libtsfuncs is a library for mpeg PSI parsing and generation. https://georgi.unixsol.org/programs/libtsfuncs/

nit_desc.c 6.5KB

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  1. /*
  2. * NIT descriptor generator
  3. * Copyright (C) 2010-2011 Unix Solutions Ltd.
  4. *
  5. * Released under MIT license.
  6. * See LICENSE-MIT.txt for license terms.
  7. */
  8. #include <stdio.h>
  9. #include <unistd.h>
  10. #include <netdb.h>
  11. #include <stdlib.h>
  12. #include <string.h>
  13. #include "tsfuncs.h"
  14. static void ts_nit_regenerate_packet_data(struct ts_nit *nit) {
  15. uint8_t *ts_packets;
  16. int num_packets;
  17. ts_nit_generate(nit, &ts_packets, &num_packets);
  18. memcpy(nit->section_header->packet_data, ts_packets, num_packets * TS_PACKET_SIZE);
  19. nit->section_header->num_packets = num_packets;
  20. free(ts_packets);
  21. }
  22. struct ts_nit *ts_nit_init(struct ts_nit *nit, uint16_t network_id) {
  23. nit->ts_header.pid = 0x10;
  24. nit->ts_header.pusi = 1;
  25. nit->ts_header.payload_field = 1;
  26. nit->ts_header.payload_offset = 4;
  27. nit->section_header->table_id = 0x40;
  28. nit->section_header->version_number = 1;
  29. nit->section_header->current_next_indicator = 1;
  30. nit->section_header->section_syntax_indicator = 1;
  31. nit->section_header->private_indicator = 1;
  32. nit->section_header->section_length = 9 + 4; // Empty section, +4 (16+16) for NIT table data
  33. nit->section_header->ts_id_number = network_id;
  34. nit->section_header->reserved1 = 3;
  35. nit->section_header->reserved2 = 3;
  36. nit->reserved1 = 0xf;
  37. nit->network_info_size = 0; // 16 bits
  38. nit->reserved2 = 0xf;
  39. nit->ts_loop_size = 0; // 16 bits
  40. nit->streams_num = 0;
  41. nit->initialized = 1;
  42. ts_nit_regenerate_packet_data(nit);
  43. return nit;
  44. }
  45. struct ts_nit *ts_nit_alloc_init(uint16_t network_id) {
  46. struct ts_nit *nit = ts_nit_alloc();
  47. if (!nit)
  48. return NULL;
  49. return ts_nit_init(nit, network_id);
  50. }
  51. int ts_nit_add_network_name_descriptor(struct ts_nit *nit, char *network_name) {
  52. if (!network_name || strlen(network_name) > 255)
  53. return 0;
  54. nit->network_info_size = strlen(network_name) + 2;
  55. uint8_t *descriptor = calloc(1, nit->network_info_size);
  56. int dpos = 0;
  57. descriptor[dpos + 0] = 0x40; // Network name descriptor
  58. descriptor[dpos + 1] = nit->network_info_size - 2; // -2 Because of two byte header
  59. dpos += 2;
  60. char *name = network_name;
  61. while (name[0]) {
  62. descriptor[dpos++] = name[0];
  63. name++;
  64. }
  65. nit->network_info = descriptor;
  66. nit->section_header->section_length += nit->network_info_size;
  67. ts_nit_regenerate_packet_data(nit);
  68. return 1;
  69. }
  70. static int ts_nit_add_stream(struct ts_nit *nit, uint16_t ts_id, uint16_t org_net_id, uint8_t *desc, uint8_t desc_size) {
  71. if (nit->streams_num == nit->streams_max - 1 || desc_size == 0) {
  72. FREE(desc);
  73. return 0;
  74. }
  75. int stream_len = 2 + 2 + 1 + 1 + desc_size;
  76. if (stream_len + nit->section_header->section_length > 4093) {
  77. ts_LOGf("NIT no space left, max 4093, current %d will become %d!\n",
  78. nit->section_header->section_length,
  79. stream_len + nit->section_header->section_length);
  80. free(desc);
  81. return 0;
  82. }
  83. nit->ts_loop_size += stream_len;
  84. nit->section_header->section_length += stream_len;
  85. struct ts_nit_stream *sinfo = calloc(1, sizeof(struct ts_nit_stream));
  86. sinfo->transport_stream_id = ts_id; // 2 bytes
  87. sinfo->original_network_id = org_net_id; // 2 bytes
  88. sinfo->reserved1 = 15; // 1 byte
