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286 lines
7.5 KiB
C
286 lines
7.5 KiB
C
/*
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* camutils.c -
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* Copyright (C) 2007 Alessandro Decina
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*
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* Authors:
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* Alessandro Decina <alessandro.d@gmail.com>
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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*
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* You should have received a copy of the GNU Library General Public
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* License along with this library; if not, write to the
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* Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
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* Boston, MA 02110-1301, USA.
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*/
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#include <gst/gst.h>
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#include <string.h>
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#include "cam.h"
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#include "camutils.h"
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#define GST_CAT_DEFAULT cam_debug_cat
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/* From the spec:
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* length_field() {
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* size_indicator
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* if (size_indicator == 0)
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* length_value
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* else if (size_indicator == 1) {
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* length_field_size
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* for (i=0; i<length_field_size; i++) {
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* length_value_byte
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* }
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* }
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* }
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*/
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guint8
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cam_calc_length_field_size (guint length)
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{
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guint field_len;
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if (length < G_MAXUINT8)
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field_len = 1;
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else if (length <= G_MAXUINT16)
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field_len = 3;
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else if (length <= (1 << 24) - 1)
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field_len = 4;
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else
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field_len = 5;
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return field_len;
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}
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/* write a length_field */
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guint8
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cam_write_length_field (guint8 * buff, guint length)
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{
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guint8 field_len = cam_calc_length_field_size (length);
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if (buff) {
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switch (field_len) {
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case 1:
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buff[0] = length;
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break;
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case 2:
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g_return_val_if_reached (0);
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break;
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case 3:
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buff[0] = TPDU_HEADER_SIZE_INDICATOR | (field_len - 1);
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buff[1] = length >> 8;
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buff[2] = length & 0xFF;
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break;
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case 4:
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buff[0] = TPDU_HEADER_SIZE_INDICATOR | (field_len - 1);
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buff[1] = length >> 16;
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buff[2] = (length >> 8) & 0xFF;
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buff[3] = length & 0xFF;
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break;
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case 5:
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buff[0] = TPDU_HEADER_SIZE_INDICATOR | (field_len - 1);
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buff[1] = length >> 24;
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buff[2] = (length >> 16) & 0xFF;
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buff[3] = (length >> 8) & 0xFF;
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buff[4] = length & 0xFF;
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break;
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default:
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g_return_val_if_reached (0);
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}
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}
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return field_len;
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}
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/* read a length_field */
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guint8
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cam_read_length_field (guint8 * buff, guint * length)
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{
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guint i;
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guint field_len;
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guint8 len;
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if (buff[0] <= G_MAXINT8) {
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field_len = 1;
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len = buff[0];
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} else {
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field_len = buff[0] & ~TPDU_HEADER_SIZE_INDICATOR;
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if (field_len > 4) {
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GST_ERROR ("length_field length exceeds 4 bytes: %d", field_len);
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field_len = 0;
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len = 0;
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} else {
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len = 0;
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for (i = 0; i < field_len; ++i)
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len = (len << 8) | *++buff;
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/* count the size indicator byte */
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field_len += 1;
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}
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}
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if (length)
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*length = len;
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return field_len;
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}
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/*
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* ca_pmt () {
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* ca_pmt_tag 24 uimsbf
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* length_field()
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* ca_pmt_list_management 8 uimsbf
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* program_number 16 uimsbf
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* reserved 2 bslbf
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* version_number 5 uimsbf
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* current_next_indicator 1 bslbf
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* reserved 4 bslbf
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* program_info_length 12 uimsbf
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* if (program_info_length != 0) {
