the
   events API instead of polling a state. I used to use the libvlc_playlist_...
   API but couldn't find a way to get called backed on end of stream.
   - I use --sout-display-delay to synchronize the video with the audio
   for the movie. Unfortunately this has the effect of chopping the equivalent
   of the buffer from the end. I know this is a known bug and I have seen it is
   listed as high priority, but I will try to find a workaround. Maybe using
   one of the other buffering options.
   - I use GetProcAddress to get entry points into the DLL. Dangerous but
   since there is not libvlc-control.lib for Visual Studio, I believe its
   the only way.
   - The development is done for Windows using Visual Studio and MFC
   - I create a CWnd (MFC) and do a libvlc_video_set_parent to have
   libvlc play in my window.
   - This runs on a 650 Mhz Windows XP embedded machine with 256 meg of
   ram.

Jacques Boileau

On Dec 19, 2007 6:10 PM, Rafaël Carré <funman at videolan.org> wrote:

> Le Wed, 19 Dec 2007 17:53:07 -0500,
> jboileau <jboileau at gmail.com> a écrit :
>
> > On Dec 19, 2007 4:48 PM, Rafaël Carré <funman at videolan.org > wrote:
> >
> > > Le Wed, 19 Dec 2007 16:42:12 -0500,
> > > jboileau <jboileau at gmail.com> a écrit :
> > >
> > > > FYI - I have been doing quite a bit of testing under Windows
> > > > (mostly through libvlc-control) and the last nightly build that
> > > > worked well enough for me was the 2007-11-26 build which, if I am
> > > > correct, includes changeset 23325 and prior.
> > >
> > > What is the problem exactly, since these nightly build ?
> >
> >
> > The latest few builds simply crash. vlc.exe crashes on startup. My
> > application, built on libvlc, gets an access violation calling
> > libvlc_new. Older nightly builds after 2007-11-26, that do not crash,
> > do not play my divx files that played flawlessly using 2007-11-26
> > (except for the problem when using buffers of course. see here
> > https://trac.videolan.org/vlc/ticket/774). It would play well for
> > about 8 seconds and then freezes (the video not vlc).
>
> Ok, for crashes, without a verbose backtrace (including files and lines
> where the crash occurs) obtained with gdb (and i don't know how to use
> gdb on windows, you must ask our cygwin expert Trax) we can't do
> anything.
>


>
> > >
> > > > If I can be of help checking out releases under Windows let me
> > > > know. I'll be glad to help. I have been doing quick try out
> > > > almost daily recently trying to see if things are back to normal
> > > > under Windows, might as well continue! :-) The least I can do is
> > > > give you guys some feddback.
> > >
> > > Feedback is always welcome, (especially positive feedback).
> > > It can help also if you can make clear and reproducible bug reports
> > > on trac.videolan.org
> > >
> > I agree that positive feedback is one of the best reward for anyone
> > working on open source. As a positive note: I have been doing work
> > using VLC for about a 1 1/2 year now. I started using it as an
> > external application that I controlled using HTTP (version 0.8.1),
> > but now I am trying to move to using libvlc.dll directly in my
> > application. Although I use VLC in my work, I soon realized that this
> > seemingly small application (well, it is only about 2 cm high! :-) )
> > can play just about anything I throw at it without installing
> > anything else (codecs). Now it is my player of choice for personnal
> > use as well as what I use to develop a streaming application here at
> > work.
>
> Cool.
>
> > I will take a look at trac.videolan.org and see how I can help through
> > there. I have just recently found this mailing list through the
> > forum. I didn't get too many answers through the forum for the past 1
>
> A lot of people are asking questions on the forums, but a few are
> answering :/
> The preferred modes of communication are the mailing list and irc
> (#videolan on freenode).
>
> > 1/2 year until recently someone answered one of my request for help
> > by: try posting this on the dev mailing list! (Bless him!). I am new
> > to everything regarding development here and I have been reluctant to
> > jump too quickly on the bandwagon and simply filling reports of
> > already known problems, etc. I still kindy feel like I am intruding.
>
> Everyone is welcomed to speak since the lists are public !
> Feel free to express yourself, not having anyone answering can mean a
> lot of things (people don't read your mail, don't care, are too busy,
> forget about it .. etc ..)
>
> > But I had an excellent exchange of emails through this mailing list
> > with Pierre d'Herbermont which ended up with 2 additions that I am
> > sure will not be only worthwhile for me but to anyone using
> > libvlc.See https://trac.videolan.org/vlc/changeset/23618 and
> > https://trac.videolan.org/vlc/changeset/23606. He as been just great
> > helping out on these. I don't know where he is located (France?), but
> > to be able to get these fixes in a matter of minutes after discussing
> > with him on this list right from my kitchen table a very snowy
> > morning here in Montréal has been a gas!
>
> I think he's in Paris.
> Please send me some snow i'm missing it :(


> Just a note on would be OS bashes, if any. We can argue for hours how
> bad MS$ is but to me Windows and Visual Studio are what enables me to
> pay for my family`s needs. Sometimes choices are governed by real
> life necessities! :-) Unfortunatly libvlc is not the easiest to use
> in a Visual Studio environment, but I get by.

The problem is more that nobody fixes windows specific VLC bugs.
> I respect the choice people make about their OS as long as they don't
> bore me, even if they make a stupid choice ;)


> If you would like more details on the work I do with VLC, let me
> know...

What are you doing with VLC ? ;)




> > Jacques Boileau


--
Rafaël Carré

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-- 
Jacques Boileau
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