Re: [Vala] Problem with gstreamer bin

["Spencer, Matthew" <MSpencer nds com>]

Sure, that will work.  But most people who use GStreamer are used to the
convenience function add_many and will want to be able to use this when
using Vala.

Matt 

-----Original Message-----
From: Thijs Vermeir [mailto:thijsvermeir gmail com] 
Sent: 14 November 2008 17:29
To: Spencer, Matthew
Cc: vala-list gnome org
Subject: Re: [Vala] Problem with gstreamer bin

On Fri, Nov 14, 2008 at 6:22 PM, Spencer, Matthew <MSpencer nds com>
wrote:
> The problem I have with that approach however is that the elements 
> will be set to NULL after passing ownership to the bin, so I can no 
> longer use them in the functions.  What I need is the ability to pass 
> ownership and change them into weak references for the rest of the
function scope.
> I don't suppose there is any way of achieving this is there?

With bin.add you take a ref of the element so you can keep them using in
your function.

Gr,
Thijs


> Matt
>
> -----Original Message-----
> From: Thijs Vermeir [mailto:thijsvermeir gmail com]
> Sent: 14 November 2008 17:15
> To: Spencer, Matthew
> Cc: vala-list gnome org
> Subject: Re: [Vala] Problem with gstreamer bin
>
> On Fri, Nov 14, 2008 at 6:12 PM, Spencer, Matthew <MSpencer nds com>
> wrote:
> > I thought it was something like this.  Thanks for the feedback, this 
> > has fixed the problem.
> >
> > Reading through the documents, shouldn't I be able to do something
> like:
> >  bin.add_many(#element1,#element2,#elemenr3)
> >
> > To indicate to valac the passing of ownership to the bin?
>
> Yes, that should also work.
>
> Gr,
> Thijs
>
> > Matt
> >
> > -----Original Message-----
> > From: Thijs Vermeir [mailto:thijsvermeir gmail com]
> > Sent: 14 November 2008 17:07
> > To: Spencer, Matthew
> > Cc: vala-list gnome org
> > Subject: Re: [Vala] Problem with gstreamer bin
> >
> > Hi,
> >
> > 2008/11/14 Spencer, Matthew <MSpencer nds com>:
> > > Hi Guys
> > >
> > > I am playing with Vala with a view to presenting information about 
> > > it
>
> > > at our companies developer conference in a couple of weeks.  With 
> > > this
> >
> > > in mind I am trying to build up a test application that shows video 
> > > playback using GStreamer.  I am having problems with the following
> > code:
> > > private Element createVideoBin() {
> > >   var bin=new Bin("videobin");
> > >   var queue=ElementFactory.make("queue","queue");
> > >   var sink=ElementFactory.make("autovideosink","videosink");
> > >   var ghostPad=new GhostPad("sink",queue.get_pad("sink"));
> > >   bin.add_many(queue,sink);
> > >   queue.link(sink);
> > >   bin.add_pad(ghost);
> > >   return(bin);
> > > }
> >
> > bin.add_many is the problem because the c function takes the 
> > ownership, but the bindings don't do it. Just use bin.add for every 
> > element as a workaround...
> >
> > Gr,
> > Thijs
> >
> > > When attempting to use the returned bin, I get a segfault.  This is 
> > > because (I think, on examining the generated C code) the elements 
> > > are
>
> > > being unrefd before the bin is returned.  I am sure this is not
> > supposed to happen.
> > > I get a number of error messaged when running the app:
> > > (mystreamer:16361): GStreamer-CRITICAL **:
> > > Trying to dispose of object "videosink", but it still has a parent 
> > > "videobin".
> > > You need to let the parent manage the object instead of unreffing 
> > > the
>
> > > object directly.
> > >
> > > I am assuming this is because I need to inform the code that I wish 
> > > to
> >
> > > transfer ownership of the objects to the 'Bin', but how do I do 
> > > this,
>
> > > and is there a way that this can be picked up by the compiler to 
> > > prevent this type of problem?
> > >
> > > Cheers
> > >
> > > Matt
> > > ********************************************************************
> > > *
> > > *
> > > ***********************************
> > > This e-mail is confidential, the property of NDS Ltd and intended 
> > > for
>
> > > the addressee only. Any dissemination, copying or distribution of 
> > > this
> >
> > > message or any attachments by anyone other than the intended 
> > > recipient
> >
> > > is strictly prohibited. If you have received this message in error, 
> > > please immediately notify the postmaster nds com and destroy the 
> > > original message. Messages sent to and from NDS may be monitored. 
> > > NDS
>
> > > cannot guarantee any message delivery method is secure or
error-free.
> > > Information could be intercepted, corrupted, lost, destroyed, arrive
> > late or incomplete, or contain viruses.
> > > We do not accept responsibility for any errors or omissions in this 
> > > message and/or attachment that arise as a result of transmission. 
> > > You
>
> > > should carry out your own virus checks before opening any
attachment.
> > > Any views or opinions presented are solely those of the author and 
> > > do
>
> > > not necessarily represent those of NDS.
> > >
> > > To protect the environment please do not print this e-mail unless
> > necessary.
> > > NDS Limited Registered office: One Heathrow Boulevard, 286 Bath 
> > > Road,
>
> > > West Drayton, Middlesex, UB7 0DQ, United Kingdom. A company 
> > > registered
> >
> > > in England and Wales Registered no. 3080780 VAT no. GB 603 8808 
> > > 40-00
> > > ********************************************************************
> > > *
> > > *
> > > ************************************
> > >
> > > _______________________________________________
> > > Vala-list mailing list
> > > Vala-list gnome org
> > > http://mail.gnome.org/mailman/listinfo/vala-list
> >
> > *********************************************************************
> > *
> > ***********************************
> > This e-mail is confidential, the property of NDS Ltd and intended for
> the addressee only.  Any dissemination, copying or distribution of 
> this message or any attachments by anyone other than the intended 
> recipient is strictly prohibited.  If you have received this message 
> in error, please immediately notify the postmaster nds com and destroy

