int conditional_access_section_read(conditional_access_section_t *cas, uint8_t *buf, size_t buf_len, uint32_t payload_unit_start_indicator, psi_table_buffer_t *catBuffer) { if (cas == NULL || buf == NULL) { SAFE_REPORT_TS_ERR(-1); return 0; } bs_t *b = NULL; if (!payload_unit_start_indicator && catBuffer->buffer == NULL) { // this TS packet is not start of table, and we have no cached table data LOG_WARN ("conditional_access_section_read: payload_unit_start_indicator not set and no cached data"); return 0; } if (payload_unit_start_indicator) { uint8_t payloadStartPtr = buf[0]; buf += (payloadStartPtr + 1); buf_len -= (payloadStartPtr + 1); LOG_DEBUG_ARGS ("conditional_access_section_read: payloadStartPtr = %d", payloadStartPtr); } // check for pat spanning multiple TS packets if (catBuffer->buffer != NULL) { LOG_DEBUG_ARGS ("conditional_access_section_read: catBuffer detected: catBufferAllocSz = %d, catBufferUsedSz = %d", catBuffer->bufferAllocSz, catBuffer->bufferUsedSz); size_t numBytesToCopy = buf_len; if (buf_len > (catBuffer->bufferAllocSz - catBuffer->bufferUsedSz)) { numBytesToCopy = catBuffer->bufferAllocSz - catBuffer->bufferUsedSz; } LOG_DEBUG_ARGS ("conditional_access_section_read: copying %d bytes to catBuffer", numBytesToCopy); memcpy (catBuffer->buffer + catBuffer->bufferUsedSz, buf, numBytesToCopy); catBuffer->bufferUsedSz += numBytesToCopy; if (catBuffer->bufferUsedSz < catBuffer->bufferAllocSz) { LOG_DEBUG ("conditional_access_section_read: catBuffer not yet full -- returning"); return 0; } b = bs_new(catBuffer->buffer, catBuffer->bufferUsedSz); } else { b = bs_new(buf, buf_len); } cas->table_id = bs_read_u8(b); if (cas->table_id != conditional_access_section) { LOG_ERROR_ARGS("Table ID in CAT is 0x%02X instead of expected 0x%02X", cas->table_id, conditional_access_section); reportAddErrorLogArgs("Table ID in CAT is 0x%02X instead of expected 0x%02X", cas->table_id, conditional_access_section); SAFE_REPORT_TS_ERR(-30); resetPSITableBuffer(catBuffer); bs_free (b); return 0; } // read byte 0 cas->section_syntax_indicator = bs_read_u1(b); if (!cas->section_syntax_indicator) { LOG_ERROR("section_syntax_indicator not set in CAT"); reportAddErrorLog("section_syntax_indicator not set in CAT"); SAFE_REPORT_TS_ERR(-31); resetPSITableBuffer(catBuffer); bs_free (b); return 0; } bs_skip_u(b, 3); // TODO read the zero bit, check it to be zero cas->section_length = bs_read_u(b, 12); if (cas->section_length > 1021) // max CAT length { LOG_ERROR_ARGS("CAT section length is 0x%02X, larger than maximum allowed 0x%02X", cas->section_length, MAX_SECTION_LEN); reportAddErrorLogArgs("CAT section length is 0x%02X, larger than maximum allowed 0x%02X", cas->section_length, MAX_SECTION_LEN); SAFE_REPORT_TS_ERR(-32); resetPSITableBuffer(catBuffer); bs_free (b); return 0; } if (cas->section_length > bs_bytes_left(b)) { LOG_DEBUG ("conditional_access_section_read: Detected section spans more than one TS packet -- allocating buffer"); if (catBuffer->buffer != NULL) { // should never get here LOG_ERROR ("conditional_access_section_read: unexpected catBufffer"); reportAddErrorLog ("conditional_access_section_read: unexpected catBufffer"); resetPSITableBuffer(catBuffer); } catBuffer->bufferAllocSz = cas->section_length + 3; catBuffer->buffer = (uint8_t *)calloc (cas->section_length + 3, 1); memcpy (catBuffer->buffer, buf, buf_len); catBuffer->bufferUsedSz = buf_len; bs_free (b); return 0; } // read bytes 1-2 