292 lines
10 KiB
Python
292 lines
10 KiB
Python
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#!/usr/bin/env python
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# Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
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#
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# Use of this source code is governed by a BSD-style license
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# that can be found in the LICENSE file in the root of the source
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# tree. An additional intellectual property rights grant can be found
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# in the file PATENTS. All contributing project authors may
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# be found in the AUTHORS file in the root of the source tree.
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import optparse
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import os
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import sys
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if __name__ == '__main__':
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# Make sure we always can import helper_functions.
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sys.path.append(os.path.dirname(__file__))
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import helper_functions
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# Chrome browsertests will throw away stderr; avoid that output gets lost.
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sys.stderr = sys.stdout
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def convert_yuv_to_png_files(yuv_file_name, yuv_frame_width, yuv_frame_height,
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output_directory, ffmpeg_path):
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"""Converts a YUV video file into PNG frames.
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The function uses ffmpeg to convert the YUV file. The output of ffmpeg is in
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the form frame_xxxx.png, where xxxx is the frame number, starting from 0001.
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Args:
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yuv_file_name(string): The name of the YUV file.
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yuv_frame_width(int): The width of one YUV frame.
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yuv_frame_height(int): The height of one YUV frame.
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output_directory(string): The output directory where the PNG frames will be
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stored.
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ffmpeg_path(string): The path to the ffmpeg executable. If None, the PATH
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will be searched for it.
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Return:
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(bool): True if the conversion was OK.
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"""
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size_string = str(yuv_frame_width) + 'x' + str(yuv_frame_height)
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output_files_pattern = os.path.join(output_directory, 'frame_%04d.png')
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if not ffmpeg_path:
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ffmpeg_path = 'ffmpeg.exe' if sys.platform == 'win32' else 'ffmpeg'
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command = [ffmpeg_path, '-s', '%s' % size_string, '-i', '%s'
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% yuv_file_name, '-f', 'image2', '-vcodec', 'png',
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'%s' % output_files_pattern]
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try:
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print 'Converting YUV file to PNG images (may take a while)...'
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print ' '.join(command)
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helper_functions.run_shell_command(
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command, fail_msg='Error during YUV to PNG conversion')
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except helper_functions.HelperError, err:
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print 'Error executing command: %s. Error: %s' % (command, err)
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return False
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except OSError:
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print 'Did not find %s. Have you installed it?' % ffmpeg_path
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return False
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return True
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def decode_frames(input_directory, zxing_path):
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"""Decodes the barcodes overlaid in each frame.
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The function uses the Zxing command-line tool from the Zxing C++ distribution
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to decode the barcode in every PNG frame from the input directory. The frames
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should be named frame_xxxx.png, where xxxx is the frame number. The frame
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numbers should be consecutive and should start from 0001.
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The decoding results in a frame_xxxx.txt file for every successfully decoded
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barcode. This file contains the decoded barcode as 12-digit string (UPC-A
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format: 11 digits content + one check digit).
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Args:
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input_directory(string): The input directory from where the PNG frames are
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read.
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zxing_path(string): The path to the zxing binary. If specified as None,
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the PATH will be searched for it.
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Return:
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(bool): True if the decoding succeeded.
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"""
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if not zxing_path:
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zxing_path = 'zxing.exe' if sys.platform == 'win32' else 'zxing'
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print 'Decoding barcodes from PNG files with %s...' % zxing_path
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return helper_functions.perform_action_on_all_files(
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directory=input_directory, file_pattern='frame_',
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file_extension='png', start_number=1, action=_decode_barcode_in_file,
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command_line_decoder=zxing_path)
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def _decode_barcode_in_file(file_name, command_line_decoder):
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"""Decodes the barcode in the upper left corner of a PNG file.
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Args:
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file_name(string): File name of the PNG file.
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command_line_decoder(string): The ZXing command-line decoding tool.
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Return:
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(bool): True upon success, False otherwise.
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"""
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command = [command_line_decoder, '--try-harder', '--dump-raw', file_name]
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try:
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out = helper_functions.run_shell_command(
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command, fail_msg='Error during decoding of %s' % file_name)
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text_file = open('%s.txt' % file_name[:-4], 'w')
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text_file.write(out)
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text_file.close()
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except helper_functions.HelperError, err:
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print 'Barcode in %s cannot be decoded.' % file_name
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print err
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return False
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except OSError:
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print 'Did not find %s. Have you installed it?' % command_line_decoder
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return False
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return True
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def _generate_stats_file(stats_file_name, input_directory='.'):
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"""Generate statistics file.
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The function generates a statistics file. The contents of the file are in the
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format <frame_name> <barcode>, where frame name is the name of every frame
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(effectively the frame number) and barcode is the decoded barcode. The frames
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and the helper .txt files are removed after they have been used.
