https://gitlab.gnome.org/GNOME/pitivi/-/commit/51ae6533ee26ffd47e453eb5f5ad8cd46f57d15e.patch (rebased)
https://bugs.gentoo.org/804945

--- a/meson.build
+++ b/meson.build
@@ -22,7 +22,6 @@ if get_option('build-gst')
         'gst-plugins-base:disable_gtkdoc=true',
         'gstreamer:disable_gtkdoc=true',
         ])
-    subproject('gst-transcoder')
 endif
 
 gst_dep = dependency('gstreamer-1.0', version : '>= 1.14.2',
@@ -30,9 +29,6 @@ gst_dep = dependency('gstreamer-1.0', version : '>= 1.14.2',
 cairo_dep = dependency('cairo')
 pycairo_dep = dependency('py3cairo')
 
-gst_transcoder_dep = dependency('gst-transcoder-1.0', version : '>= 1.8.1',
-    fallback : ['gst-transcoder', 'gst_transcoder_dep'])
-
 pkgdatadir = join_paths(get_option('datadir'), meson.project_name())
 
 git = find_program('git', required : false)
--- a/tests/__init__.py
+++ b/tests/__init__.py
@@ -59,12 +59,7 @@ def setup():
 
     # Make available the compiled C code.
     sys.path.append(configure.BUILDDIR)
-    subproject_paths = os.path.join(configure.BUILDDIR, "subprojects", "gst-transcoder")
-
-    _prepend_env_paths(LD_LIBRARY_PATH=subproject_paths,
-                       GST_PLUGIN_PATH=subproject_paths,
-                       GI_TYPELIB_PATH=subproject_paths,
-                       GST_PRESET_PATH=[os.path.join(pitivi_dir, "data", "videopresets"),
+    _prepend_env_paths(GST_PRESET_PATH=[os.path.join(pitivi_dir, "data", "videopresets"),
                                         os.path.join(pitivi_dir, "data", "audiopresets")],
                        GST_ENCODING_TARGET_PATH=[os.path.join(pitivi_dir, "tests", "test-encoding-targets"),
                                                  os.path.join(pitivi_dir, "data", "encoding-profiles")])