bs_read_u16(b); // read bytes 3,4 bs_skip_u(b, 2); cas->version_number = bs_read_u(b, 5); cas->current_next_indicator = bs_read_u1(b); if (!cas->current_next_indicator) LOG_WARN("This CAT is not yet applicable/n"); // read byte 5 cas->section_number = bs_read_u8(b); cas->last_section_number = bs_read_u8(b); if (cas->section_number != 0 || cas->last_section_number != 0) LOG_WARN("Multi-section CAT is not supported yet/n"); // read bytes 6,7 read_descriptor_loop(cas->descriptors, b, cas->section_length - 5 - 4 ); // explanation: section_length gives us the length from the end of section_length // we used 5 bytes for the mandatory section fields, and will use another 4 bytes for CRC // the remaining bytes contain descriptors, most probably only one // again, it's much shorter in C :-) cas->CRC_32 = bs_read_u32(b); // check CRC crc_t cas_crc = crc_init(); cas_crc = crc_update(cas_crc, buf, bs_pos(b) - 4); cas_crc = crc_finalize(cas_crc); if (cas_crc != cas->CRC_32) { LOG_ERROR_ARGS("CAT CRC_32 specified as 0x%08X, but calculated as 0x%08X", cas->CRC_32, cas_crc); reportAddErrorLogArgs("CAT CRC_32 specified as 0x%08X, but calculated as 0x%08X", cas->CRC_32, cas_crc); SAFE_REPORT_TS_ERR(-33); resetPSITableBuffer(catBuffer); bs_free (b); return 0; } bs_free(b); resetPSITableBuffer(catBuffer); return 1; }
int program_association_section_read(program_association_section_t *pas, uint8_t *buf, size_t buf_len, uint32_t payload_unit_start_indicator, psi_table_buffer_t *patBuffer) { vqarray_t *programs; int num_programs = 0; if (pas == NULL || buf == NULL) { SAFE_REPORT_TS_ERR(-1); return 0; } bs_t *b = NULL; if (!payload_unit_start_indicator && patBuffer->buffer == NULL) { // this TS packet is not start of table, and we have no cached table data LOG_WARN ("program_association_section_read: payload_unit_start_indicator not set and no cached data"); return 0; } if (payload_unit_start_indicator) { uint8_t payloadStartPtr = buf[0]; buf += (payloadStartPtr + 1); buf_len -= (payloadStartPtr + 1); LOG_DEBUG_ARGS ("program_association_section_read: payloadStartPtr = %d", payloadStartPtr); } // check for pat spanning multiple TS packets if (patBuffer->buffer != NULL) { LOG_DEBUG_ARGS ("program_association_section_read: patBuffer detected: patBufferAllocSz = %d, patBufferUsedSz = %d", patBuffer->bufferAllocSz, patBuffer->bufferUsedSz); size_t numBytesToCopy = buf_len; if (buf_len > (patBuffer->bufferAllocSz - patBuffer->bufferUsedSz)) { numBytesToCopy = patBuffer->bufferAllocSz - patBuffer->bufferUsedSz; } LOG_DEBUG_ARGS ("program_association_section_read: copying %d bytes to patBuffer", numBytesToCopy); memcpy (patBuffer->buffer + patBuffer->bufferUsedSz, buf, numBytesToCopy); patBuffer->bufferUsedSz += numBytesToCopy; if (patBuffer->bufferUsedSz < patBuffer->bufferAllocSz) { LOG_DEBUG ("program_association_section_read: patBuffer not yet full -- returning"); return 0; } b = bs_new(patBuffer->buffer, patBuffer->bufferUsedSz); } else { b = bs_new(buf, buf_len); } pas->table_id = bs_read_u8(b); if (pas->table_id != program_association_section) { LOG_ERROR_ARGS("Table ID in PAT is 0x%02X instead of expected 0x%02X", pas->table_id, program_association_section); reportAddErrorLogArgs("Table ID in PAT is 0x%02X instead of expected 0x%02X", pas->table_id, program_association_section); SAFE_REPORT_TS_ERR(-30); resetPSITableBuffer(patBuffer); bs_free (b); return 0; } // read byte 0 pas->section_syntax_indicator = bs_read_u1(b); if (!pas->section_syntax_indicator) { LOG_ERROR("section_syntax_indicator not set in PAT"); reportAddErrorLog("section_syntax_indicator not set in PAT"); SAFE_REPORT_TS_ERR(-31); resetPSITableBuffer(patBuffer); bs_free (b); return 0; } bs_skip_u(b, 3); // TODO read the zero bit, check it to be zero pas->section_length = bs_read_u(b, 12); if (pas->section_length > MAX_SECTION_LEN) { LOG_ERROR_ARGS("PAT section length is 0x%02X, larger than maximum allowed 0x%02X", pas->section_length, MAX_SECTION_LEN); reportAddErrorLogArgs("PAT section length is 0x%02X, larger than maximum allowed 0x%02X", pas->section_length, MAX_SECTION_LEN); SAFE_REPORT_TS_ERR(-32); resetPSITableBuffer(patBuffer); bs_free (b); return 0; } if (pas->section_length > bs_bytes_left(b)) { LOG_DEBUG ("program_association_section_read: Detected section spans more than one TS packet -- allocating buffer"); if (patBuffer->buffer != NULL) { // should never get here LOG_ERROR ("program_association_section_read: unexpected patBufffer"); reportAddErrorLog ("program_association_section_read: unexpected patBufffer"); resetPSITableBuffer(patBuffer); } patBuffer->bufferAllocSz = pas->section_length + 3; patBuffer->buffer = (uint8_t *)calloc (pas->section_length + 3, 1); memcpy (patBuffer->buffer, buf, buf_len); patBuffer->bufferUsedSz = buf_len; bs_free (b); return 0; } // read bytes 1,2 pas->transport_stream_id = bs_read_u16(b); // read bytes 3,4 bs_skip_u(b, 2); pas->version_number = bs_read_u(b, 5); pas->current_next_indicator = bs_read_u1(b); if (!pas->current_next_indicator) LOG_WARN("This PAT is not yet applicable/n"); // read byte 5 pas->section_number = bs_read_u8(b); pas->last_section_number = bs_read_u8(b); if (pas->section_number != 0 || pas->last_section_number != 0) LOG_WARN("Multi-section PAT is not supported yet/n"); // read bytes 6,7 num_programs = (pas->section_length - 5 - 4) / 4; // Programs listed in the PAT // explanation: section_length gives us the length from the end of section_length // we used 5 bytes for the mandatory section fields, and will use another 4 bytes for CRC // the remaining bytes contain program information, which is 4 bytes per iteration // It's much shorter in C :-) // Read the program loop, but ignore the NIT PID "program" programs = vqarray_new(); for (uint32_t i = 0; i < num_programs; i++) { program_info_t *prog = malloc(sizeof(program_info_t)); prog->program_number = bs_read_u16(b); if (prog->program_number == 0) { // Skip the NIT PID program (not a real program) free(prog); bs_skip_u(b, 16); continue; } bs_skip_u(b, 3); prog->program_map_PID = bs_read_u(b, 13); vqarray_add(programs, (vqarray_elem_t*)prog); } // This is our true number of programs pas->_num_programs = vqarray_length(programs); if (pas->_num_programs > 1) LOG_WARN_ARGS("%zd programs found, but only SPTS is fully supported. Patches are welcome.", pas->_num_programs); // Copy form our vqarray into the native array pas->programs = malloc(pas->_num_programs * sizeof(program_info_t)); for (uint32_t i = 0; i < pas->_num_programs; i++) { program_info_t* prog = (program_info_t*)vqarray_pop(programs); pas->programs[i] = *prog; free(prog); } vqarray_free(programs); pas->CRC_32 = bs_read_u32(b); // check CRC crc_t pas_crc = crc_init(); pas_crc = crc_update(pas_crc, buf, bs_pos(b) - 4); pas_crc = crc_finalize(pas_crc); if (pas_crc != pas->CRC_32) { LOG_ERROR_ARGS("PAT CRC_32 specified as 0x%08X, but calculated as 0x%08X", pas->CRC_32, pas_crc); reportAddErrorLogArgs("PAT CRC_32 specified as 0x%08X, but calculated as 0x%08X", pas->CRC_32, pas_crc); SAFE_REPORT_TS_ERR(-33); resetPSITableBuffer(patBuffer); bs_free (b); return 0; } else { // LOG_DEBUG("PAT CRC_32 checked successfully"); // don't enable unless you want to see this every ~100ms } bs_free(b); resetPSITableBuffer(patBuffer); return 1; }
