parsePat = function(payload, pat) {
pat.section_number = payload[7]; // eslint-disable-line camelcase
pat.last_section_number = payload[8]; // eslint-disable-line camelcase

// skip the PSI header and parse the first PMT entry
self.pmtPid = (payload[10] & 0x1F) << 8 | payload[11];
pat.pmtPid = self.pmtPid;

};

i check ISO_IEC_13818-1 2.4.4.3
the section_number should be payload[6], last_section_number is payload[7]
while program_map_PID is part of payload[10] and payload[11] .

program_association_section() {
table_id 8 uimsbf
section_syntax_indicator 1 bslbf
'0' 1 bslbf
reserved 2 bslbf
section_length 12 uimsbf
transport_stream_id 16 uimsbf
reserved 2 bslbf
version_number 5 uimsbf
current_next_indicator 1 bslbf
section_number 8 uimsbf
last_section_number 8 uimsbf
for (i = 0; i < N; i++) {
program_number 16 uimsbf
reserved 3 bslbf
if (program_number = = '0') {
network_PID 13 uimsbf
} else {
program_map_PID 13 uimsbf
}
}
CRC_32 32 rpchof
}