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main.js
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main.js
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const file = document.querySelector('#file');
file.addEventListener('change', (e) => {
const fileReader = new FileReader();
if (e.target.files) {
const file = e.target.files[0];
fileReader.addEventListener('load', () => {
parse(fileReader.result);
});
fileReader.readAsArrayBuffer(file);
}
});
const getCentiTime = (clock) => {
const K = 27000; // Hz
return clock / (K / 100);
};
/**
*
* @param {ArrayBuffer} data
*/
function parse(data) {
let no = 0;
let pmtTable = null;
let pcrPid = null;
let captionPid = null;
let buffer = new Uint8Array(data.slice(no * 188, no * 188 + 188));
let clock;
while (buffer.byteLength === 188) {
buffer = new Uint8Array(data.slice(no * 188, no * 188 + 188));
if (buffer[0] !== 0x47) {
console.log('Not a valid ts packet');
}
// tei
const isError = buffer[1] & 0x80;
const payloadUnitStartIndicator = Boolean(buffer[1] & 0x40);
const pid = ((buffer[1] & 0x1f) << 8) + buffer[2];
const adaptationControl = (buffer[3] & 0x30) >> 4;
const hasPayload = Boolean(adaptationControl & 0b01);
const hasAdaption = Boolean(adaptationControl & 0b10);
const continutity = buffer[3] & 0x0f;
let idx = 4;
let offset = 0;
if (hasAdaption) {
const adaptationFieldLength = buffer[idx];
idx += 1;
const pcrFlag = Boolean((buffer[idx] & 0x10) >> 4);
if (pcrFlag && pid === pcrPid) {
// PCR = 42bit
// = PCR-base (33bit) + PCR-ext (9bit)
const pcrBase =
(buffer[idx + 1] << 25) +
(buffer[idx + 2] << 17) +
(buffer[idx + 3] << 9) +
(buffer[idx + 4] << 1) +
((buffer[idx + 5] & 0x80) >> 7);
const pcrExt = (buffer[idx + 5] & 0x01) + buffer[idx + 6];
clock = BigInt(pcrBase * 300 + pcrExt);
}
idx += adaptationFieldLength;
}
if (hasPayload) {
if (!pmtTable && pid === 0) {
const d = buffer.slice(idx + 1);
pmtTable = parsePAT(d);
} else if (
!captionPid &&
pmtTable &&
Array.from(pmtTable.values()).includes(pid)
) {
if (payloadUnitStartIndicator) {
const d = buffer.slice(idx + 1);
pcrPid = parsePCRPid(d);
captionPid = parseCaptionPid(d);
}
} else if (pid === 0x0014) {
// TODO: Time offset table
const currentTime = parseTimeTable(buffer.slice(idx + 1));
if (currentTime) {
}
} else if (pid === captionPid) {
if (payloadUnitStartIndicator) {
parseCaption(buffer.slice(idx));
}
}
}
no += 1;
}
}
function parseTimeTable(data) {
// byte1 + byte2
const tableId = data[0];
const mjd = (data[3] << 8) + data[4];
// TODO: I think the implementation was wrong but date is correct...
const Y_ = Math.floor((mjd - 15078.2) / 365.25);
const M_ = 12 - Math.floor((mjd - 14856.1 - Y_ * 365.25) / 30.6001);
const D_ =
mjd - 14956.1 - Math.floor(Y_ * 365.25) - Math.floor(M_ * 30.6001) - 30;
let K = 0;
if (M_ === 14 || M_ === 15) {
K = 1;
}
const year = Y_ + K + 1900;
const month = M_ - K * 12;
const date = D_;
const hour = (data[5] >> 4) * 10 + (data[5] & 0x0f);
const min = (data[6] >> 4) * 10 + (data[6] & 0x0f);
const sec = (data[7] >> 4) * 10 + (data[7] & 0x0f);
return new Date(
`${year}/${month + 1}/${Math.floor(date)} ${hour}:${min}:${sec}`
);
}
function parseCaption(data) {
const startCodePrefix = (data[0] << 16) + (data[1] << 8) + data[2];
const streamId = data[3];
const pesPacketLength = (data[4] << 8) + data[5];
const pesHeaderDataLength = data[8];
// =========
// werid?