int program_map_section_read(program_map_section_t *pms, uint8_t *buf, size_t buf_size, uint32_t payload_unit_start_indicator, psi_table_buffer_t *pmtBuffer) { LOG_DEBUG ("program_map_section_read -- entering"); if (pms == NULL || buf == NULL) { SAFE_REPORT_TS_ERR(-1); return 0; } bs_t *b = NULL; if (!payload_unit_start_indicator && pmtBuffer->buffer == NULL) { // this TS packet is not start of table, and we have no cached table data LOG_WARN ("program_map_section_read: payload_unit_start_indicator not set and no cached data"); return 0; } if (payload_unit_start_indicator) { uint8_t payloadStartPtr = buf[0]; buf += (payloadStartPtr + 1); buf_size -= (payloadStartPtr + 1); LOG_DEBUG_ARGS ("program_map_section_read: payloadStartPtr = %d", payloadStartPtr); } // check for pmt spanning multiple TS packets if (pmtBuffer->buffer != NULL) { LOG_DEBUG_ARGS ("program_map_section_read: pmtBuffer detected: pmtBufferAllocSz = %d, pmtBufferUsedSz = %d", pmtBuffer->bufferAllocSz, pmtBuffer->bufferUsedSz); size_t numBytesToCopy = buf_size; if (buf_size > (pmtBuffer->bufferAllocSz - pmtBuffer->bufferUsedSz)) { numBytesToCopy = pmtBuffer->bufferAllocSz - pmtBuffer->bufferUsedSz; } LOG_DEBUG_ARGS ("program_map_section_read: copying %d bytes to pmtBuffer", numBytesToCopy); memcpy (pmtBuffer->buffer + pmtBuffer->bufferUsedSz, buf, numBytesToCopy); pmtBuffer->bufferUsedSz += numBytesToCopy; if (pmtBuffer->bufferUsedSz < pmtBuffer->bufferAllocSz) { LOG_DEBUG ("program_map_section_read: pmtBuffer not yet full -- returning"); return 0; } b = bs_new(pmtBuffer->buffer, pmtBuffer->bufferUsedSz); } else { b = bs_new(buf, buf_size); } pms->table_id = bs_read_u8(b); if (pms->table_id != TS_program_map_section) { LOG_ERROR_ARGS("Table ID in PMT is 0x%02X instead of expected 0x%02X", pms->table_id, TS_program_map_section); reportAddErrorLogArgs("Table ID in PMT is 0x%02X instead of expected 0x%02X", pms->table_id, TS_program_map_section); SAFE_REPORT_TS_ERR(-40); resetPSITableBuffer(pmtBuffer); bs_free (b); return 0; } pms->section_syntax_indicator = bs_read_u1(b); if (!pms->section_syntax_indicator) { LOG_ERROR("section_syntax_indicator not set in PMT"); reportAddErrorLog("section_syntax_indicator not set in PMT"); SAFE_REPORT_TS_ERR(-41); resetPSITableBuffer(pmtBuffer); bs_free (b); return 0; } bs_skip_u(b, 3); pms->section_length = bs_read_u(b, 12); if (pms->section_length > MAX_SECTION_LEN) { LOG_ERROR_ARGS("PMT section length is 0x%02X, larger than maximum allowed 0x%02X", pms->section_length, MAX_SECTION_LEN); reportAddErrorLogArgs("PMT section length is 0x%02X, larger than maximum allowed 0x%02X", pms->section_length, MAX_SECTION_LEN); SAFE_REPORT_TS_ERR(-42); resetPSITableBuffer(pmtBuffer); bs_free (b); return 0; } if (pms->section_length > bs_bytes_left(b)) { LOG_DEBUG ("program_map_section_read: Detected section spans more than one TS packet -- allocating buffer"); if (pmtBuffer->buffer != NULL) { // should never get here LOG_ERROR ("program_map_section_read: unexpected pmtBufffer"); reportAddErrorLog ("program_map_section_read: unexpected