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"""
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file_prefix = os.path.join(input_directory, 'frame_')
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stats_file = open(stats_file_name, 'w')
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print 'Generating stats file: %s' % stats_file_name
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for i in range(1, _count_frames_in(input_directory=input_directory) + 1):
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frame_number = helper_functions.zero_pad(i)
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barcode_file_name = file_prefix + frame_number + '.txt'
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png_frame = file_prefix + frame_number + '.png'
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entry_frame_number = helper_functions.zero_pad(i-1)
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entry = 'frame_' + entry_frame_number + ' '
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if os.path.isfile(barcode_file_name):
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barcode = _read_barcode_from_text_file(barcode_file_name)
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os.remove(barcode_file_name)
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if _check_barcode(barcode):
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entry += (helper_functions.zero_pad(int(barcode[0:11])) + '\n')
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else:
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entry += 'Barcode error\n' # Barcode is wrongly detected.
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else: # Barcode file doesn't exist.
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entry += 'Barcode error\n'
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stats_file.write(entry)
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os.remove(png_frame)
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stats_file.close()
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def _read_barcode_from_text_file(barcode_file_name):
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"""Reads the decoded barcode for a .txt file.
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Args:
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barcode_file_name(string): The name of the .txt file.
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Return:
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(string): The decoded barcode.
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"""
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barcode_file = open(barcode_file_name, 'r')
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barcode = barcode_file.read()
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barcode_file.close()
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return barcode
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def _check_barcode(barcode):
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"""Check weather the UPC-A barcode was decoded correctly.
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This function calculates the check digit of the provided barcode and compares
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it to the check digit that was decoded.
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Args:
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barcode(string): The barcode (12-digit).
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Return:
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(bool): True if the barcode was decoded correctly.
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"""
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if len(barcode) != 12:
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return False
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r1 = range(0, 11, 2) # Odd digits
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r2 = range(1, 10, 2) # Even digits except last
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dsum = 0
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# Sum all the even digits
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for i in r1:
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dsum += int(barcode[i])
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# Multiply the sum by 3
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dsum *= 3
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# Add all the even digits except the check digit (12th digit)
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for i in r2:
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dsum += int(barcode[i])
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# Get the modulo 10
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dsum = dsum % 10
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# If not 0 substract from 10
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if dsum != 0:
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dsum = 10 - dsum
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# Compare result and check digit
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return dsum == int(barcode[11])
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def _count_frames_in(input_directory='.'):
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"""Calculates the number of frames in the input directory.
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The function calculates the number of frames in the input directory. The
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frames should be named frame_xxxx.png, where xxxx is the number of the frame.
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The numbers should start from 1 and should be consecutive.
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Args:
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input_directory(string): The input directory.
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Return:
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(int): The number of frames.
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"""
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file_prefix = os.path.join(input_directory, 'frame_')
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file_exists = True
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num = 1
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while file_exists:
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file_name = (file_prefix + helper_functions.zero_pad(num) + '.png')
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if os.path.isfile(file_name):
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num += 1
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else:
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file_exists = False
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return num - 1
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def _parse_args():
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"""Registers the command-line options."""
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usage = "usage: %prog [options]"
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parser = optparse.OptionParser(usage=usage)
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parser.add_option('--zxing_path', type='string',
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help=('The path to where the zxing executable is located. '
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'If omitted, it will be assumed to be present in the '
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'PATH with the name zxing[.exe].'))
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parser.add_option('--ffmpeg_path', type='string',
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help=('The path to where the ffmpeg executable is located. '
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'If omitted, it will be assumed to be present in the '
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'PATH with the name ffmpeg[.exe].'))
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parser.add_option('--yuv_frame_width', type='int', default=640,
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help='Width of the YUV file\'s frames. Default: %default')
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parser.add_option('--yuv_frame_height', type='int', default=480,
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help='Height of the YUV file\'s frames. Default: %default')
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parser.add_option('--yuv_file', type='string', default='output.yuv',
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help='The YUV file to be decoded. Default: %default')
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parser.add_option('--stats_file', type='string', default='stats.txt',
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help='The output stats file. Default: %default')
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parser.add_option('--png_working_dir', type='string', default='.',
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help=('The directory for temporary PNG images to be stored '
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'in when decoding from YUV before they\'re barcode '
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'decoded. If using Windows and a Cygwin-compiled '
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'zxing.exe, you should keep the default value to '
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'avoid problems. Default: %default'))
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options, _ = parser.parse_args()
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return options
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def _main():
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"""The main function.
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A simple invocation is:
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./webrtc/tools/barcode_tools/barcode_decoder.py
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--yuv_file=<path_and_name_of_overlaid_yuv_video>
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--yuv_frame_width=640 --yuv_frame_height=480
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--stats_file=<path_and_name_to_stats_file>
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"""
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options = _parse_args()
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# Convert the overlaid YUV video into a set of PNG frames.
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if not convert_yuv_to_png_files(options.yuv_file, options.yuv_frame_width,
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options.yuv_frame_height,
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output_directory=options.png_working_dir,
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ffmpeg_path=options.ffmpeg_path):
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print 'An error occurred converting from YUV to PNG frames.'
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return -1
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# Decode the barcodes from the PNG frames.
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if not decode_frames(input_directory=options.png_working_dir,
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zxing_path=options.zxing_path):
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print 'An error occurred decoding barcodes from PNG frames.'
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return -2
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# Generate statistics file.
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_generate_stats_file(options.stats_file,
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input_directory=options.png_working_dir)
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print 'Completed barcode decoding.'
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return 0
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if __name__ == '__main__':
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sys.exit(_main())
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