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* ca_pmt_cmd_id at program level 8 uimsbf
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* for (i=0; i<n; i++) {
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* CA_descriptor() programme level
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* }
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* }
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* for (i=0; i<n; i++) {
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* stream_type 8 uimsbf
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* reserved 3 bslbf
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* elementary_PID elementary stream PID 13 uimsbf
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* reserved 4 bslbf
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* ES_info_length 12 uimsbf
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* if (ES_info_length != 0) {
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* ca_pmt_cmd_id at ES level 8 uimsbf
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* for (i=0; i<n; i++) {
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* CA_descriptor() elementary stream level
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* }
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* }
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* }
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* }
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*/
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static guint
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get_ca_descriptors_length (GPtrArray * descriptors)
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{
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guint i;
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guint nb_desc = descriptors->len;
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guint len = 0;
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for (i = 0; i < nb_desc; i++) {
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GstMpegtsDescriptor *desc = g_ptr_array_index (descriptors, i);
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if (desc->tag == 0x09)
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len += desc->length;
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}
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return len;
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}
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static guint8 *
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write_ca_descriptors (guint8 * body, GPtrArray * descriptors)
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{
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guint i, nb_desc;
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nb_desc = descriptors->len;
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for (i = 0; i < nb_desc; i++) {
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GstMpegtsDescriptor *desc = g_ptr_array_index (descriptors, i);
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if (desc->tag == 0x09) {
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memcpy (body, desc->data, desc->length);
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body += desc->length;
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}
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}
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return body;
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}
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guint8 *
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cam_build_ca_pmt (GstMpegtsPMT * pmt, guint8 list_management, guint8 cmd_id,
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guint * size)
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{
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GstMpegtsSection *section = (GstMpegtsSection *) pmt;
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guint body_size = 0;
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guint8 *buffer;
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guint8 *body;
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GList *lengths = NULL;
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guint len = 0;
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guint i;
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/* get the length of program level CA_descriptor()s */
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len = get_ca_descriptors_length (pmt->descriptors);
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if (len > 0)
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/* add one byte for the program level cmd_id */
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len += 1;
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lengths = g_list_append (lengths, GINT_TO_POINTER (len));
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body_size += 6 + len;
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for (i = 0; i < pmt->streams->len; i++) {
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GstMpegtsPMTStream *pmtstream = g_ptr_array_index (pmt->streams, i);
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len = get_ca_descriptors_length (pmtstream->descriptors);
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if (len > 0)
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/* one byte for the stream level cmd_id */
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len += 1;
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lengths = g_list_append (lengths, GINT_TO_POINTER (len));
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body_size += 5 + len;
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}
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GST_DEBUG ("Body Size %d", body_size);
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buffer = g_malloc0 (body_size);
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body = buffer;
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/* ca_pmt_list_management 8 uimsbf */
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*body++ = list_management;
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/* program_number 16 uimsbf */
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GST_WRITE_UINT16_BE (body, section->subtable_extension);
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body += 2;
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/* reserved 2
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* version_number 5
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* current_next_indicator 1
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*/
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*body++ = (section->version_number << 1) | 0x01;
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/* Reserved 4
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* program_info_length 12
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*/
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len = GPOINTER_TO_INT (lengths->data);
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lengths = g_list_delete_link (lengths, lengths);
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GST_WRITE_UINT16_BE (body, len);
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body += 2;
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if (len != 0) {
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*body++ = cmd_id;
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body = write_ca_descriptors (body, pmt->descriptors);
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}
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for (i = 0; i < pmt->streams->len; i++) {
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GstMpegtsPMTStream *pmtstream = g_ptr_array_index (pmt->streams, i);
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*body++ = pmtstream->stream_type;
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GST_WRITE_UINT16_BE (body, pmtstream->pid);
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body += 2;
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len = GPOINTER_TO_INT (lengths->data);
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lengths = g_list_delete_link (lengths, lengths);
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GST_WRITE_UINT16_BE (body, len);
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body += 2;
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if (len != 0) {
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*body++ = cmd_id;
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body = write_ca_descriptors (body, pmtstream->descriptors);
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}
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}
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*size = body_size;
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return buffer;
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}
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