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#!/usr/bin/env python
# Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
# Use of this source code is governed by a BSD-style license
# that can be found in the LICENSE file in the root of the source
# tree. An additional intellectual property rights grant can be found
# in the file PATENTS. All contributing project authors may
# be found in the AUTHORS file in the root of the source tree.
import optparse
import os
import sys
def _CropOneFrame(yuv_file, output_file, component_sizes):
"""Crops one frame.
This function crops one frame going through all the YUV planes and cropping
respective amount of rows.
yuv_file(file): The opened (for binary reading) YUV file.
output_file(file): The opened (for binary writing) file.
component_sizes(list of 3 3-ples): The list contains the sizes for all the
planes (Y, U, V) of the YUV file plus the crop_height scaled for every
plane. The sizes equal width, height and crop_height for the Y plane,
and are equal to width/2, height/2 and crop_height/2 for the U and V
(bool): True if there are more frames to crop, False otherwise.
for comp_width, comp_height, comp_crop_height in component_sizes:
for row in range(comp_height):
# Read the plane data for this row.
yuv_plane =
# If the plane is empty, we have reached the end of the file.
if yuv_plane == "":
return False
# Only write the plane data for the rows bigger than crop_height.
if row >= comp_crop_height:
return True
def CropFrames(yuv_file_name, output_file_name, width, height, crop_height):
"""Crops rows of pixels from the top of the YUV frames.
This function goes through all the frames in a video and crops the crop_height
top pixel rows of every frame.
yuv_file_name(string): The name of the YUV file to be cropped.
output_file_name(string): The name of the output file where the result will
be written.
width(int): The width of the original YUV file.
height(int): The height of the original YUV file.
crop_height(int): The height (the number of pixel rows) to be cropped from
the frames.
# Component sizes = [Y_sizes, U_sizes, V_sizes].
component_sizes = [(width, height, crop_height),
(width/2, height/2, crop_height/2),
(width/2, height/2, crop_height/2)]
yuv_file = open(yuv_file_name, 'rb')
output_file = open(output_file_name, 'wb')
data_left = True
while data_left:
data_left = _CropOneFrame(yuv_file, output_file, component_sizes)
def _ParseArgs():
"""Registers the command-line options."""
usage = "usage: %prog [options]"
parser = optparse.OptionParser(usage=usage)
parser.add_option('--width', type='int',
help=('Width of the YUV file\'s frames. '
'Default: %default'))
parser.add_option('--height', type='int', default=288,
help=('Height of the YUV file\'s frames. '
'Default: %default'))
parser.add_option('--crop_height', type='int', default=32,
help=('How much of the top of the YUV file to crop. '
'Has to be module of 2. Default: %default'))
parser.add_option('--yuv_file', type='string',
help=('The YUV file to be cropped.'))
parser.add_option('--output_file', type='string', default='output.yuv',
help=('The output YUV file containing the cropped YUV. '
'Default: %default'))
options = parser.parse_args()[0]
if not options.yuv_file:
parser.error('yuv_file argument missing. Please specify input YUV file!')
return options
def main():
"""A tool to crop rows of pixels from the top part of a YUV file.
A simple invocation will be:
./ --width=640 --height=480 --crop_height=32
--output_yuv=<path and name_of_output_file>
options = _ParseArgs()
if os.path.getsize(options.yuv_file) == 0:
sys.stderr.write('Error: The YUV file you have passed has size 0. The '
'produced output will also have size 0.\n')
return -1
CropFrames(options.yuv_file, options.output_file, options.width,
options.height, options.crop_height)
return 0
if __name__ == '__main__':