Add default codec properties

av/container/output.pyi

@@ -19,3 +19,9 @@ class OutputContainer(Container):
     def close(self) -> None: ...
     def mux(self, packets: Packet | Sequence[Packet]) -> None: ...
     def mux_one(self, packet: Packet) -> None: ...
+    @property
+    def default_video_codec(self) -> str: ...
+    @property
+    def default_audio_codec(self) -> str: ...
+    @property
+    def default_subtitle_codec(self) -> str: ...

av/container/output.pyx

@@ -1,6 +1,8 @@
 import logging
 import os
 
+cimport libav as lib
+
 from av.codec.codec cimport Codec
 from av.codec.context cimport CodecContext, wrap_codec_context
 from av.container.streams cimport StreamContainer
@@ -192,6 +194,27 @@ cdef class OutputContainer(Container):
 
         self._started = True
 
+    @property
+    def default_video_codec(self):
+        """
+        Returns the default video codec this container recommends.
+        """
+        return lib.avcodec_get_name(self.format.optr.video_codec)
+
+    @property
+    def default_audio_codec(self):
+        """
+        Returns the default audio codec this container recommends.
+        """
+        return lib.avcodec_get_name(self.format.optr.audio_codec)
+
+    @property
+    def default_subtitle_codec(self):
+        """
+        Returns the default subtitle codec this container recommends.
+        """
+        return lib.avcodec_get_name(self.format.optr.subtitle_codec)
+
     def close(self):
         for stream in self.streams:
             if stream.codec_context:

av/format.pyi

@@ -1,5 +1,7 @@
 __all__ = ("ContainerFormat", "formats_available")
 
+from typing import Literal
+
 from .enum import EnumFlag
 
 class Flags(EnumFlag):
@@ -22,10 +24,12 @@ class Flags(EnumFlag):
     SEEK_TO_PTS: int
 
 class ContainerFormat:
+    def __init__(self, name: str, mode: Literal["r", "w"] | None = None) -> None: ...
     name: str
     long_name: str
     is_input: bool
     is_output: bool
+    extensions: set[str]
 
     # flags
     no_file: int

tests/test_containerformat.py

@@ -1,10 +1,15 @@
-from av import ContainerFormat, formats_available
+from av import ContainerFormat, formats_available, open
 
 from .common import TestCase
 
 
 class TestContainerFormats(TestCase):
-    def test_matroska(self):
+    def test_matroska(self) -> None:
+        with open("test.mkv", "w") as container:
+            self.assertNotEqual(container.default_video_codec, "none")
+            self.assertNotEqual(container.default_audio_codec, "none")
+            self.assertEqual(container.default_subtitle_codec, "ass")
+
         fmt = ContainerFormat("matroska")
         self.assertTrue(fmt.is_input)
         self.assertTrue(fmt.is_output)
@@ -13,7 +18,12 @@ def test_matroska(self):
         self.assertIn("mkv", fmt.extensions)
         self.assertFalse(fmt.no_file)
 
-    def test_mov(self):
+    def test_mov(self) -> None:
+        with open("test.mov", "w") as container:
+            self.assertNotEqual(container.default_video_codec, "none")
+            self.assertNotEqual(container.default_audio_codec, "none")
+            self.assertEqual(container.default_subtitle_codec, "none")
+
         fmt = ContainerFormat("mov")
         self.assertTrue(fmt.is_input)
         self.assertTrue(fmt.is_output)
@@ -22,7 +32,13 @@ def test_mov(self):
         self.assertIn("mov", fmt.extensions)
         self.assertFalse(fmt.no_file)
 
-    def test_stream_segment(self):
+    def test_gif(self) -> None:
+        with open("test.gif", "w") as container:
+            self.assertEqual(container.default_video_codec, "gif")
+            self.assertEqual(container.default_audio_codec, "none")
+            self.assertEqual(container.default_subtitle_codec, "none")
+
+    def test_stream_segment(self) -> None:
         # This format goes by two names, check both.
         fmt = ContainerFormat("stream_segment")
         self.assertFalse(fmt.is_input)
@@ -40,5 +56,5 @@ def test_stream_segment(self):
         self.assertEqual(fmt.extensions, set())
         self.assertTrue(fmt.no_file)
 
-    def test_formats_available(self):
+    def test_formats_available(self) -> None:
         self.assertTrue(formats_available)