[pitivi] proxy: Port to the new GstTranscoder api

[Alexandru Băluț <alexbalut src gnome org>]

commit a85c9dfc80704346b2bba73b5c4902b792fe92e4
Author: Thibault Saunier <tsaunier igalia com>
Date:   Fri Feb 26 18:04:01 2021 -0300

    proxy: Port to the new GstTranscoder api
    
    See https://gitlab.freedesktop.org/gstreamer/gst-plugins-bad/-/merge_requests/1840

 pitivi/check.py       | 10 +++++++---
 pitivi/utils/proxy.py | 40 +++++++++++++++++++++++-----------------
 2 files changed, 30 insertions(+), 20 deletions(-)
---
diff --git a/pitivi/check.py b/pitivi/check.py
index 8fe870bc9..9c429b26d 100644
--- a/pitivi/check.py
+++ b/pitivi/check.py
@@ -60,6 +60,9 @@ class Dependency:
         """Checks whether the dependency is satisfied.
 
         Sets the `satisfied` field to True or False.
+
+        Returns:
+            True if the requirement is satisfied, False otherwise
         """
         self.component = self._try_importing_component()
 
@@ -75,6 +78,8 @@ class Dependency:
                 if formatted_version >= _string_to_list(self.version_required):
                     self.satisfied = True
 
+        return self.satisfied
+
     def _try_importing_component(self):
         """Performs the check.
 
@@ -301,8 +306,7 @@ def check_requirements():
         print(dependency)
 
     for dependency in SOFT_DEPENDENCIES:
-        dependency.check()
-        if not dependency.satisfied:
+        if not dependency.check():
             MISSING_SOFT_DEPS[dependency.modulename] = dependency
             print(_("Missing soft dependency:"))
             print(dependency)
@@ -422,7 +426,7 @@ def initialize_modules():
 # a specific version requirement, they have the "None" value.
 
 GST_API_VERSION = "1.0"
-GST_VERSION = "1.17.90"
+GST_VERSION = "1.17.90"  # FIXME Remove check in proxy.py once we bump to > 1.19
 GTK_API_VERSION = "3.0"
 GLIB_API_VERSION = "2.0"
 HARD_DEPENDENCIES = [GICheck(version_required="3.20.0"),
diff --git a/pitivi/utils/proxy.py b/pitivi/utils/proxy.py
index 76e77d791..b33dd3add 100644
--- a/pitivi/utils/proxy.py
+++ b/pitivi/utils/proxy.py
@@ -27,12 +27,15 @@ from gi.repository import Gst
 from gi.repository import GstPbutils
 from gi.repository import GstTranscoder
 
+from pitivi.check import GstDependency
 from pitivi.configure import get_gstpresets_dir
 from pitivi.dialogs.prefs import PreferencesDialog
 from pitivi.settings import GlobalSettings
 from pitivi.utils.loggable import Loggable
 from pitivi.utils.misc import ASSET_DURATION_META
 from pitivi.utils.misc import asset_get_duration
+# Remove check when we depend on Gst >= 1.20
+HAS_GST_1_19 = GstDependency("Gst", apiversion="1.0", version_required="1.19").check()
 
 # Make sure gst knowns about our own GstPresets
 Gst.preset_set_app_dir(get_gstpresets_dir())
@@ -503,13 +506,13 @@ class ProxyManager(GObject.Object, Loggable):
             self.emit("proxy-ready", asset, proxy)
             self.__emit_progress(proxy, 100)
 
-    def __transcoder_error_cb(self, transcoder, error, unused_details, asset):
+    def __transcoder_error_cb(self, _, error, unused_details, asset, transcoder):
         self.emit("error-preparing-asset", asset, None, error)
 
-    def __transcoder_done_cb(self, transcoder, asset):
-        transcoder.disconnect_by_func(self.__proxying_position_changed_cb)
-        transcoder.disconnect_by_func(self.__transcoder_done_cb)
-        transcoder.disconnect_by_func(self.__transcoder_error_cb)
+    def __transcoder_done_cb(self, emitter, asset, transcoder):
+        emitter.disconnect_by_func(self.__proxying_position_changed_cb)
+        emitter.disconnect_by_func(self.__transcoder_done_cb)
+        emitter.disconnect_by_func(self.__transcoder_error_cb)
 
         self.debug("Transcoder done with %s", asset.get_id())
 
@@ -566,7 +569,7 @@ class ProxyManager(GObject.Object, Loggable):
         asset.creation_progress = creation_progress
         self.emit("progress", asset, asset.creation_progress, estimated_time)
 
-    def __proxying_position_changed_cb(self, transcoder, position, asset):
+    def __proxying_position_changed_cb(self, _, position, asset, transcoder):
         if transcoder not in self.__running_transcoders:
             self.info("Position changed after job cancelled!")
             return
@@ -663,15 +666,18 @@ class ProxyManager(GObject.Object, Loggable):
                 project.scaled_proxy_width = w
                 project.scaled_proxy_height = h
             width, height = self._scale_asset_resolution(asset, w, h)
-
-        dispatcher = GstTranscoder.TranscoderGMainContextSignalDispatcher.new()
-
         enc_profile = self.__get_encoding_profile(self.__encoding_target_file,
                                                   asset, width, height)
 
-        transcoder = GstTranscoder.Transcoder.new_full(
-            asset_uri, proxy_uri + ProxyManager.part_suffix, enc_profile,
-            dispatcher)
+        if HAS_GST_1_19:
+            transcoder = GstTranscoder.Transcoder.new_full(
+                asset_uri, proxy_uri + ProxyManager.part_suffix, enc_profile)
+            signals_emitter = transcoder.get_signal_adapter(None)
+        else:
+            dispatcher = GstTranscoder.TranscoderGMainContextSignalDispatcher.new()
+            signals_emitter = transcoder = GstTranscoder.Transcoder.new_full(
+                asset_uri, proxy_uri + ProxyManager.part_suffix, enc_profile,
+                dispatcher)
 
         if shadow:
             # Used to identify shadow transcoder
@@ -692,12 +698,12 @@ class ProxyManager(GObject.Object, Loggable):
             transcoder.props.pipeline.props.audio_filter = waveformbin
 
         transcoder.set_cpu_usage(self.app.settings.max_cpu_usage)
-        transcoder.connect("position-updated",
-                           self.__proxying_position_changed_cb,
-                           asset)
+        signals_emitter.connect("position-updated",
+                                self.__proxying_position_changed_cb,
+                                asset, transcoder)
 
-        transcoder.connect("done", self.__transcoder_done_cb, asset)
-        transcoder.connect("error", self.__transcoder_error_cb, asset)
+        signals_emitter.connect("done", self.__transcoder_done_cb, asset, transcoder)
+        signals_emitter.connect("error", self.__transcoder_error_cb, asset, transcoder)
 
         if len(self.__running_transcoders) < self.app.settings.num_transcoding_jobs:
             self.__start_transcoder(transcoder)