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#!/usr/bin/env python3
# -*- coding: utf-8 -*-
# Copyright 2020 Daniel Estevez <daniel@destevez.net>
#
# This file is part of gr-satellites
#
# SPDX-License-Identifier: GPL-3.0-or-later
#
import struct
from .imagereceiver import ImageReceiver
class ImageReceiverK2SAT(ImageReceiver):
def __init__(self, *args, **kwargs):
super().__init__(*args, **kwargs)
self._last_frame_count = None
self._unwrap = 0
self._first_header_frame_count = None
def _first_header_pointer(self, chunk):
return chunk[16 + 3]
def _virtual_channel_frame_count(self, chunk):
return chunk[16 + 2]
def _unwrapped_frame_count(self, chunk):
fc = self._virtual_channel_frame_count(chunk) + self._unwrap
if self._last_frame_count is not None and fc < self._last_frame_count:
self._unwrap += 256
fc += 256
self._last_frame_count = fc
return fc
def chunk_sequence(self, chunk):
fh = self._first_header_pointer(chunk)
if fh == 0x00:
# First packet in image
self._first_header_frame_count = self._unwrapped_frame_count(chunk)
return 0
return (self._unwrapped_frame_count(chunk)
- self._first_header_frame_count
if self._first_header_frame_count is not None
else None)
def is_last_chunk(self, chunk):
# 0xff indicates last packet in image
return self._first_header_pointer(chunk) == 0xff
def chunk_data(self, chunk):
return chunk[20:-1]
def filename(self, fid):
return f'{fid}.jpg'
def parse_chunk(self, chunk):
return chunk if len(chunk) > 16 + 4 + 1 else None
k2sat = ImageReceiverK2SAT
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