QtGstreamer and GstEncodeBin

[vaisaari]

Hi all,

I'm trying to learn QtGstreamer and use it with the GstEncodeBin. Unfortunately, I ran into the following problem: I'm guessing the GstEncodeBin is QGst::Bin, but what are the proper wrapper classes for GstEncodingContainerProfile and GstEncodingProfile? How do I create them in the QtGstreamer way?

Thank you for your help!
-V

[George Kiagiadakis]

On Mon, Feb 13, 2012 at 10:17 AM, vaisaari <[hidden email]> wrote:

> Hi all,
>
> I'm trying to learn QtGstreamer and use it with the GstEncodeBin.
> Unfortunately, I ran into the following problem: I'm guessing the
> GstEncodeBin is QGst::Bin, but what are the proper wrapper classes for
> GstEncodingContainerProfile and GstEncodingProfile? How do I create them in
> the QtGstreamer way?
>
> Thank you for your help!
> -V
>

Hi,

There are no bindings for these classes, therefore you can only create
them with the C API. You can of course, if you want, wrap them in
QGst::MiniObject class instances. This will probably be useful for
setting them as properties in the encodebin.

Regards,
George
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[vaisaari]

Thank you for your quick response! Unfortunately, this goes past my knowledge :(  How do I wrap them in QGst::MiniObject class instances?

Thanks,
-V

[George Kiagiadakis]

On Mon, Feb 13, 2012 at 2:44 PM, vaisaari <[hidden email]> wrote:
> Thank you for your quick response! Unfortunately, this goes past my knowledge
> :(  How do I wrap them in QGst::MiniObject class instances?
>
> Thanks,
> -V

GstEncodingProfile *profile = gst_whatever();
QGst::MiniObjectPtr profilePtr = QGst::MiniObjectPtr::wrap(profile);
gst_mini_object_unref(profile);
encodebin->setProperty("profile", profilePtr);
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[vaisaari]

My sincerest thanks to you George!
-V

[vaisaari]

I'm sorry to get back to this... I tried your suggestion, but the compiler returns following error:

error: no matching function for call to ‘QGlib::RefPointer<QGst::MiniObject>::wrap(GstEncodingProfile*&)’

candidate is:

/usr/include/QtGStreamer/QGst/../QGlib/refpointer.h:326: static QGlib::RefPointer<T> QGlib::RefPointer<T>::wrap(typename T::CType*, bool) [with T = QGst::MiniObject, typename T::CType = _GstMiniObject]

/usr/include/QtGStreamer/QGst/../QGlib/refpointer.h:326:   no known conversion for argument 1 from ‘GstEncodingProfile* {aka _GstEncodingProfile*}’ to ‘QGst::MiniObject::CType* {aka _GstMiniObject*}’


-V

[George Kiagiadakis]

On Wed, Feb 15, 2012 at 5:20 PM, vaisaari <[hidden email]> wrote:

> I'm sorry to get back to this... I tried your suggestion, but the compiler
> returns following error:
>
> error: no matching function for call to
> ‘QGlib::RefPointer<QGst::MiniObject>::wrap(GstEncodingProfile*&)’
>
> candidate is:
>
> /usr/include/QtGStreamer/QGst/../QGlib/refpointer.h:326: static
> QGlib::RefPointer<T> QGlib::RefPointer<T>::wrap(typename T::CType*, bool)
> [with T = QGst::MiniObject, typename T::CType = _GstMiniObject]
>
> /usr/include/QtGStreamer/QGst/../QGlib/refpointer.h:326:   no known
> conversion for argument 1 from ‘GstEncodingProfile* {aka
> _GstEncodingProfile*}’ to ‘QGst::MiniObject::CType* {aka _GstMiniObject*}’
>

Erm, right, I forgot you need to cast it:
QGst::MiniObjectPtr profilePtr =
QGst::MiniObjectPtr::wrap(GST_MINI_OBJECT(profile));
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[vaisaari]

Unfortunately, after casting "encodebin->setProperty("profile", profilePtr)" fails runtime:

"QGlib::Value::set: Unable to handle value type "GstMiniObject". This Value instance has been initialized to hold values of type "GstEncodingProfile" and no conversion is possible

CRITICAL **: gst_encode_bin_set_profile: assertion `GST_IS_ENCODING_PROFILE (profile)' failed"

-V

[George Kiagiadakis]

On Wed, Feb 15, 2012 at 5:41 PM, vaisaari <[hidden email]> wrote:

> Unfortunately, after casting "encodebin->setProperty("profile", profilePtr)"
> fails runtime:
>
> "QGlib::Value::set: Unable to handle value type "GstMiniObject". This Value
> instance has been initialized to hold values of type "GstEncodingProfile"
> and no conversion is possible
>
> CRITICAL **: gst_encode_bin_set_profile: assertion `GST_IS_ENCODING_PROFILE
> (profile)' failed"
>

Right, this is actually the expected behavior according to the code :S
I don't really remember why it behaves like that, I guess I should
change it to get the type of the object at runtime rather than at
compile time, so that it knows that your object is really a
GstEncodingProfile instead of just a GstMiniObject.

In the meantime, I guess you'll have to do it with the C api, i.e.
g_object_set()
Note that the smart pointers are implicitly convertable to their
equivalent C types, so you can use a QGlib::ObjectPtr instead of a
GObject* in g_object_set() directly.

Sorry for the confusion.

George
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[vaisaari]

No problem, I really appreciate your help. This actually solves my problem, I can use C api without throwing my QGst pipelines to trash. That's all I need.

-V