const pesDataPacketHeaderLength = data[11 + pesHeaderDataLength] & 0x0f;
let offset = 12 + pesHeaderDataLength + pesDataPacketHeaderLength;
let d = data.slice(offset);
// TODO: spec
// http://www.arib.or.jp/english/html/overview/doc/6-STD-B24v6_4-1p3-E1.pdf
const dataGroupId = (d[0] & 0xfc) >> 2;
const dataGroupVersion = d[0] & 0x03;
const dataGroupLinkNumber = d[1];
if (dataGroupId === 0x20 || dataGroupId === 0x00) {
const numLanguages = d[6];
console.log('lan', numLanguages);
offset += 7 + numLanguages * 5;
} else {
console.log('data group id:', dataGroupId.toString('16'));
offset += 6;
}
d = data.slice(offset);
const dataUnitLoopLength = (d[0] << 16) + (d[1] << 8) + d[2];
let idx = 0;
while (idx < dataUnitLoopLength) {
const separator = d[idx + 3];
const dataUnitParameter = d[idx + 4];
const dataUnitSize = (d[idx + 5] << 16) + (d[idx + 6] << 8) + d[idx + 7];
// 0x20 - statement body
// 0x28 - geometric
// 0x30 - 1-byte DRCS
// 0x31 - 2-byte DRCS
// 0x34 - Color map
// 0x35 - Bitmap
if (dataUnitParameter === 0x20) {
parseText(d.slice(5), dataUnitSize);
} else if (dataUnitParameter === 0x30) {
console.log('[TODO] 1-byte DRCS');
} else if (dataUnitParameter === 0x31) {
console.log('[TODO] 2-byte DRCS');
} else if (dataUnitParameter === 0x34) {
console.log('[TODO] Color map');
} else if (dataUnitParameter === 0x35) {
console.log('[TODO] Bitmap');
}
idx += 5 + dataUnitSize;
}
}
function parseText(data, length) {
// TODO: have to handle a lot of case
const str = data.slice(0, length + 1);
let result = '';
let i = 0;
while (i < length) {
if (str[i] === 0x20) {
result += ' ';
i += 1;
}
// // JIS X 0208 (lead bytes)
if (str[i] > 0xa0 && str[i] < 0xff) {
const char = str.slice(i, i + 2);
if (str[i] >= 0xfa) {
result += parseGaiji(char);
i += 2;
} else {
const decoded = new TextDecoder('EUC-JP').decode(char);
result += decoded;
i += 2;
}
} else if (Object.values(JIS_CONTROL_FUNCTION_TABLE).includes(str[i])) {
console.log('JIS_CONTROL_TABLE!');
i += 1;
} else if (str[i] >= 0x80 && str[i] <= 0x87) {
console.log('color map');
i += 1;
} else {
i += 1;
}
}
console.log(result);
document.querySelector('#result').innerHTML += result + '<br/>';
}
function parseGaiji(data) {
// offset is 0xa0
console.log('Parse Gaiji:');
printInByte(data);
const row = data[0] - 0xa0;
const cell = data[1] - 0xa0;
return JIS_GAIJI[row.toString()][cell.toString()];
}
function parseCaptionPid(data) {
const tableId = data[0];
if (tableId !== 0x02) {
console.log('not caption table');
}
const sectionLength = ((data[1] & 0x0f) << 8) + data[2];
const programInfoLength = ((data[10] & 0x0f) << 8) + data[11];
let idx = 12 + programInfoLength;
// TODO: remove magic number
while (idx < 3 + sectionLength - 4) {
const streamType = data[idx];
const elementaryPid = ((data[idx + 1] & 0x1f) << 8) + data[idx + 2];
const ESInfoLength = ((data[idx + 3] & 0x0f) << 8) + data[idx + 4];
// MPEG-2 PES Private data
if (streamType === 0x06) {
let descriptorIdx = idx + 5;
const descriptorData = data.slice(descriptorIdx);
while (descriptorIdx < idx + ESInfoLength) {
const descriptorTag = descriptorData[0];
const descriptorLength = descriptorData[1];
console.log(descriptorTag, descriptorLength);
// TODO: descriptor tag spec explaination
if (descriptorTag === 0x52) {
console.log('stream identifier descriptor');
const componentTag = descriptorData[2];
console.log('tag:', componentTag);
if (componentTag === 0x87) {
return elementaryPid;
}
}
descriptorIdx += 2 + descriptorLength;
}
}
idx += 5 + ESInfoLength;
}
}
// PMT table
function parsePCRPid(data) {
return ((data[8] & 0x1f) << 8) + data[9];
}
function parsePAT(data) {
const tableId = data[0];
if (tableId !== 0x00) {
// TODO
}
const sectionLength = ((data[1] & 0x0f) << 8) + data[2];
const idx = 8;
let i = idx;
const pat = new Map();
while (i < 3 + sectionLength - 4) {
const programNumber = (data[i] << 8) + data[i + 1];
if (programNumber !== 0) {
const programMapPid = ((data[i + 2] & 0x1f) << 8) + data[i + 3];
pat.set(programNumber, programMapPid);
}
i += 4;
}
console.log(pat);
return pat;
}
function printInByte(buffer) {
let str = '';
buffer.forEach((num, i) => {
str += num.toString('16').toUpperCase().padStart(2, '0') + ' ';
if (i % 16 === 15) {
str += '\n';
}
});
console.log(str);
}