Add container.supported_codecs

av/container/output.pyi

@@ -25,3 +25,5 @@ class OutputContainer(Container):
     def default_audio_codec(self) -> str: ...
     @property
     def default_subtitle_codec(self) -> str: ...
+    @property
+    def supported_codecs(self) -> set[str]: ...

av/container/output.pyx

@@ -194,6 +194,26 @@ cdef class OutputContainer(Container):
 
         self._started = True
 
+    @property
+    def supported_codecs(self):
+        """
+        Returns a set of all codecs this format supports.
+        """
+        result = set()
+        cdef const lib.AVCodec *codec = NULL
+        cdef void *opaque = NULL
+
+        while True:
+            codec = lib.av_codec_iterate(&opaque)
+            if codec == NULL:
+                break
+
+            if lib.avformat_query_codec(self.ptr.oformat, codec.id, lib.FF_COMPLIANCE_NORMAL) == 1:
+                result.add(codec.name)
+
+        return result
+
+
     @property
     def default_video_codec(self):
         """

include/libavcodec/avcodec.pxd

@@ -1,15 +1,14 @@
 from libc.stdint cimport int8_t, int64_t, uint16_t, uint32_t
 
+cdef extern from "libavcodec/codec.h":
+    struct AVCodecTag:
+        pass
+
+cdef extern from "libavcodec/codec_id.h":
+    AVCodecID av_codec_get_id(const AVCodecTag *const *tags, uint32_t tag)
+
 
 cdef extern from "libavcodec/avcodec.h" nogil:
-    """
-    // AV_FRAME_DATA_SEI_UNREGISTERED available since version 56.54.100 of libavutil (FFmpeg >= 4.4)
-    #define HAS_AV_FRAME_DATA_SEI_UNREGISTERED  (LIBAVUTIL_VERSION_INT >= 3683940)
-
-    #if !HAS_AV_FRAME_DATA_SEI_UNREGISTERED
-        #define AV_FRAME_DATA_SEI_UNREGISTERED -1
-    #endif
-    """
     cdef set pyav_get_available_codecs()
 
     cdef int   avcodec_version()

include/libavformat/avformat.pxd

@@ -115,6 +115,8 @@ cdef extern from "libavformat/avformat.h" nogil:
         # const AVCodecTag* const *codec_tag
         const AVClass *priv_class
 
+    int avformat_query_codec(const AVOutputFormat *oformat, AVCodecID codec_id, int std_compliance)
+
     # AVInputFormat.flags and AVOutputFormat.flags
     cdef enum:
         AVFMT_NOFILE

tests/test_containerformat.py

@@ -9,6 +9,7 @@ def test_matroska(self) -> None:
             self.assertNotEqual(container.default_video_codec, "none")
             self.assertNotEqual(container.default_audio_codec, "none")
             self.assertEqual(container.default_subtitle_codec, "ass")
+            self.assertIn("ass", container.supported_codecs)
 
         fmt = ContainerFormat("matroska")
         self.assertTrue(fmt.is_input)
@@ -23,6 +24,7 @@ def test_mov(self) -> None:
             self.assertNotEqual(container.default_video_codec, "none")
             self.assertNotEqual(container.default_audio_codec, "none")
             self.assertEqual(container.default_subtitle_codec, "none")
+            self.assertIn("h264", container.supported_codecs)
 
         fmt = ContainerFormat("mov")
         self.assertTrue(fmt.is_input)
@@ -37,6 +39,7 @@ def test_gif(self) -> None:
             self.assertEqual(container.default_video_codec, "gif")
             self.assertEqual(container.default_audio_codec, "none")
             self.assertEqual(container.default_subtitle_codec, "none")
+            self.assertIn("gif", container.supported_codecs)
 
     def test_stream_segment(self) -> None:
         # This format goes by two names, check both.