image_read_utils.py 文件源码

def _read_from_disk_spatial(fpath, nframes, num_samples=25, start_frame=0,
                            file_prefix='', file_zero_padding=4, file_index=1,
                            dataset_dir='', step=None):
    duration = nframes
    if step is None:
      if num_samples == 1:
          step = tf.random_uniform([1], 0, nframes, dtype='int32')[0]
      else:
          step = tf.cast((duration-tf.constant(1)) /
                         (tf.constant(num_samples-1)), 'int32')
    allimgs = []
    with tf.variable_scope('read_rgb_video'):
        for i in range(num_samples):
            if num_samples == 1:
                i = 1  # so that the random step value can be used
            with tf.variable_scope('read_rgb_image'):
                prefix = file_prefix + '_' if file_prefix else ''
                impath = tf.string_join([
                    tf.constant(dataset_dir + '/'),
                    fpath, tf.constant('/'),
                    prefix,
                    tf.as_string(start_frame + i * step + file_index,
                      width=file_zero_padding, fill='0'),
                    tf.constant('.jpg')])
                img_str = tf.read_file(impath)
            allimgs.append(img_str)
    return allimgs