  89. sinfo->descriptor_size = desc_size; // 1 byte
  90. sinfo->descriptor_data = desc; // desc_size bytes
  91. nit->streams[nit->streams_num] = sinfo;
  92. nit->streams_num++;
  93. ts_nit_regenerate_packet_data(nit);
  94. return 1;
  95. }
  96. // freq_type 0 == undefined
  97. // freq_type 1 == satellite
  98. // freq_type 2 == cable
  99. // freq_type 3 == terrestrial
  100. static int ts_nit_add_frequency_list_descriptor(struct ts_nit *nit, uint16_t ts_id, uint16_t org_net_id, uint8_t freq_type, uint32_t *freqs, uint8_t num_freqs) {
  101. uint8_t i;
  102. if (!num_freqs || num_freqs > 63)
  103. return 0;
  104. int desc_size = 2 + 1 + num_freqs * 4; // 2 for header desc header, 1 for coding type, 4 for each frequency
  105. uint8_t *desc = calloc(1, desc_size);
  106. int dpos = 0;
  107. desc[dpos + 0] = 0x62; // frequency_list_descriptor
  108. desc[dpos + 1] = desc_size - 2; // -2 Because of two byte header
  109. desc[dpos + 2] = 0xfc | freq_type; // 6 bits reserved, 2 bits freq_type
  110. dpos += 3;
  111. for(i=0;i<num_freqs;i++) {
  112. uint32_t freq = freqs[i];
  113. desc[dpos + 0] = ((freq &~ 0x00ffffff) >> 24);
  114. desc[dpos + 1] = ((freq &~ 0xff00ffff) >> 16);
  115. desc[dpos + 2] = ((freq &~ 0xffff00ff) >> 8);
  116. desc[dpos + 3] = (freq &~ 0xffffff00);
  117. dpos += 4;
  118. }
  119. return ts_nit_add_stream(nit, ts_id, org_net_id, desc, desc_size);
  120. }
  121. int ts_nit_add_frequency_list_descriptor_cable(struct ts_nit *nit, uint16_t ts_id, uint16_t org_net_id, uint32_t *freqs, uint8_t num_freqs) {
  122. return ts_nit_add_frequency_list_descriptor(nit, ts_id, org_net_id, 2, freqs, num_freqs);
  123. }
  124. int ts_nit_add_cable_delivery_descriptor(struct ts_nit *nit, uint16_t ts_id, uint16_t org_net_id, uint32_t freq, uint8_t modulation, uint32_t symbol_rate) {
  125. int desc_size = 13;
  126. uint8_t *desc = calloc(1, desc_size);
  127. desc[ 0] = 0x44; // cable_delivey_system_descriptor
  128. desc[ 1] = 11; // -2 Because of two byte header
  129. desc[ 2] = ((freq &~ 0x00ffffff) >> 24); // 32 bits, frequency
  130. desc[ 3] = ((freq &~ 0xff00ffff) >> 16);
  131. desc[ 4] = ((freq &~ 0xffff00ff) >> 8);
  132. desc[ 5] = (freq &~ 0xffffff00);
  133. desc[ 6] = 0xff; // 8 bits reserved
  134. desc[ 7] = 0xf0; // 4 bits reserved, 4 bits FEC_outer (0 == not defined)
  135. desc[ 8] = modulation; // 8 bits reserved
  136. desc[ 9] = (symbol_rate >> 20) &~ 0xffffff00; // 28 bits, symbol_rate
  137. desc[10] = (symbol_rate >> 12) &~ 0xffffff00;
  138. desc[11] = (symbol_rate >> 4 ) &~ 0xffffff00;
  139. desc[12] = (symbol_rate &~ 0xfffffff0) << 4; // 4 bits
  140. desc[12] |= 0; // 4 bits FEC_inner (0 == not defined)
  141. return ts_nit_add_stream(nit, ts_id, org_net_id, desc, desc_size);
  142. }
  143. int ts_nit_add_service_list_descriptor(struct ts_nit *nit, uint16_t ts_id, uint16_t org_net_id, uint32_t *services, uint8_t num_services) {
  144. uint8_t i;
  145. if (!num_services || num_services > 85) // 85 * 3 == 255
  146. return 0;
  147. int desc_size = 2 + num_services * 3; // 2 for header desc header, 3 for each service
  148. uint8_t *desc = calloc(1, desc_size);
  149. int dpos = 0;
  150. desc[dpos + 0] = 0x41; // service_list_descriptor
  151. desc[dpos + 1] = desc_size - 2; // -2 Because of two byte header
  152. dpos += 2;
  153. for(i=0;i<num_services;i++) {
  154. uint32_t srv = services[i];
  155. desc[dpos + 0] = (srv &~ 0xff00ffff) >> 16; // service_id (16 bits)
  156. desc[dpos + 1] = (srv &~ 0xffff00ff) >> 8;
  157. desc[dpos + 2] = (srv &~ 0xffffff00); // service_type (8 bits)
  158. dpos += 3;
  159. }
  160. return ts_nit_add_stream(nit, ts_id, org_net_id, desc, desc_size);
  161. }