Let play webcam from PipeWire

cobang/app.py

@@ -121,10 +121,10 @@ def setup_actions(self):
         action_about.connect('activate', self.show_about_dialog)
         self.add_action(action_about)
 
-    def build_gstreamer_pipeline(self):
+    def build_gstreamer_pipeline(self, src_type: str = 'v4l2src'):
         # https://gstreamer.freedesktop.org/documentation/application-development/advanced/pipeline-manipulation.html?gi-language=c#grabbing-data-with-appsink
         # Try GL backend first
-        command = (f'v4l2src name={self.GST_SOURCE_NAME} ! tee name=t ! '
+        command = (f'{src_type} name={self.GST_SOURCE_NAME} ! tee name=t ! '
                    f'queue ! glsinkbin sink="gtkglsink name={self.SINK_NAME}" name=sink_bin '
                    't. ! queue leaky=2 max-size-buffers=2 ! videoconvert ! video/x-raw,format=GRAY8 ! '
                    f'appsink name={self.APPSINK_NAME} max_buffers=2 drop=1')
@@ -137,7 +137,7 @@ def build_gstreamer_pipeline(self):
         if not pipeline:
             logger.info('OpenGL is not available, fallback to normal GtkSink')
             # Fallback to non-GL
-            command = (f'v4l2src name={self.GST_SOURCE_NAME} ! videoconvert ! tee name=t ! '
+            command = (f'{src_type} name={self.GST_SOURCE_NAME} ! videoconvert ! tee name=t ! '
                        f'queue ! gtksink name={self.SINK_NAME} '
                        't. ! queue leaky=1 max-size-buffers=2 ! video/x-raw,format=GRAY8 ! '
                        f'appsink name={self.APPSINK_NAME}')
@@ -216,8 +216,11 @@ def discover_webcam(self):
             # Device is of private type GstV4l2Device or GstPipeWireDevice
             logger.debug('Found device {}', d.get_path_string())
             cam_name = d.get_display_name()
-            cam_path = get_device_path(d)
-            self.webcam_store.append((cam_path, cam_name))
+            cam_path, src_type = get_device_path(d)
+            if not cam_name:
+                logger.error('Not recognize this device.')
+                continue
+            self.webcam_store.append((cam_path, cam_name, src_type))
         logger.debug('Start device monitoring')
         self.devmonitor.start()
 
@@ -255,6 +258,16 @@ def replace_webcam_placeholder_with_gstreamer_sink(self):
         self.cont_webcam.add(area)
         area.show()
 
+    def detach_gstreamer_sink_from_window(self):
+        old_area = self.cont_webcam.get_child()
+        self.cont_webcam.remove(old_area)
+
+    def attach_gstreamer_sink_to_window(self):
+        sink = self.gst_pipeline.get_by_name(self.SINK_NAME)
+        area = sink.get_property('widget')
+        self.cont_webcam.add(area)
+        area.show()
+
     def grab_focus_on_event_box(self):
         event_box: Gtk.EventBox = self.frame_image.get_child()
         event_box.grab_focus()
@@ -354,23 +367,23 @@ def on_device_monitor_message(self, bus: Gst.Bus, message: Gst.Message, user_dat
             if not added_dev:
                 return True
             logger.debug('Added: {}', added_dev)
-            cam_path = get_device_path(added_dev)
+            cam_path, src_type = get_device_path(added_dev)
             cam_name = added_dev.get_display_name()
             # Check if this cam already in the list, add to list if not.
             for row in self.webcam_store:
                 if row[0] == cam_path:
                     break
             else:
-                self.webcam_store.append((cam_path, cam_name))
+                self.webcam_store.append((cam_path, cam_name, src_type))
             return True
         elif message.type == Gst.MessageType.DEVICE_REMOVED:
             removed_dev: Optional[Gst.Device] = message.parse_device_removed()
             if not removed_dev:
                 return True
             logger.debug('Removed: {}', removed_dev)
-            cam_path = get_device_path(removed_dev)
+            cam_path, src_type = get_device_path(removed_dev)
             ppl_source = self.gst_pipeline.get_by_name(self.GST_SOURCE_NAME)
-            if cam_path == ppl_source.get_property('device'):
+            if cam_path == ppl_source.get_property('device') or cam_path == ppl_source.get_property('path'):
                 self.gst_pipeline.set_state(Gst.State.NULL)
             # Find the entry of just-removed in the list and remove it.
             itr: Optional[Gtk.TreeIter] = None
@@ -391,11 +404,24 @@ def on_webcam_combobox_changed(self, combo: Gtk.ComboBox):
         if not liter:
             return
         model = combo.get_model()
-        path, name = model[liter]
-        logger.debug('Picked {} {}', path, name)
+        path, name, source_type = model[liter]
+        logger.debug('Picked {} {} ({})', path, name, source_type)
+        app_sink = self.gst_pipeline.get_by_name(self.APPSINK_NAME)
+        app_sink.set_emit_signals(False)
+        self.detach_gstreamer_sink_from_window()
+        self.gst_pipeline.remove(app_sink)
         ppl_source = self.gst_pipeline.get_by_name(self.GST_SOURCE_NAME)
-        self.gst_pipeline.set_state(Gst.State.NULL)
-        ppl_source.set_property('device', path)
+        ppl_source.set_state(Gst.State.NULL)
+        self.gst_pipeline.remove(ppl_source)
+        self.build_gstreamer_pipeline(source_type)
+        self.attach_gstreamer_sink_to_window()
+        ppl_source = self.gst_pipeline.get_by_name(self.GST_SOURCE_NAME)
+        if source_type == 'pipewiresrc':
+            logger.debug('Change pipewiresrc path to {}', path)
+            ppl_source.set_property('path', path)
+        else:
+            logger.debug('Change v4l2src device to {}', path)
+            ppl_source.set_property('device', path)
         self.gst_pipeline.set_state(Gst.State.PLAYING)
         app_sink = self.gst_pipeline.get_by_name(self.APPSINK_NAME)
         app_sink.set_emit_signals(True)

