Add VideoFrame.rotation

Author: lgeiger

av/sidedata/sidedata.pxd

@@ -14,6 +14,8 @@ cdef class SideData(Buffer):
 
 cdef SideData wrap_side_data(Frame frame, int index)
 
+cdef int get_display_rotation(Frame frame)
+
 cdef class _SideDataContainer:
     cdef Frame frame
 

av/sidedata/sidedata.pyx

@@ -1,3 +1,5 @@
+from libc.stdint cimport int32_t
+
 from collections.abc import Mapping
 from enum import Enum
 
@@ -45,13 +47,19 @@ class Type(Enum):
 
 
 cdef SideData wrap_side_data(Frame frame, int index):
-    cdef lib.AVFrameSideDataType type_ = frame.ptr.side_data[index].type
-    if type_ == lib.AV_FRAME_DATA_MOTION_VECTORS:
+    if frame.ptr.side_data[index].type == lib.AV_FRAME_DATA_MOTION_VECTORS:
         return MotionVectors(_cinit_bypass_sentinel, frame, index)
     else:
         return SideData(_cinit_bypass_sentinel, frame, index)
 
 
+cdef int get_display_rotation(Frame frame):
+    for i in range(frame.ptr.nb_side_data):
+        if frame.ptr.side_data[i].type == lib.AV_FRAME_DATA_DISPLAYMATRIX:
+            return int(lib.av_display_rotation_get(<const int32_t *>frame.ptr.side_data[i].data))
+    return 0
+
+
 cdef class SideData(Buffer):
     def __init__(self, sentinel, Frame frame, int index):
         if sentinel is not _cinit_bypass_sentinel:

av/video/frame.pyi

@@ -41,6 +41,8 @@ class VideoFrame(Frame):
     def height(self) -> int: ...
     @property
     def interlaced_frame(self) -> bool: ...
+    @property
+    def rotation(self) -> int: ...
     def __init__(
         self, width: int = 0, height: int = 0, format: str = "yuv420p"
     ) -> None: ...

av/video/frame.pyx

@@ -4,6 +4,7 @@ from enum import IntEnum
 from libc.stdint cimport uint8_t
 
 from av.error cimport err_check
+from av.sidedata.sidedata cimport get_display_rotation
 from av.utils cimport check_ndarray
 from av.video.format cimport get_pix_fmt, get_video_format
 from av.video.plane cimport VideoPlane
@@ -172,6 +173,16 @@ cdef class VideoFrame(Frame):
         """Height of the image, in pixels."""
         return self.ptr.height
 
+    @property
+    def rotation(self):
+        """The rotation component of the `DISPLAYMATRIX` transformation matrix.
+
+        Returns:
+            int: The angle (in degrees) by which the transformation rotates the frame
+                counterclockwise. The angle will be in range [-180, 180].
+        """
+        return get_display_rotation(self)
+
     @property
     def interlaced_frame(self):
         """Is this frame an interlaced or progressive?"""

include/libavutil/avutil.pxd

@@ -4,6 +4,9 @@ from libc.stdint cimport int64_t, uint8_t, uint64_t, int32_t
 cdef extern from "libavutil/mathematics.h" nogil:
     pass
 
+cdef extern from "libavutil/display.h" nogil:
+    cdef double av_display_rotation_get(const int32_t matrix[9])
+
 cdef extern from "libavutil/rational.h" nogil:
     cdef int av_reduce(int *dst_num, int *dst_den, int64_t num, int64_t den, int64_t max)
 

tests/test_decode.py

@@ -155,3 +155,13 @@ def test_flush_decoded_video_frame_count(self) -> None:
             output_count += 1
 
         assert output_count == input_count
+
+    def test_no_side_data(self) -> None:
+        container = av.open(fate_suite("h264/interlaced_crop.mp4"))
+        frame = next(container.decode(video=0))
+        assert frame.rotation == 0
+
+    def test_side_data(self) -> None:
+        container = av.open(fate_suite("mov/displaymatrix.mov"))
+        frame = next(container.decode(video=0))
+        assert frame.rotation == -90