def jpg_info(filename):
"""
Reads a single jpeg image from the file *filename* and extracts the Axis user data header.
The information it contains is returned as a dict with the keys "hwid", "serial_numer" and
"firmware_version".
"""
if sys.version_info > (3, ):
filename = bytes(filename, "utf8")
m = ffi.new("struct mjpg *")
r = lib.mjpg_open(m, filename, lib.IMTYPE_GRAY, lib.IMORDER_PLANAR)
lib.mjpg_next_head(m)
res = {
'hwid': ffi.string(m.hwid),
'serial_number': ffi.string(m.serial),
'firmware_version': ffi.string(m.firmware),
'timestamp': m.timestamp_sec + m.timestamp_usec / 1000000.0
}
lib.mjpg_close(m)
return res
def decode_frame(self, frm, pixels, pts, grey):
if frm.len == 0:
return 0
m = mjpg_ffi.new("struct mjpg *")
if grey:
r = mjpg_lib.mjpg_open_buffer(m, frm.data, frm.len, mjpg_lib.IMTYPE_GRAY, mjpg_lib.IMORDER_INTERLEAVED)
else:
r = mjpg_lib.mjpg_open_buffer(m, frm.data, frm.len, mjpg_lib.IMTYPE_RGB, mjpg_lib.IMORDER_INTERLEAVED)
if r != mjpg_lib.OK:
raise IOError("Failed to decode frame")
if mjpg_lib.mjpg_next_head(m) != mjpg_lib.OK:
return 0
m.pixels = mjpg_ffi.cast('unsigned char *', pixels)
if mjpg_lib.mjpg_next_data(m) != mjpg_lib.OK:
return 0
pts[0] = m.timestamp_sec * 1000000 + m.timestamp_usec
mjpg_lib.mjpg_close(m)
return 1
def __del__(self):
lib.mjpg_close(self.m)