cobang/prep.py

@@ -1,8 +1,9 @@
 import io
 from fractions import Fraction
-from typing import Sequence, Optional
+from typing import Sequence, Optional, Tuple
 
 import gi
+from logbook import Logger
 
 gi.require_version('Gio', '2.0')
 gi.require_version('GdkPixbuf', '2.0')
@@ -13,6 +14,9 @@
 from .resources import is_local_real_image, maybe_remote_image
 
 
+logger = Logger(__name__)
+
+
 def choose_first_image(uris: Sequence[str]) -> Optional[Gio.File]:
     for u in uris:
         gfile: Gio.File = Gio.file_new_for_uri(u)
@@ -26,15 +30,18 @@ def choose_first_image(uris: Sequence[str]) -> Optional[Gio.File]:
             return gfile
 
 
-def get_device_path(device: Gst.Device):
+def get_device_path(device: Gst.Device) -> Tuple[str, str]:
     type_name = device.__class__.__name__
     # GstPipeWireDevice doesn't have dedicated GIR binding yet,
     # so we have to access its "device.path" in general GStreamer way
     if type_name == 'GstPipeWireDevice':
         properties = device.get_properties()
-        return properties['device.path']
+        path = properties['device.path']
+        if not path:
+            path = properties['api.v4l2.path']
+        return path, 'pipewiresrc'
     # Assume GstV4l2Device
-    return device.get_property('device_path')
+    return device.get_property('device_path'), 'v4l2src'
 
 
 def scale_pixbuf(pixbuf: GdkPixbuf.Pixbuf, outer_width: int, outer_height):

data/main.glade

@@ -120,6 +120,8 @@
       <column type="gchararray"/>
       <!-- column-name name -->
       <column type="gchararray"/>
+      <!-- column-name source_type -->
+      <column type="gchararray"/>
     </columns>
   </object>
   <object class="GtkApplicationWindow" id="main-window">

data/vn.hoabinh.quan.CoBang.appdata.xml

@@ -40,6 +40,11 @@
   </kudos>
 
   <releases>
+    <release version="0.8.0" date="2021-03-07" urgency="medium">
+      <description>
+        <p>Let play webcam from PipeWire.</p>
+      </description>
+    </release>
     <release version="0.7.0" date="2021-03-06" urgency="medium">
       <description>
         <p>Add button to copy raw result.</p>

meson.build

@@ -1,5 +1,5 @@
 project('cobang',
-        version: '0.7.0',
+        version: '0.8.0',
         meson_version: '>= 0.54',
         default_options: [
           'warning_level=2',

pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "cobang"
-version = "0.7.0"
+version = "0.8.0"
 description = "QR code scanner for Linux desktop"
 authors = ["Nguyễn Hồng Quân <[email protected]>"]
 license = "GPL-3.0-or-later"