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audio-player: corrected indentation and comments

This commit is contained in:
Trek H 2019-09-24 17:15:58 +09:30
parent 1a8493853e
commit 1de5438565
4 changed files with 142 additions and 140 deletions
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148
cmd/audio-player/adpcm.js
View File

@ -29,24 +29,24 @@ LICENSE
// Table of index changes (see spec). // Table of index changes (see spec).
const indexTable = [ const indexTable = [
-1, -1, -1, -1, 2, 4, 6, 8, -1, -1, -1, -1, 2, 4, 6, 8,
-1, -1, -1, -1, 2, 4, 6, 8 -1, -1, -1, -1, 2, 4, 6, 8
]; ];
// Quantize step size table (see spec). // Quantize step size table (see spec).
const stepTable = [ const stepTable = [
7, 8, 9, 10, 11, 12, 13, 14, 7, 8, 9, 10, 11, 12, 13, 14,
16, 17, 19, 21, 23, 25, 28, 31, 16, 17, 19, 21, 23, 25, 28, 31,
34, 37, 41, 45, 50, 55, 60, 66, 34, 37, 41, 45, 50, 55, 60, 66,
73, 80, 88, 97, 107, 118, 130, 143, 73, 80, 88, 97, 107, 118, 130, 143,
157, 173, 190, 209, 230, 253, 279, 307, 157, 173, 190, 209, 230, 253, 279, 307,
337, 371, 408, 449, 494, 544, 598, 658, 337, 371, 408, 449, 494, 544, 598, 658,
724, 796, 876, 963, 1060, 1166, 1282, 1411, 724, 796, 876, 963, 1060, 1166, 1282, 1411,
1552, 1707, 1878, 2066, 2272, 2499, 2749, 3024, 1552, 1707, 1878, 2066, 2272, 2499, 2749, 3024,
3327, 3660, 4026, 4428, 4871, 5358, 5894, 6484, 3327, 3660, 4026, 4428, 4871, 5358, 5894, 6484,
7132, 7845, 8630, 9493, 10442, 11487, 12635, 13899, 7132, 7845, 8630, 9493, 10442, 11487, 12635, 13899,
15289, 16818, 18500, 20350, 22385, 24623, 27086, 29794, 15289, 16818, 18500, 20350, 22385, 24623, 27086, 29794,
32767 32767
]; ];
const byteDepth = 2; // We are working with 16-bit samples. TODO(Trek): make configurable. const byteDepth = 2; // We are working with 16-bit samples. TODO(Trek): make configurable.
@ -59,89 +59,89 @@ let step = 0;
// decodeSample takes 4 bits which represents a single ADPCM nibble, and returns a 16 bit decoded PCM sample. // decodeSample takes 4 bits which represents a single ADPCM nibble, and returns a 16 bit decoded PCM sample.
function decodeSample(nibble) { function decodeSample(nibble) {
let diff = 0; let diff = 0;
if ((nibble & 4) != 0) { if ((nibble & 4) != 0) {
diff += step; diff += step;
} }
if ((nibble & 2) != 0) { if ((nibble & 2) != 0) {
diff += step >> 1; diff += step >> 1;
} }
if ((nibble & 1) != 0) { if ((nibble & 1) != 0) {
diff += step >> 2; diff += step >> 2;
} }
diff += step >> 3; diff += step >> 3;
if ((nibble & 8) != 0) { if ((nibble & 8) != 0) {
diff = -diff; diff = -diff;
} }
est += diff; est += diff;
idx += indexTable[nibble]; idx += indexTable[nibble];
if (idx < 0) { if (idx < 0) {
idx = 0; idx = 0;
} else if (idx > stepTable.length - 1) { } else if (idx > stepTable.length - 1) {
idx = stepTable.length - 1; idx = stepTable.length - 1;
} }
step = stepTable[idx]; step = stepTable[idx];
result = est; result = est;
return result; return result;
} }
// decode takes an array of bytes of arbitrary length representing adpcm and decodes it into pcm. // decode takes an array of bytes of arbitrary length representing adpcm and decodes it into pcm.
function decode(b) { function decode(b) {
// Iterate over each chunk and decode it. // Iterate over each chunk and decode it.