pmtBufffer"); resetPSITableBuffer(pmtBuffer); } pmtBuffer->bufferAllocSz = pms->section_length + 3; pmtBuffer->buffer = (uint8_t *)calloc (pms->section_length + 3, 1); memcpy (pmtBuffer->buffer, buf, buf_size); pmtBuffer->bufferUsedSz = buf_size; bs_free (b); return 0; } int section_start = bs_pos(b); // bytes 0,1 pms->program_number = bs_read_u16(b); // byte 2; bs_skip_u(b, 2); pms->version_number = bs_read_u(b, 5); pms->current_next_indicator = bs_read_u1(b); if (!pms->current_next_indicator) LOG_WARN("This PMT is not yet applicable/n"); // bytes 3,4 pms->section_number = bs_read_u8(b); pms->last_section_number = bs_read_u8(b); if (pms->section_number != 0 || pms->last_section_number != 0) { LOG_ERROR("Multi-section PMT is not allowed/n"); reportAddErrorLog("Multi-section PMT is not allowed/n"); SAFE_REPORT_TS_ERR(-43); resetPSITableBuffer(pmtBuffer); bs_free (b); return 0; } bs_skip_u(b, 3); pms->PCR_PID = bs_read_u(b, 13); if (pms->PCR_PID < GENERAL_PURPOSE_PID_MIN || pms->PCR_PID > GENERAL_PURPOSE_PID_MAX) { LOG_ERROR_ARGS("PCR PID has invalid value 0x%02X", pms->PCR_PID); reportAddErrorLogArgs("PCR PID has invalid value 0x%02X", pms->PCR_PID); SAFE_REPORT_TS_ERR(-44); resetPSITableBuffer(pmtBuffer); bs_free (b); return 0; } // printf ("PCR PID = %d\n", pms->PCR_PID); bs_skip_u(b, 4); pms->program_info_length = bs_read_u(b, 12); if (pms->program_info_length > MAX_PROGRAM_INFO_LEN) { LOG_ERROR_ARGS("PMT program info length is 0x%02X, larger than maximum allowed 0x%02X", pms->program_info_length, MAX_PROGRAM_INFO_LEN); reportAddErrorLogArgs("PMT program info length is 0x%02X, larger than maximum allowed 0x%02X", pms->program_info_length, MAX_PROGRAM_INFO_LEN); SAFE_REPORT_TS_ERR(-45); resetPSITableBuffer(pmtBuffer); bs_free (b); return 0; } read_descriptor_loop(pms->descriptors, b, pms->program_info_length); while (!bs_eof(b) && pms->section_length - (bs_pos(b) - section_start) > 4) // account for CRC { elementary_stream_info_t *es = es_info_new(); es_info_read(es, b); vqarray_add(pms->es_info, es); } pms->CRC_32 = bs_read_u32(b); // check CRC crc_t pas_crc = crc_init(); pas_crc = crc_update(pas_crc, b->start, bs_pos(b) - 4); pas_crc = crc_finalize(pas_crc); if (pas_crc != pms->CRC_32) { LOG_ERROR_ARGS("PMT CRC_32 specified as 0x%08X, but calculated as 0x%08X", pms->CRC_32, pas_crc); reportAddErrorLogArgs("PMT CRC_32 specified as 0x%08X, but calculated as 0x%08X", pms->CRC_32, pas_crc); SAFE_REPORT_TS_ERR(-46); resetPSITableBuffer(pmtBuffer); bs_free (b); return 0; } else { // LOG_DEBUG("PMT CRC_32 checked successfully"); } int bytes_read = bs_pos(b); bs_free(b); resetPSITableBuffer(pmtBuffer); return bytes_read; }
int pes_read_header(pes_header_t *ph, bs_t *b) { int PES_packet_start = bs_pos(b); // we *really* care about bytes 0..19, as we can cheat and manipulate PTS/DTS this way if (bs_bytes_left(b) < 20) return 0; // bytes 0..2 uint32_t pes_packet_start_code = bs_read_u24(b); if (pes_packet_start_code != PES_PACKET_START_CODE_PREFIX) { int actually_read = bs_pos(b) - PES_packet_start; b->p -= actually_read; // undo the read LOG_WARN_ARGS("PES packet starts with 0x%06X instead of expected start code 0x%06X, skipping it", pes_packet_start_code, PES_PACKET_START_CODE_PREFIX); return 0; // bail out! something is fishy! } // bytes 3..5 ph->stream_id = bs_read_u8(b); ph->PES_packet_length = bs_read_u16(b); if (HAS_PES_HEADER(ph->stream_id)) { // byte 6 bs_skip_u(b, 2); ph->PES_scrambling_control = bs_read_u(b, 