CVPixelBufferCreate in Python

cvpixelbuffercreate.py

import ctypes
import ctypes.util
import objc


# MacTypes.h

# typedef UInt32 FourCharCode
FourCharCode = ctypes.c_uint32
# typedef FourCharCode OSType;
OSType = FourCharCode


# Core Foundation

CF = ctypes.CDLL(ctypes.util.find_library('CoreFoundation'))


class __CFAllocator(ctypes.Structure):
    pass


CF.CFAllocatorRef = ctypes.POINTER(__CFAllocator)

CF.kCFAllocatorDefault = None


class __CFDictionary(ctypes.Structure):
    pass


CF.CFDictionaryRef = ctypes.POINTER(__CFDictionary)


# Core Video

CV = ctypes.CDLL(ctypes.util.find_library('CoreVideo'))

CV.CVReturn = ctypes.c_int32
CV.kCVReturnSuccess = 0
CV.kCVPixelFormatType_32BGRA = 0x42475241  # 'ARGB'


class __CVBuffer(ctypes.Structure):
    pass


CV.CVBufferRef = ctypes.POINTER(__CVBuffer)
CV.CVImageBufferRef = CV.CVBufferRef
CV.CVPixelBufferRef = CV.CVImageBufferRef

# CVReturn CVPixelBufferCreate(
#     CFAllocatorRef allocator,
#     size_t width,
#     size_t height,
#     OSType pixelFormatType,
#     CFDictionaryRef pixelBufferAttributes,
#     CVPixelBufferRef  _Nullable *pixelBufferOut
# );
CV.CVPixelBufferCreate.restype = CV.CVReturn
CV.CVPixelBufferCreate.argtypes = [
    CF.CFAllocatorRef,
    ctypes.c_size_t,
    ctypes.c_size_t,
    OSType,
    CF.CFDictionaryRef,
    ctypes.POINTER(CV.CVPixelBufferRef),
]

# CVPixelBufferRef CVPixelBufferRetain(CVPixelBufferRef texture);
CV.CVPixelBufferRetain.restype = CV.CVPixelBufferRef
CV.CVPixelBufferRetain.argtypes = [CV.CVPixelBufferRef]

# void CVPixelBufferRelease(CVPixelBufferRef texture);
CV.CVPixelBufferRelease.restype = None
CV.CVPixelBufferRelease.argtypes = [CV.CVPixelBufferRef]


def cv_pixel_buffer_create(
    width: int,
    height: int,
    pixel_format_type: OSType,
) -> CV.CVPixelBufferRef:
    pixel_buffer_ref = CV.CVPixelBufferRef()
    status = CV.CVPixelBufferCreate(
        CF.kCFAllocatorDefault,
        width,
        height,
        pixel_format_type,
        None,
        ctypes.byref(pixel_buffer_ref)
    )
    CV.CVPixelBufferRetain(pixel_buffer_ref)
    if status == CV.kCVReturnSuccess:
        return objc.objc_object(
            c_void_p=ctypes.cast(pixel_buffer_ref, ctypes.c_void_p)
        )
    return None


def cv_pixel_buffer_release(self: CV.CVPixelBufferRef) -> None:
    CV.CVPixelBufferRelease(self)


CV.CVPixelBufferRef.__del__ = cv_pixel_buffer_release


if __name__ == '__main__':

    while True:
        pixel_buffer = cv_pixel_buffer_create(
            640,
            480,
            CV.kCVPixelFormatType_32BGRA,
        )
        print('***', pixel_buffer)
        del pixel_buffer