let chunkLen; let chunkLen;
var result = []; var result = [];
for (var off = 0; off + headSize <= b.length; off += chunkLen) { for (var off = 0; off + headSize <= b.length; off += chunkLen) {
// Read length of chunk and check if whole chunk exists. // Read length of chunk and check if whole chunk exists.
chunkLen = bytesToInt32(b.slice(off, off + chunkLenSize)) chunkLen = bytesToInt32(b.slice(off, off + chunkLenSize))
if (off + chunkLen > b.length) { if (off + chunkLen > b.length) {
break; break;
} }
// Initialize Decoder with first 4 bytes of b. // Initialize Decoder with first 4 bytes of b.
est = bytesToInt16(b.slice(off + chunkLenSize, off + chunkLenSize + byteDepth)); est = bytesToInt16(b.slice(off + chunkLenSize, off + chunkLenSize + byteDepth));
idx = b[off + chunkLenSize + byteDepth]; idx = b[off + chunkLenSize + byteDepth];
step = stepTable[idx]; step = stepTable[idx];
result.push(...b.slice(off + chunkLenSize, off + chunkLenSize + byteDepth)); result.push(...b.slice(off + chunkLenSize, off + chunkLenSize + byteDepth));
for (var i = off + headSize; i < off + chunkLen - b[off + chunkLenSize + 3]; i++) { for (var i = off + headSize; i < off + chunkLen - b[off + chunkLenSize + 3]; i++) {
var twoNibs = b[i]; var twoNibs = b[i];
var nib2 = twoNibs >> 4; var nib2 = twoNibs >> 4;
var nib1 = (nib2 << 4) ^ twoNibs; var nib1 = (nib2 << 4) ^ twoNibs;
var sample1 = int16ToBytes(decodeSample(nib1)); var sample1 = int16ToBytes(decodeSample(nib1));
result.push(...sample1); result.push(...sample1);
var sample2 = int16ToBytes(decodeSample(nib2)); var sample2 = int16ToBytes(decodeSample(nib2));
result.push(...sample2); result.push(...sample2);
} }
if (b[off + chunkLenSize + 3] == 1) { if (b[off + chunkLenSize + 3] == 1) {
var padNib = b[off + chunkLen - 1]; var padNib = b[off + chunkLen - 1];
var sample = int16ToBytes(decodeSample(padNib)); var sample = int16ToBytes(decodeSample(padNib));
result.push(...sample); result.push(...sample);
} }
} }
return result; return result;
} }
// int16ToBytes takes a number assumed to be an int 16 and converts it to an array containing bytes (Little Endian). // int16ToBytes takes a number assumed to be an int 16 and converts it to an array containing bytes (Little Endian).
function int16ToBytes(num) { function int16ToBytes(num) {
return [(num & 0x00ff), (num & 0xff00) >> 8]; return [(num & 0x00ff), (num & 0xff00) >> 8];
} }
// bytesToInt16 takes an array of bytes (assumed to be values between 0 and 255), interprates them as little endian and converts it to an int16. // bytesToInt16 takes an array of bytes (assumed to be values between 0 and 255), interprates them as little endian and converts it to an int16.
function bytesToInt16(b) { function bytesToInt16(b) {
return (b[0] | (b[1] << 8)); return (b[0] | (b[1] << 8));
} }
// bytesToInt32 takes an array of bytes (assumed to be values between 0 and 255), interprates them as little endian and converts it to an int32. // bytesToInt32 takes an array of bytes (assumed to be values between 0 and 255), interprates them as little endian and converts it to an int32.
function bytesToInt32(b) { function bytesToInt32(b) {
return (b[0] | return (b[0] |
(b[1] << 8) | (b[1] << 8) |
(b[2] << 16) | (b[2] << 16) |
(b[3] << 24)); (b[3] << 24));
} }

