diff --git a/av/container/output.pyx b/av/container/output.pyx
index 616d40ae6..fbe163bc1 100644
--- a/av/container/output.pyx
+++ b/av/container/output.pyx
@@ -4,9 +4,6 @@ from fractions import Fraction
 
 cimport libav as lib
 
-from libc.string cimport memcpy
-from libc.stdint cimport uint8_t
-
 from av.codec.codec cimport Codec
 from av.codec.context cimport CodecContext, wrap_codec_context
 from av.container.streams cimport StreamContainer
@@ -251,59 +248,6 @@ cdef class OutputContainer(Container):
         return py_stream
 
 
-    def add_attachment(self, file_data, filename, mimetype=None):
-        """Add a file as an attachment stream."""
-        cdef lib.AVStream *stream
-        cdef size_t data_len
-        cdef uint8_t *attachment
-        cdef Stream py_stream
-
-        if not isinstance(file_data, bytes):
-            raise TypeError("file_data must be bytes")
-
-        if not filename:
-            raise ValueError("filename must be provided")
-
-        # Create new stream without codec
-        stream = lib.avformat_new_stream(self.ptr, NULL)
-        if stream == NULL:
-            raise MemoryError("Could not allocate stream")
-
-        try:
-            # Mark as attachment type
-            stream.codecpar.codec_type = lib.AVMEDIA_TYPE_ATTACHMENT
-
-            # Allocate and copy attachment data
-            data_len = len(file_data)
-            attachment = <uint8_t*>lib.av_malloc(data_len)
-            if attachment == NULL:
-                raise MemoryError("Could not allocate attachment buffer")
-
-            # Copy the data
-            memcpy(attachment, <uint8_t*>file_data, data_len)
-
-            # Store attachment in codecpar extradata
-            stream.codecpar.extradata = attachment
-            stream.codecpar.extradata_size = data_len
-
-            # Add metadata
-            err_check(lib.av_dict_set(&stream.metadata, "filename", filename.encode('utf-8'), 0))
-            err_check(lib.av_dict_set(&stream.metadata, "mimetype", mimetype.encode('utf-8'), 0))
-
-            # Explicitly set time_base to avoid duration issues
-            stream.time_base.num = 1
-            stream.time_base.den = 1
-
-            # Create Python stream object
-            py_stream = wrap_stream(self, stream, None)
-            self.streams.add_stream(py_stream)
-
-            return py_stream
-
-        except Exception:
-            lib.av_free(attachment)
-            raise
-
     cpdef start_encoding(self):
         """Write the file header! Called automatically."""
 
diff --git a/av/stream.pyi b/av/stream.pyi
index 82bb672b2..a2a2e439c 100644
--- a/av/stream.pyi
+++ b/av/stream.pyi
@@ -1,9 +1,31 @@
+from enum import Flag
 from fractions import Fraction
 from typing import Literal
 
 from .codec import Codec, CodecContext
 from .container import Container
 
+class Disposition(Flag):
+    default: int
+    dub: int
+    original: int
+    comment: int
+    lyrics: int
+    karaoke: int
+    forced: int
+    hearing_impaired: int
+    visual_impaired: int
+    clean_effects: int
+    attached_pic: int
+    timed_thumbnails: int
+    non_diegetic: int
+    captions: int
+    descriptions: int
+    metadata: int
+    dependent: int
+    still_image: int
+    multilayer: int
+
 class Stream:
     name: str | None
     container: Container
@@ -20,6 +42,7 @@ class Stream:
     guessed_rate: Fraction | None
     start_time: int | None
     duration: int | None
+    disposition: Disposition
     frames: int
     language: str | None
     type: Literal["video", "audio", "data", "subtitle", "attachment"]
diff --git a/av/stream.pyx b/av/stream.pyx
index 35b85acdf..d0ecf37ad 100644
--- a/av/stream.pyx
+++ b/av/stream.pyx
@@ -1,6 +1,6 @@
 cimport libav as lib
 
-from enum import Enum
+from enum import Flag
 
 from av.error cimport err_check
 from av.packet cimport Packet
@@ -12,6 +12,28 @@ from av.utils cimport (
 )
 
 
+class Disposition(Flag):
+    default = 1 << 0
+    dub = 1 << 1
+    original = 1 << 2
+    comment = 1 << 3
+    lyrics = 1 << 4
+    karaoke = 1 << 5
+    forced = 1 << 6
+    hearing_impaired = 1 << 7
+    visual_impaired = 1 << 8
+    clean_effects = 1 << 9
+    attached_pic = 1 << 10
+    timed_thumbnails = 1 << 11
+    non_diegetic = 1 << 12
+    captions = 1 << 16
+    descriptions = 1 << 17
+    metadata = 1 << 18
+    dependent = 1 << 19
+    still_image = 1 << 20
+    multilayer = 1 << 21
+
+
 cdef object _cinit_bypass_sentinel = object()
 
 cdef Stream wrap_stream(Container container, lib.AVStream *c_stream, CodecContext codec_context):
@@ -96,6 +118,9 @@ cdef class Stream:
         if name == "id":
             self._set_id(value)
             return
+        if name == "disposition":
+            self.ptr.disposition = value
+            return
 
         # Convenience setter for codec context properties.
         if self.codec_context is not None:
@@ -230,6 +255,10 @@ cdef class Stream:
         """
         return self.metadata.get("language")
 
+    @property
+    def disposition(self):
+        return Disposition(self.ptr.disposition)
+
     @property
     def type(self):
         """
diff --git a/include/libav.pxd b/include/libav.pxd
index 716a58195..568913208 100644
--- a/include/libav.pxd
+++ b/include/libav.pxd
@@ -23,10 +23,6 @@ include "libavfilter/buffersink.pxd"
 include "libavfilter/buffersrc.pxd"
 
 
-cdef extern from "libavutil/mem.h":
-    void* av_malloc(size_t size) nogil
-    void av_free(void* ptr) nogil
-
 cdef extern from "stdio.h" nogil:
     cdef int snprintf(char *output, int n, const char *format, ...)
     cdef int vsnprintf(char *output, int n, const char *format, va_list args)
diff --git a/tests/test_colorspace.py b/tests/test_colorspace.py
index 7574c147d..c76416c80 100644
--- a/tests/test_colorspace.py
+++ b/tests/test_colorspace.py
@@ -31,6 +31,8 @@ def test_sky_timelapse() -> None:
     )
     stream = container.streams.video[0]
 
+    assert stream.disposition == av.stream.Disposition.default
+
     assert stream.codec_context.color_range == 1
     assert stream.codec_context.color_range == ColorRange.MPEG
     assert stream.codec_context.color_primaries == 1