def __init__(
self,
mmap: np.memmap,
width: int,
height: int,
bitdepth: int,
format: VideoFormat,
framerate: int,
):
self.width = width
self.height = height
self.bitdepth = bitdepth
self.framerate = framerate
if isinstance(format, str):
self.format = video_formats[format.lower()]
else:
self.format = format
value_type = bitdepth_to_dtype[bitdepth]
self.dtype = make_dtype(self.format,
value_type=value_type,
width=width,
height=height)
self.data = mmap.view(self.dtype)
self.total_frms = get_num_frms(mmap.size, width, height, format,
value_type)
def readarray(self, size=None, offset=0, dtype=np.uint8, shape=None):
"""
Similar to file.read(), but returns the contents of the underlying
file as a numpy array (or mmap'd array if memmap=True) rather than a
string.
Usually it's best not to use the `size` argument with this method, but
it's provided for compatibility.
"""
if not hasattr(self._file, 'read'):
raise EOFError
if not isinstance(dtype, np.dtype):
dtype = np.dtype(dtype)
if size and size % dtype.itemsize != 0:
raise ValueError('size {} not a multiple of {}'.format(size, dtype))
if isinstance(shape, int):
shape = (shape,)
if not (size or shape):
warnings.warn('No size or shape given to readarray(); assuming a '
'shape of (1,)', AstropyUserWarning)
shape = (1,)
if size and not shape:
shape = (size // dtype.itemsize,)
if size and shape:
actualsize = np.prod(shape) * dtype.itemsize
if actualsize < size:
raise ValueError('size {} is too few bytes for a {} array of '
'{}'.format(size, shape, dtype))
if actualsize < size:
raise ValueError('size {} is too many bytes for a {} array of '
'{}'.format(size, shape, dtype))
filepos = self._file.tell()
try:
if self.memmap:
if self._mmap is None:
# Instantiate Memmap array of the file offset at 0 (so we
# can return slices of it to offset anywhere else into the
# file)
memmap = Memmap(self._file, mode=MEMMAP_MODES[self.mode],
dtype=np.uint8)
# Now we immediately discard the memmap array; we are
# really just using it as a factory function to instantiate
# the mmap object in a convenient way (may later do away
# with this usage)
self._mmap = memmap.base
# Prevent dorking with self._memmap._mmap by memmap.__del__
# in Numpy 1.6 (see
# https://github.com/numpy/numpy/commit/dcc355a0b179387eeba10c95baf2e1eb21d417c7)
memmap._mmap = None
del memmap
return np.ndarray(shape=shape, dtype=dtype, offset=offset,
buffer=self._mmap)
else:
count = reduce(operator.mul, shape)
self._file.seek(offset)
data = _array_from_file(self._file, dtype, count, '')
data.shape = shape
return data
finally:
# Make sure we leave the file in the position we found it; on
# some platforms (e.g. Windows) mmaping a file handle can also
# reset its file pointer
self._file.seek(filepos)
def readarray(self, size=None, offset=0, dtype=np.uint8, shape=None):
"""
Similar to file.read(), but returns the contents of the underlying
file as a numpy array (or mmap'd array if memmap=True) rather than a
string.
Usually it's best not to use the `size` argument with this method, but
it's provided for compatibility.
"""
if not hasattr(self._file, 'read'):
raise EOFError
if not isinstance(dtype, np.dtype):
dtype = np.dtype(dtype)
if size and size % dtype.itemsize != 0:
raise ValueError('size {} not a multiple of {}'.format(size, dtype))
if isinstance(shape, int):
shape = (shape,)
if not (size or shape):
warnings.warn('No size or shape given to readarray(); assuming a '
'shape of (1,)', AstropyUserWarning)
shape = (1,)
if size and not shape:
shape = (size // dtype.itemsize,)
if size and shape:
actualsize = np.prod(shape) * dtype.itemsize
if actualsize < size:
raise ValueError('size {} is too few bytes for a {} array of '
'{}'.format(size, shape, dtype))
if actualsize < size:
raise ValueError('size {} is too many bytes for a {} array of '
'{}'.format(size, shape, dtype))
if self.memmap:
if self._mmap is None:
# Instantiate Memmap array of the file offset at 0
# (so we can return slices of it to offset anywhere else into
# the file)
memmap = Memmap(self._file,
mode=MEMMAP_MODES[self.mode],
dtype=np.uint8)
# Now we immediately discard the memmap array; we are really
# just using it as a factory function to instantiate the mmap
# object in a convenient way (may later do away with this
# usage)
self._mmap = memmap.base
# Prevent dorking with self._memmap._mmap by memmap.__del__ in
# Numpy 1.6 (see
# https://github.com/numpy/numpy/commit/dcc355a0b179387eeba10c95baf2e1eb21d417c7)
memmap._mmap = None
del memmap
return np.ndarray(shape=shape, dtype=dtype, offset=offset,
buffer=self._mmap)
else:
count = reduce(operator.mul, shape)
pos = self._file.tell()
self._file.seek(offset)
data = _array_from_file(self._file, dtype, count, '')
data.shape = shape
self._file.seek(pos)
return data
def readarray(self, size=None, offset=0, dtype=np.uint8, shape=None):
"""
Similar to file.read(), but returns the contents of the underlying
file as a numpy array (or mmap'd array if memmap=True) rather than a
string.
Usually it's best not to use the `size` argument with this method, but
it's provided for compatibility.
"""
if not hasattr(self._file, 'read'):
raise EOFError
if not isinstance(dtype, np.dtype):
dtype = np.dtype(dtype)
if size and size % dtype.itemsize != 0:
raise ValueError('size %d not a multiple of %s' % (size, dtype))
if isinstance(shape, int):
shape = (shape, )
if not (size or shape):
warnings.warn('No size or shape given to readarray(); assuming a '
'shape of (1,)')
shape = (1, )
if size and not shape:
shape = (size // dtype.itemsize, )
if size and shape:
actualsize = np.prod(shape) * dtype.itemsize
if actualsize < size:
raise ValueError('size %d is too few bytes for a %s array of '
'%s' % (size, shape, dtype))
if actualsize < size:
raise ValueError('size %d is too many bytes for a %s array of '
'%s' % (size, shape, dtype))
if self.memmap:
if self._mmap is None:
# Instantiate Memmap array of the file offset at 0
# (so we can return slices of it to offset anywhere else into
# the file)
memmap = Memmap(self._file,
mode=MEMMAP_MODES[self.mode],
dtype=np.uint8)
# Now we immediately discard the memmap array; we are really
# just using it as a factory function to instantiate the mmap
# object in a convenient way (may later do away with this
# usage)
self._mmap = memmap.base
# Prevent dorking with self._memmap._mmap by memmap.__del__ in
# Numpy 1.6 (see
# https://github.com/numpy/numpy/commit/dcc355a0b179387eeba10c95baf2e1eb21d417c7)
memmap._mmap = None
del memmap
return np.ndarray(shape=shape,
dtype=dtype,
offset=offset,
buffer=self._mmap)
else:
count = reduce(lambda x, y: x * y, shape)
pos = self._file.tell()
self._file.seek(offset)
data = _array_from_file(self._file, dtype, count, '')
data.shape = shape
self._file.seek(pos)
return data