2
cmd/audio-player/index.html
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@ -23,7 +23,7 @@
</div> </div>
<div class="container-fluid"> <div class="container-fluid">
<div class="form-group"> <div class="form-group">
<input class="form-control-file" type="file" id="fileinput" onchange="processData();"> <input class="form-control-file" type="file" id="fileinput" onchange="playFile();">
</div> </div>
</div> </div>
<div class="container-fluid"> <div class="container-fluid">

120
cmd/audio-player/main.js
View File

@ -23,82 +23,84 @@ LICENSE
If not, see [GNU licenses](http://www.gnu.org/licenses). If not, see [GNU licenses](http://www.gnu.org/licenses).
*/ */
function processData() { // playFile will process and play the chosen target file.
const input = event.target.files[0] function playFile() {
const reader = new FileReader() const input = event.target.files[0]
const reader = new FileReader()
reader.onload = event => { reader.onload = event => {
bytes = new Uint8Array(event.target.result) bytes = new Uint8Array(event.target.result)
// decode adpcm to pcm // Decode adpcm to pcm.
var decoded = decode(Array.from(bytes)) var decoded = decode(Array.from(bytes))
// convert raw pcm to wav TODO(Trek): make these configurable. // Convert raw pcm to wav TODO(Trek): make these configurable.
var wav = pcmToWav(decoded, 48000, 1, 16); var wav = pcmToWav(decoded, 48000, 1, 16);
// play wav data in player // Play wav data in player.
const blob = new Blob([Uint8Array.from(wav)], { const blob = new Blob([Uint8Array.from(wav)], {
type: 'audio/wav' type: 'audio/wav'
}); });
const url = URL.createObjectURL(blob); const url = URL.createObjectURL(blob);
const audio = document.getElementById('audio'); const audio = document.getElementById('audio');
const source = document.getElementById('source'); const source = document.getElementById('source');
source.src = url; source.src = url;
audio.load(); audio.load();
audio.play(); audio.play();
} }
reader.onerror = error => reject(error) reader.onerror = error => reject(error)
reader.readAsArrayBuffer(input) reader.readAsArrayBuffer(input)
} }
// getQuery gets everything after the question mark in the URL. // getQuery gets everything after the question mark in the URL.
function getQuery() { function getQuery() {
var regex = new RegExp("\\?(.*)"); var regex = new RegExp("\\?(.*)");
var match = regex.exec(window.location.href); var match = regex.exec(window.location.href);
if (match == null) { if (match == null) {
return ''; return '';
} else { } else {
return decodeURIComponent(match[1].replace(/\+/g, " ")); return decodeURIComponent(match[1].replace(/\+/g, " "));
} }
} }
// load gets the file from the given url and displays a link for download.
function load() { function load() {
var url = document.getElementById('url').value; var url = document.getElementById('url').value;
if (url == "") { if (url == "") {
url = getQuery() url = getQuery()
document.getElementById('url').value = url; document.getElementById('url').value = url;
} }
if (url[0] == '/') { if (url[0] == '/') {
url = window.location.protocol + '//' + window.location.host + url; url = window.location.protocol + '//' + window.location.host + url;
} }
if (url == "") { if (url == "") {
return; return;
} }
var request = new XMLHttpRequest(); var request = new XMLHttpRequest();
request.responseType = "blob"; request.responseType = "blob";
request.onreadystatechange = function () { request.onreadystatechange = function () {
if (request.readyState === XMLHttpRequest.DONE) { if (request.readyState === XMLHttpRequest.DONE) {
if (request.status === 200) { if (request.status === 200) {
console.log("request received"); console.log("request received");
data = request.response; data = request.response;
dataURL = URL.createObjectURL(data); dataURL = URL.createObjectURL(data);
var link = document.getElementById("link"); var link = document.getElementById("link");
link.href = dataURL; link.href = dataURL;
link.download = "media.ts"; link.download = "media.ts";
link.innerHTML = "Download"; link.innerHTML = "Download";
} else { } else {
console.log('There was a problem with the request. Status: ' + request.status); console.log('There was a problem with the request. Status: ' + request.status);
} }
} }
} }
request.open("GET", url, true); request.open("GET", url, true);
request.send(); request.send();
} }

12
cmd/audio-player/pcm-to-wav.js
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@ -24,24 +24,24 @@ LICENSE
// pcmToWav takes raw pcm data along with the sample rate, number of channels and bit-depth, // pcmToWav takes raw pcm data along with the sample rate, number of channels and bit-depth,
// and adds a WAV header to it so that it can be read and played by common players. // and adds a WAV header to it so that it can be read and played by common players.
// input and output data bytes are represented as arrays of 8 bit integers. // Input and output data bytes are represented as arrays of 8 bit integers.
// WAV spec.: http://soundfile.sapp.org/doc/WaveFormat/ // WAV spec.: http://soundfile.sapp.org/doc/WaveFormat/
function pcmToWav(data, rate, channels, bitdepth) { function pcmToWav(data, rate, channels, bitdepth) {
subChunk2ID = [100, 97, 116, 97]; // "data" subChunk2ID = [100, 97, 116, 97]; // "data".
subChunk2Size = int32ToBytes(data.length); subChunk2Size = int32ToBytes(data.length);
subChunk1ID = [102, 109, 116, 32]; // "fmt " subChunk1ID = [102, 109, 116, 32]; // "fmt ".
subChunk1Size = int32ToBytes(16); subChunk1Size = int32ToBytes(16);
audioFmt = int16ToBytes(1); // 1 = PCM audioFmt = int16ToBytes(1); // 1 = PCM.
numChannels = int16ToBytes(channels); numChannels = int16ToBytes(channels);
sampleRate = int32ToBytes(rate); sampleRate = int32ToBytes(rate);
byteRate = int32ToBytes(rate * channels * bitdepth / 8); byteRate = int32ToBytes(rate * channels * bitdepth / 8);
blockAlign = int16ToBytes(channels * bitdepth / 8); blockAlign = int16ToBytes(channels * bitdepth / 8);
bitsPerSample = int16ToBytes(bitdepth) bitsPerSample = int16ToBytes(bitdepth)
chunkID = [82, 73, 70, 70]; // "RIFF" chunkID = [82, 73, 70, 70]; // "RIFF".
chunkSize = int32ToBytes(36 + data.length); chunkSize = int32ToBytes(36 + data.length);
format = [87, 65, 86, 69]; // "WAVE" format = [87, 65, 86, 69]; // "WAVE".
result = chunkID; result = chunkID;
result.push(...chunkSize, ...format, ...subChunk1ID, ...subChunk1Size, ...audioFmt, ...numChannels, ...sampleRate, ...byteRate, ...blockAlign, ...bitsPerSample, ...subChunk2ID, ...subChunk2Size); result.push(...chunkSize, ...format, ...subChunk1ID, ...subChunk1Size, ...audioFmt, ...numChannels, ...sampleRate, ...byteRate, ...blockAlign, ...bitsPerSample, ...subChunk2ID, ...subChunk2Size);