2); ph->PES_priority = bs_read_u1(b); ph->data_alignment_indicator = bs_read_u1(b); ph->copyright = bs_read_u1(b); ph->original_or_copy = bs_read_u1(b); // byte 7 ph->PTS_DTS_flags = bs_read_u(b, 2); ph->ESCR_flag = bs_read_u1(b); ph->ES_rate_flag = bs_read_u1(b); ph->DSM_trick_mode_flag = bs_read_u1(b); ph->additional_copy_info_flag = bs_read_u1(b); ph->PES_CRC_flag = bs_read_u1(b); ph->PES_extension_flag = bs_read_u1(b); // byte 8 ph->PES_header_data_length = bs_read_u8(b); int PES_packet_optional_start = bs_pos(b); // byte 9..14 if (ph->PTS_DTS_flags & PES_PTS_FLAG) { bs_skip_u(b, 4); ph->PTS = bs_read_90khz_timestamp(b); } // byte 15..19 if (ph->PTS_DTS_flags & PES_DTS_FLAG) { bs_skip_u(b, 4); ph->DTS = bs_read_90khz_timestamp(b); } if (ph->ESCR_flag) { bs_skip_u(b, 2); ph->ESCR_base = bs_read_90khz_timestamp(b); ph->ESCR_extension = bs_read_u(b, 9); bs_skip_u1(b); } if (ph->ES_rate_flag) { bs_skip_u1(b); ph->ES_rate = bs_read_u(b, 22); bs_skip_u1(b); } if (ph->DSM_trick_mode_flag) { ph->trick_mode_control = bs_read_u(b, 3); switch (ph->trick_mode_control) { case PES_DSM_TRICK_MODE_CTL_FAST_FORWARD: case PES_DSM_TRICK_MODE_CTL_FAST_REVERSE: ph->field_id = bs_read_u(b, 2); ph->intra_slice_refresh = bs_read_u1(b); ph->frequency_truncation = bs_read_u(b, 2); break; case PES_DSM_TRICK_MODE_CTL_SLOW_MOTION: case PES_DSM_TRICK_MODE_CTL_SLOW_REVERSE: ph->rep_cntrl = bs_read_u(b, 5); break; case PES_DSM_TRICK_MODE_CTL_FREEZE_FRAME: ph->field_id = bs_read_u(b, 2); bs_skip_u(b, 3); break; default: bs_skip_u(b, 5); break; } } if (ph->additional_copy_info_flag) { bs_skip_u1(b); ph->additional_copy_info = bs_read_u(b, 7); } if (ph->PES_CRC_flag) { ph->previous_PES_packet_CRC = bs_read_u16(b); } if (ph->PES_extension_flag) { ph->PES_private_data_flag = bs_read_u1(b); ph->pack_header_field_flag = bs_read_u1(b); ph->program_packet_sequence_counter_flag = bs_read_u1(b); ph->PSTD_buffer_flag = bs_read_u1(b); bs_skip_u(b, 3); ph->PES_extension_flag_2 = bs_read_u1(b); if (ph->PES_private_data_flag) bs_read_bytes(b, ph->PES_private_data, 16); if (ph->pack_header_field_flag) { // whoever discovers the need for pack_header() is welcome to implement it. // I haven't. ph->pack_field_length = bs_read_u8(b); bs_skip_bytes(b, ph->pack_field_length); } if (ph->program_packet_sequence_counter_flag) { bs_skip_u1(b); ph->program_packet_sequence_counter = bs_read_u(b, 7); bs_skip_u1(b); ph->MPEG1_MPEG2_identifier = bs_read_u1(b); ph->original_stuff_length = bs_read_u(b, 6); } if (ph->PSTD_buffer_flag) { bs_skip_u(b, 2); ph->PSTD_buffer_scale = bs_read_u1(b); ph->PSTD_buffer_size = bs_read_u(b, 13); } if (ph->PES_extension_flag_2) { int PES_extension_field_start = bs_pos(b); bs_skip_u1(b); ph->PES_extension_field_length = bs_read_u(b, 7); ph->stream_id_extension_flag = bs_read_u1(b); if (!ph->stream_id_extension_flag) { ph->stream_id_extension = bs_read_u(b, 7); } else { bs_skip_u(b, 6); ph->tref_extension_flag = bs_read_u1(b); if (ph->tref_extension_flag) { bs_skip_u(b, 4); ph->TREF = bs_read_90khz_timestamp(b); } } int PES_extension_bytes_left = bs_pos(b) - PES_extension_field_start; if (PES_extension_bytes_left > 0) bs_skip_bytes(b, PES_extension_bytes_left); } } int PES_optional_bytes_read = bs_pos(b) - PES_packet_optional_start; int stuffing_bytes_len = ph->PES_header_data_length - PES_optional_bytes_read; // if any if (stuffing_bytes_len > 0) bs_skip_bytes(b, stuffing_bytes_len); } return (bs_pos(b) - PES_packet_start); }