Refactor (See desc)

* Create `FFmpegPostProcessor.real_run_ffmpeg` that can accept multiple input/output files along with switches for each
* Rewrite `cli_configuration_args` and related functions
* Create `YoutubeDL._ensure_dir_exists` - this was previously defined in multiple places

yt_dlp/postprocessor/common.py

@@ -91,10 +91,18 @@ class PostProcessor(object):
         except Exception:
             self.report_warning(errnote)
 
-    def _configuration_args(self, *args, **kwargs):
+    def _configuration_args(self, exe, keys=None, default=[], use_compat=True):
+        pp_key = self.pp_key().lower()
+        exe = exe.lower()
+        root_key = exe if pp_key == exe else '%s+%s' % (pp_key, exe)
+        keys = ['%s%s' % (root_key, k) for k in (keys or [''])]
+        if root_key in keys:
+            keys += [root_key] + ([] if pp_key == exe else [(self.pp_key(), exe)]) + ['default']
+        else:
+            use_compat = False
         return cli_configuration_args(
             self._downloader.params.get('postprocessor_args'),
-            self.pp_key().lower(), *args, **kwargs)
+            keys, default, use_compat)
 
 
 class AudioConversionError(PostProcessingError):

yt_dlp/postprocessor/embedthumbnail.py

@@ -139,7 +139,7 @@ class EmbedThumbnailPP(FFmpegPostProcessor):
                        encodeFilename(thumbnail_filename, True),
                        encodeArgument('-o'),
                        encodeFilename(temp_filename, True)]
-                cmd += [encodeArgument(o) for o in self._configuration_args(exe='AtomicParsley')]
+                cmd += [encodeArgument(o) for o in self._configuration_args('AtomicParsley')]
 
                 self.to_screen('Adding thumbnail to "%s"' % filename)
                 self.write_debug('AtomicParsley command line: %s' % shell_quote(cmd))

yt_dlp/postprocessor/ffmpeg.py

@@ -234,25 +234,35 @@ class FFmpegPostProcessor(PostProcessor):
         return num, len(streams)
 
     def run_ffmpeg_multiple_files(self, input_paths, out_path, opts):
+        return self.real_run_ffmpeg(
+            [(path, []) for path in input_paths],
+            [(out_path, opts)])
+
+    def real_run_ffmpeg(self, input_path_opts, output_path_opts):
         self.check_version()
 
         oldest_mtime = min(
-            os.stat(encodeFilename(path)).st_mtime for path in input_paths)
+            os.stat(encodeFilename(path)).st_mtime for path, _ in input_path_opts)
 
         cmd = [encodeFilename(self.executable, True), encodeArgument('-y')]
         # avconv does not have repeat option
         if self.basename == 'ffmpeg':
             cmd += [encodeArgument('-loglevel'), encodeArgument('repeat+info')]
 
-        def make_args(file, pre=[], post=[], *args, **kwargs):
-            args = pre + self._configuration_args(*args, **kwargs) + post
+        def make_args(file, args, name, number):
+            keys = ['_%s%d' % (name, number), '_%s' % name]
+            if name == 'o' and number == 1:
+                keys.append('')
+            args += self._configuration_args(self.basename, keys)
+            if name == 'i':
+                args.append('-i')
             return (
-                [encodeArgument(o) for o in args]
+                [encodeArgument(arg) for arg in args]
                 + [encodeFilename(self._ffmpeg_filename_argument(file), True)])
 
-        for i, path in enumerate(input_paths):
-            cmd += make_args(path, post=['-i'], exe='%s_i%d' % (self.basename, i + 1), use_default_arg=False)
-        cmd += make_args(out_path, pre=opts, exe=self.basename)
+        for arg_type, path_opts in (('i', input_path_opts), ('o', output_path_opts)):
+            cmd += [arg for i, o in enumerate(path_opts)
+                    for arg in make_args(o[0], o[1], arg_type, i + 1)]
 
         self.write_debug('ffmpeg command line: %s' % shell_quote(cmd))
         p = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE, stdin=subprocess.PIPE)
@@ -262,7 +272,8 @@ class FFmpegPostProcessor(PostProcessor):
             if self.get_param('verbose', False):
                 self.report_error(stderr)
             raise FFmpegPostProcessorError(stderr.split('\n')[-1])
-        self.try_utime(out_path, oldest_mtime, oldest_mtime)
+        for out_path, _ in output_path_opts:
+            self.try_utime(out_path, oldest_mtime, oldest_mtime)
         return stderr.decode('utf-8', 'replace')
 
     def run_ffmpeg(self, path, out_path, opts):

yt_dlp/postprocessor/sponskrub.py

@@ -71,7 +71,7 @@ class SponSkrubPP(PostProcessor):
         if not self.cutout:
             cmd += ['-chapter']
         cmd += compat_shlex_split(self.args)  # For backward compatibility
-        cmd += self._configuration_args(exe=self._exe_name, use_default_arg='no_compat')
+        cmd += self._configuration_args(self._exe_name, use_compat=False)
         cmd += ['--', information['id'], filename, temp_filename]
         cmd = [encodeArgument(i) for i in cmd]