[FEATURE] Add custom ffmpeg post processing

src/ytdl_sub/plugins/file_convert.py

@@ -5,11 +5,17 @@ from typing import Optional
 
 from ytdl_sub.entries.entry import Entry
 from ytdl_sub.entries.variables.kwargs import EXT
-from ytdl_sub.plugins.plugin import Plugin
+from ytdl_sub.plugins.plugin import Plugin, PluginPriority
 from ytdl_sub.plugins.plugin import PluginOptions
 from ytdl_sub.utils.exceptions import FileNotDownloadedException
 from ytdl_sub.utils.file_handler import FileMetadata
 from ytdl_sub.validators.audo_codec_validator import FileTypeValidator
+from ytdl_sub.validators.string_formatter_validators import OverridesStringFormatterValidator
+from ytdl_sub.validators.string_select_validator import StringSelectValidator
+
+
+class FileConvertWithValidator(StringSelectValidator):
+    _select_values = {"yt-dlp", "ffmpeg"}
 
 
 class FileConvertOptions(PluginOptions):
@@ -24,9 +30,12 @@ class FileConvertOptions(PluginOptions):
          my_example_preset:
            file_convert:
              convert_to: "mp4"
+             convert_with: "custom"
+             ffmpeg_post_process_args: "asfd"
     """
 
     _required_keys = {"convert_to"}
+    _optional_keys = {"convert_with", "ffmpeg_post_process_args"}
 
     @classmethod
     def partial_validate(cls, name: str, value: Any) -> None:
@@ -39,7 +48,14 @@ class FileConvertOptions(PluginOptions):
 
     def __init__(self, name, value):
         super().__init__(name, value)
-        self._convert_to = self._validate_key(key="convert_to", validator=FileTypeValidator).value
+        self._convert_to: str = self._validate_key(key="convert_to", validator=FileTypeValidator).value
+        self._convert_with: str = self._validate_key_if_present(key="convert_with", validator=FileConvertWithValidator, default="yt-dlp").value
+        self._ffmpeg_post_process_args: Optional[str] = self._validate_key_if_present(key="ffmpeg_post_process_args", validator=OverridesStringFormatterValidator)
+
+        if self._convert_to == "ffmpeg" and not self._ffmpeg_post_process_args:
+            raise self._validation_exception(
+                "Must specify 'ffmpeg_post_process_args' if 'convert_with' is set to ffmpeg"
+            )
 
     @property
     def convert_to(self) -> str:
@@ -51,9 +67,38 @@ class FileConvertOptions(PluginOptions):
         """
         return self._convert_to
 
+    @property
+    def convert_with(self) -> Optional[str]:
+        """
+        Optional. Supports ``yt-dlp`` and ``ffmpeg``. ``yt-dlp`` will convert files within
+        yt-dlp whereas ``ffmpeg`` specifies it will be converted using a custom command specified
+        with ``ffmpeg_post_process_args``. Defaults to ``yt-dlp``.
+
+        """
+        return self._convert_with
+
+    @property
+    def ffmpeg_post_process_args(self) -> Optional[str]:
+        """
+        Optional. ffmpeg args to post-process an entry file with. The args will be inserted in the
+        form of:
+
+        .. code-block:: bash
+
+           ffmpeg -i input_file.ext {ffmpeg_post_process_args) output_file.output_ext
+
+        The output file will use the extension specified in ``convert_to``. Post-processing args
+        can still be set  with ``convert_with`` set to ``yt-dlp``.
+        """
+        return self._ffmpeg_post_process_args
+
 
 class FileConvertPlugin(Plugin[FileConvertOptions]):
     plugin_options_type = FileConvertOptions
+    # Perform this after regex
+    priority: PluginPriority = PluginPriority(
+        modify_entry=PluginPriority.MODIFY_ENTRY_AFTER_SPLIT + 1
+    )
 
     def ytdl_options(self) -> Optional[Dict]:
         """
@@ -88,10 +133,13 @@ class FileConvertPlugin(Plugin[FileConvertOptions]):
             If the audio file is not found
         """
         new_ext = self.plugin_options.convert_to
-        converted_video_file = entry.get_download_file_path().removesuffix(entry.ext) + new_ext
+        converted_video_file_path = entry.get_download_file_path().removesuffix(entry.ext) + new_ext
-        if not self.is_dry_run:
+        if self.plugin_options.convert_with == "yt-dlp":
-            if not os.path.isfile(converted_video_file):
+            if not self.is_dry_run:
-                raise FileNotDownloadedException("Failed to find the converted video file")
+                if not os.path.isfile(converted_video_file_path):
+                    raise FileNotDownloadedException("Failed to find the converted video file")
+        else: # ffmpeg
+
 
         if entry.ext != new_ext:
             entry.add_kwargs(