> the original message.  Messages sent to and from NDS may be monitored.

> NDS cannot guarantee any message delivery method is secure or
error-free.
> Information could be intercepted, corrupted, lost, destroyed, arrive 
> late or incomplete, or contain viruses.  We do not accept 
> responsibility for any errors or omissions in this message and/or 
> attachment that arise as a result of transmission.  You should carry 
> out your own virus checks before opening any attachment.  Any views or

> opinions presented are solely those of the author and do not 
> necessarily represent those of NDS.
> > To protect the environment please do not print this e-mail unless
> necessary.
> > NDS Limited Registered office: One Heathrow Boulevard, 286 Bath Road,
> West Drayton, Middlesex, UB7 0DQ, United Kingdom. A company registered
> in England and Wales  Registered no. 3080780   VAT no. GB 603 8808
40-00
> > *********************************************************************
> > *
> > ************************************
>
> **********************************************************************
> ***********************************
> This e-mail is confidential, the property of NDS Ltd and intended for
the addressee only.  Any dissemination, copying or distribution of this
message or any attachments by anyone other than the intended recipient
is strictly prohibited.  If you have received this message in error,
please immediately notify the postmaster nds com and destroy the
original message.  Messages sent to and from NDS may be monitored.  NDS
cannot guarantee any message delivery method is secure or error-free.
Information could be intercepted, corrupted, lost, destroyed, arrive
late or incomplete, or contain viruses.  We do not accept responsibility
for any errors or omissions in this message and/or attachment that arise
as a result of transmission.  You should carry out your own virus checks
before opening any attachment.  Any views or opinions presented are
solely those of the author and do not necessarily represent those of
NDS.
> To protect the environment please do not print this e-mail unless
necessary.
> NDS Limited Registered office: One Heathrow Boulevard, 286 Bath Road,
West Drayton, Middlesex, UB7 0DQ, United Kingdom. A company registered
in England and Wales  Registered no. 3080780   VAT no. GB 603 8808 40-00
> **********************************************************************
> ************************************

*********************************************************************************************************
This e-mail is confidential, the property of NDS Ltd and intended for the addressee only.  Any dissemination, 
copying or distribution of this message or any attachments by anyone other than the intended recipient is 
strictly prohibited.  If you have received this message in error, please immediately notify the postmaster 
nds com and destroy the original message.  Messages sent to and from NDS may be monitored.  NDS cannot 
guarantee any message delivery method is secure or error-free.  Information could be intercepted, corrupted, 
lost, destroyed, arrive late or incomplete, or contain viruses.  We do not accept responsibility for any 
errors or omissions in this message and/or attachment that arise as a result of transmission.  You should 
carry out your own virus checks before opening any attachment.  Any views or opinions presented are solely 
those of the author and do not necessarily represent those of NDS.

To protect the environment please do not print this e-mail unless necessary.

NDS Limited Registered office: One Heathrow Boulevard, 286 Bath Road, West Drayton, Middlesex, UB7 0DQ, 
United Kingdom. A company registered in England and Wales  Registered no. 3080780   VAT no. GB 603 8808 40-00
**********************************************************************************************************