[ffmpeg] Allow passing custom arguments before -i

:ci skip dl

youtube_dlc/postprocessor/common.py

@@ -91,11 +91,10 @@ class PostProcessor(object):
         except Exception:
             self.report_warning(errnote)
 
-    def _configuration_args(self, default=[], exe=None):
-        key = self.pp_key().lower()
-        args, is_compat = cli_configuration_args(
-            self._downloader.params, 'postprocessor_args', key, default, exe)
-        return args if not is_compat or key != 'sponskrub' else default
+    def _configuration_args(self, *args, **kwargs):
+        return cli_configuration_args(
+            self._downloader.params.get('postprocessor_args'),
+            self.pp_key().lower(), *args, **kwargs)
 
 
 class AudioConversionError(PostProcessingError):

youtube_dlc/postprocessor/ffmpeg.py

@@ -239,21 +239,20 @@ class FFmpegPostProcessor(PostProcessor):
         oldest_mtime = min(
             os.stat(encodeFilename(path)).st_mtime for path in input_paths)
 
-        opts += self._configuration_args(exe=self.basename)
-
-        files_cmd = []
-        for path in input_paths:
-            files_cmd.extend([
-                encodeArgument('-i'),
-                encodeFilename(self._ffmpeg_filename_argument(path), True)
-            ])
         cmd = [encodeFilename(self.executable, True), encodeArgument('-y')]
         # avconv does not have repeat option
         if self.basename == 'ffmpeg':
             cmd += [encodeArgument('-loglevel'), encodeArgument('repeat+info')]
-        cmd += (files_cmd
-                + [encodeArgument(o) for o in opts]
-                + [encodeFilename(self._ffmpeg_filename_argument(out_path), True)])
+
+        def make_args(file, pre=[], post=[], *args, **kwargs):
+            args = pre + self._configuration_args(*args, **kwargs) + post
+            return (
+                [encodeArgument(o) for o 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)
 
         self.write_debug('ffmpeg command line: %s' % shell_quote(cmd))
         p = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE, stdin=subprocess.PIPE)

youtube_dlc/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)
+        cmd += self._configuration_args(exe=self._exe_name, use_default_arg='no_compat')
         cmd += ['--', information['id'], filename, temp_filename]
         cmd = [encodeArgument(i) for i in cmd]