Allow the profile of a codec to be set as well as queried

The `profile` property of a stream can now be set. To help applications 
find appropriate profiles, a `profiles` property has been added which 
lists the available profile names.

Author: davidplowman

av/codec/context.pyi

@@ -59,6 +59,8 @@ class CodecContext:
     type: Literal["video", "audio", "data", "subtitle", "attachment"]
     options: dict[str, str]
     profile: str | None
+    @property
+    def profiles(self) -> list[str]: ...
     extradata: bytes | None
     time_base: Fraction
     codec_tag: str

av/codec/context.pyx

@@ -497,10 +497,55 @@ cdef class CodecContext:
     def type(self):
         return self.codec.type
 
+    @property
+    def profiles(self):
+        """
+        List the available profiles for this stream.
+
+        :type: list[str]
+        """
+        ret = []
+        if not self.ptr.codec or not self.codec.desc or not self.codec.desc.profiles:
+            return ret
+
+        # Profiles are always listed in the codec descriptor, but not necessarily in
+        # the codec itself. So use the descriptor here.
+        desc = self.codec.desc
+        cdef int i = 0
+        while desc.profiles[i].profile != lib.FF_PROFILE_UNKNOWN:
+            ret.append(desc.profiles[i].name)
+            i += 1
+
+        return ret
+
     @property
     def profile(self):
-        if self.ptr.codec and lib.av_get_profile_name(self.ptr.codec, self.ptr.profile):
-            return lib.av_get_profile_name(self.ptr.codec, self.ptr.profile)
+        if not self.ptr.codec or not self.codec.desc or not self.codec.desc.profiles:
+            return
+
+        # Profiles are always listed in the codec descriptor, but not necessarily in
+        # the codec itself. So use the descriptor here.
+        desc = self.codec.desc
+        cdef int i = 0
+        while desc.profiles[i].profile != lib.FF_PROFILE_UNKNOWN:
+            if desc.profiles[i].profile == self.ptr.profile:
+                return desc.profiles[i].name
+            i += 1
+
+    @profile.setter
+    def profile(self, value):
+        if not self.codec or not self.codec.desc or not self.codec.desc.profiles:
+            return
+
+        # Profiles are always listed in the codec descriptor, but not necessarily in
+        # the codec itself. So use the descriptor here.
+        desc = self.codec.desc
+        cdef int i = 0
+        while desc.profiles[i].profile != lib.FF_PROFILE_UNKNOWN:
+            if desc.profiles[i].name == value:
+                self.ptr.profile = desc.profiles[i].profile
+                return
+            i += 1
 
     @property
     def time_base(self):

av/stream.pyi

@@ -19,6 +19,7 @@ class Stream:
     codec_context: CodecContext
     metadata: dict[str, str]
     id: int
+    profiles: list[str]
     profile: str
     index: int
     time_base: Fraction | None

av/stream.pyx

@@ -145,6 +145,18 @@ cdef class Stream:
         else:
             self.ptr.id = value
 
+    @property
+    def profiles(self):
+        """
+        List the available profiles for this stream.
+
+        :type: list[str]
+        """
+        if self.codec_context:
+            return self.codec_context.profiles
+        else:
+            return []
+
     @property
     def profile(self):
         """

include/libavcodec/avcodec.pxd

@@ -146,6 +146,9 @@ cdef extern from "libavcodec/avcodec.h" nogil:
         FF_COMPLIANCE_UNOFFICIAL
         FF_COMPLIANCE_EXPERIMENTAL
 
+    cdef enum:
+        FF_PROFILE_UNKNOWN = -99
+
     cdef enum AVCodecID:
         AV_CODEC_ID_NONE
         AV_CODEC_ID_MPEG2VIDEO
@@ -178,12 +181,17 @@ cdef extern from "libavcodec/avcodec.h" nogil:
     cdef int av_codec_is_encoder(AVCodec*)
     cdef int av_codec_is_decoder(AVCodec*)
 
+    cdef struct AVProfile:
+        int profile
+        char *name
+
     cdef struct AVCodecDescriptor:
         AVCodecID id
         char *name
         char *long_name
         int props
         char **mime_types
+        AVProfile *profiles
 
     AVCodecDescriptor* avcodec_descriptor_get(AVCodecID)
 
@@ -266,13 +274,6 @@ cdef extern from "libavcodec/avcodec.h" nogil:
 
     cdef AVClass* avcodec_get_class()
 
-    cdef struct AVCodecDescriptor:
-        AVCodecID id
-        AVMediaType type
-        char *name
-        char *long_name
-        int props
-
     cdef AVCodec* avcodec_find_decoder(AVCodecID id)
     cdef AVCodec* avcodec_find_encoder(AVCodecID id)
 

tests/test_encode.py

@@ -449,3 +449,29 @@ def test_qmin_qmax(self) -> None:
 
         factor = 1.3  # insist at least 30% larger each time
         assert all(small * factor < large for small, large in zip(sizes, sizes[1:]))
+
+
+class TestProfiles(TestCase):
+    def test_profiles(self) -> None:
+        """
+        Test that we can set different encoder profiles.
+        """
+        # Let's try a video and an audio codec.
+        file = io.BytesIO()
+        codecs = (
+            ("h264", 30),
+            ("aac", 48000),
+        )
+
+        for codec_name, rate in codecs:
+            print("Testing:", codec_name)
+            container = av.open(file, mode="w", format="mp4")
+            stream = container.add_stream(codec_name, rate=rate)
+            assert len(stream.profiles) >= 1  # check that we're testing something!
+
+            # It should be enough to test setting and retrieving the code. That means
+            # libav has recognised the profile and set it correctly.
+            for profile in stream.profiles:
+                stream.profile = profile
+                print("Set", profile, "got", stream.profile)
+                assert stream.profile == profile