public void start_pass(J_BUF_MODE pass_mode)
{
if (pass_mode != J_BUF_MODE.JBUF_PASS_THRU)
m_cinfo.ERREXIT(J_MESSAGE_CODE.JERR_BAD_BUFFER_MODE);
/* Initialize total-height counter for detecting bottom of image */
m_rows_to_go = m_cinfo.m_image_height;
/* Mark the conversion buffer empty */
m_next_buf_row = 0;
/* Preset additional state variables for context mode.
* These aren't used in non-context mode, so we needn't test which mode.
*/
m_this_row_group = 0;
/* Set next_buf_stop to stop after two row groups have been read in. */
m_next_buf_stop = 2 * m_cinfo.m_max_v_samp_factor;
}