Hi,
Thanks for your help so far. I’ve made some progress but I’m still stuck.
I am still trying to create a ‘do nothing’ audiosink upon which I can build.
Is there a clear statement somewhere of what an C++ audiosink class must
provide?
I was able to create a a ‘do nothing’ sink using “gst-element-maker mydemosink
audiosink”
which seems to work but there is nothing obvious to translate from that code
into the C++ version.
The latest output is:
(gst-launch-1.0:16830): GStreamer-CRITICAL **: gst_object_set_parent: assertion
'GST_IS_OBJECT (object)' failed
** (gst-launch-1.0:16830): CRITICAL **: gst_audio_ring_buffer_open_device:
assertion 'GST_IS_AUDIO_RING_BUFFER (buf)' failed
(gst-launch-1.0:16830): GStreamer-CRITICAL **: gst_object_unparent: assertion
'GST_IS_OBJECT (object)' failed
ERROR: Pipeline doesn't want to pause.
I thought the ring buffer was provided by the parent class AudioBaseSink but
it seems not.
Note for testing this I’m using:
gst-launch-1.0 -v audiotestsrc blocksize=8000 num-buffers=10 !
audio/x-raw,rate=8000,channels=1 ! myaudiosink
The simplest MyAudioSink.hpp to reproduce this:
#include <gstreamermm.h>
#include <gstreamermm/audiosink.h>
class MyAudioSink: public Gst::AudioSink
{
public:
explicit MyAudioSink(Gst::AudioSink::BaseObjectType* gobj):
Glib::ObjectBase(typeid (MyAudioSink)), // type must be registered before
use
Gst::AudioSink(gobj)
{
}
virtual ~MyAudioSink()
{
}
static void class_init(Gst::ElementClass<MyAudioSink> *klass)
{
klass->set_metadata("MyAudioSink",
"Sink/Audio", "A test audio sink", "author");
klass->add_pad_template(Gst::PadTemplate::create("sink", Gst::PAD_SINK,
Gst::PAD_ALWAYS,
Gst::Caps::create_from_string("audio/x-raw,format=S16LE,rate=8000,channels=1")));
}
};
A C++ myaudiofilter derived from AudioFilter on the other hand seems to just
work:
gst-launch-1.0 audiotestsrc blocksize=8000 num-buffers=10 !
audio/x-raw,rate=8000,channels=1 ! myaudiofilter ! fakesink
Calling create_ring_buffer() in the constructor MyAudioSink causes a seg fault:
(gst-inspect-1.0:23564): GStreamer-CRITICAL **: gst_object_set_parent:
assertion 'GST_IS_OBJECT (object)' failed
(gst-inspect-1.0:23564): GLib-GObject-CRITICAL **: g_object_get_qdata:
assertion 'G_IS_OBJECT (object)' failed
(gst-inspect-1.0:23564): GLib-GObject-CRITICAL **: g_object_get_qdata:
assertion 'G_IS_OBJECT (object)' failed
Segmentation fault (core dumped)
#3 fault_handler_sighandler (signum=11) at gst-launch.c:94
#4 <signal handler called>
#5 0x00007eff8272b898 in Glib::wrap_auto(_GObject*, bool) () from
/usr/lib/x86_64-linux-gnu/libglibmm-2.4.so.1
#6 0x00007eff82df5bcf in Glib::wrap(_GstAudioRingBuffer*, bool) () from
/usr/lib/x86_64-linux-gnu/libgstreamermm-1.0.so.1
#7 0x00007eff82df16c6 in Gst::AudioBaseSink::create_ring_buffer() () from
/usr/lib/x86_64-linux-gnu/libgstreamermm-1.0.so.1
#8 0x00007eff830f5eb4 in MyAudioSink::MyAudioSink
I tried putting it in some of the vfunc’s like open, reset , write and start
instead but none of them are invoked before it starts asserting.
Its not immediately obvious where to set a breakpoint to try and track this down
I’m wading through glib and gstreamer source trying to find out without much
success so far.
Any tips would be appreciated.
Regards,
Bruce.
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