87 lines
2.6 KiB
JavaScript
87 lines
2.6 KiB
JavaScript
var util = require("util");
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var MetaDataBlock = require("./MetaDataBlock");
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var MetaDataBlockStreamInfo = module.exports = function(isLast) {
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MetaDataBlock.call(this, isLast, 0);
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this.minBlockSize = 0;
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this.maxBlockSize = 0;
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this.minFrameSize = 0;
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this.maxFrameSize = 0;
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this.sampleRate = 0;
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this.channels = 0;
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this.bitsPerSample = 0;
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this.samples = 0;
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this.checksum = null;
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this.duration = 0;
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this.durationStr = "0:00.000";
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}
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util.inherits(MetaDataBlockStreamInfo, MetaDataBlock);
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MetaDataBlockStreamInfo.prototype.remove = function() {
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console.error("WARNING: Can't remove StreamInfo block!");
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}
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MetaDataBlockStreamInfo.prototype.parse = function(buffer) {
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try {
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var pos = 0;
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this.minBlockSize = buffer.readUInt16BE(pos);
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this.maxBlockSize = buffer.readUInt16BE(pos + 2);
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this.minFrameSize = (buffer.readUInt8(pos + 4) << 16) | buffer.readUInt16BE(pos + 5);
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this.maxFrameSize = (buffer.readUInt8(pos + 7) << 16) | buffer.readUInt16BE(pos + 8);
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var tmp = buffer.readUInt32BE(pos + 10);
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this.sampleRate = tmp >>> 12;
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this.channels = (tmp >>> 9) & 0x07;
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this.bitsPerSample = (tmp >>> 4) & 0x1f;
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this.samples = +((tmp & 0x0f) << 4) + buffer.readUInt32BE(pos + 14);
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this.checksum = new Buffer(16);
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buffer.copy(this.checksum, 0, 18, 34);
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this.duration = this.samples / this.sampleRate;
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var minutes = "" + Math.floor(this.duration / 60);
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var seconds = pad(Math.floor(this.duration % 60), 2);
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var milliseconds = pad(Math.round(((this.duration % 60) - Math.floor(this.duration % 60)) * 1000), 3);
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this.durationStr = minutes + ":" + seconds + "." + milliseconds;
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this.hasData = true;
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}
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catch (e) {
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this.error = e;
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this.hasData = false;
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}
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}
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MetaDataBlockStreamInfo.prototype.toString = function() {
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var str = "[MetaDataBlockStreamInfo]";
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str += " type: " + this.type;
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str += ", isLast: " + this.isLast;
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if (this.error) {
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str += "\n ERROR: " + this.error;
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}
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if (this.hasData) {
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str += "\n minBlockSize: " + this.minBlockSize;
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str += "\n maxBlockSize: " + this.maxBlockSize;
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str += "\n minFrameSize: " + this.minFrameSize;
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str += "\n maxFrameSize: " + this.maxFrameSize;
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str += "\n samples: " + this.samples;
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str += "\n sampleRate: " + this.sampleRate;
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str += "\n channels: " + (this.channels + 1);
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str += "\n bitsPerSample: " + (this.bitsPerSample + 1);
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str += "\n duration: " + this.durationStr;
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str += "\n checksum: " + (this.checksum ? this.checksum.toString("hex") : "<null>");
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}
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return str;
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}
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function pad(n, width) {
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n = "" + n;
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return (n.length >= width) ? n : new Array(width - n.length + 1).join("0") + n;
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}
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