Variant of cr2_embed

Initial version, replaces only IFD#3 with supplied encoded sensor image

cr2_replace.py

@@ -0,0 +1,73 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+#
+# Copyright © 2015-2018 Johann A. Briffa
+#
+# This file is part of CR2_Scripts.
+#
+# CR2_Scripts is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# CR2_Scripts is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with CR2_Scripts.  If not, see <https://www.gnu.org/licenses/>.
+
+import sys
+import os
+import argparse
+
+sys.path.append(os.path.join(os.path.dirname(os.path.realpath(__file__)),'pyshared'))
+import jbtiff
+
+## main program
+
+def main():
+   # interpret user options
+   parser = argparse.ArgumentParser()
+   parser.add_argument("-i", "--input", required=True,
+                     help="input raw file to use as basis")
+   parser.add_argument("-s", "--sensor", required=True,
+                     help="sensor image file to replace input")
+   parser.add_argument("-o", "--output", required=True,
+                     help="output CR2 file")
+   args = parser.parse_args()
+
+   # read input raw file
+   tiff = jbtiff.tiff_file(open(args.input, 'rb'))
+   # replace data strips for main sensor image (IFD#3)
+   k = 3
+   IFD, ifd_offset, strips = tiff.data[k]
+
+   # read input data file
+   with open(args.sensor, 'rb') as fid:
+      data = fid.read()
+   print "IFD#%d: Replacing data strip with length %d" % (k, len(data))
+   # replace data strips with new data
+   assert strips
+   del strips[:]
+   strips.append(data)
+   # update IFD data
+   if 273 in IFD:
+      assert 279 in IFD
+      assert 513 not in IFD and 514 not in IFD
+      IFD[279] = (4, 1, [len(data)], 0)
+   elif 513 in IFD:
+      assert 514 in IFD
+      assert 273 not in IFD and 279 not in IFD
+      IFD[514] = (4, 1, [len(data)], 0)
+   else:
+      raise AssertionError("Reference to data strip not found in IFD#%d" % k)
+
+   # save updated CR2 file
+   tiff.write(open(args.output,'wb'))
+   return
+
+# main entry point
+if __name__ == '__main__':
+   main()