wav - npm Package Compare versions

Comparing version 0.0.1 to 0.1.0

examples/wavinfo.js

 
 /**
- * Pipe a WAVE file to stdin, or specify the 
+ * Pipe a WAVE file to stdin, or specify the filename as the first argument,
+ * and information about the wave file will be printed out.
+ *
+ * Mimics the `wavinfo` program:
+ *   http://www.morphet.org.uk/comp/wavtools.html
  */
@@ -5,0 +9,0 @@

index.js

 
 /**
+ * References:
+ *  - http://www.sonicspot.com/guide/wavefiles.html
+ *  - https://ccrma.stanford.edu/courses/422/projects/WaveFormat/
+ *  - http://www-mmsp.ece.mcgill.ca/Documents/AudioFormats/WAVE/WAVE.html
+ *  - http://www.blitter.com/~russtopia/MIDI/~jglatt/tech/wave.htm
+ */
+
+/**
  * The `Reader` class accepts a WAVE audio file, emits a "format" event, and
@@ -4,0 +12,0 @@ * outputs the raw "data" from the WAVE file (usually raw PCM data, but if the

lib/file-writer.js

@@ -37,2 +37,4 @@
  * Emits a "done" event when everything is all good.
+ *
+ * @api private
  */
@@ -39,0 +41,0 @@

lib/reader.js

@@ -9,6 +9,10 @@
 var debug = require('debug')('wave:reader');
-var Parser = require('../parser');
+var Transform = require('stream').Transform;
+var Parser = require('stream-parser');
 var inherits = util.inherits;
 var f = util.format;
 
+// for node v0.8.x support, remove after v0.12.x
+if (!Transform) Transform = require('readable-stream/transform');
+
 /**
@@ -21,9 +25,10 @@ * Module exports.
 /**
- * The `Reader` class reads WAV audio files and output raw PCM audio data.
+ * The `Reader` class accepts a WAV audio file written to it and outputs the raw
+ * audio data with the WAV header stripped (most of the time, PCM audio data will
+ * be output, depending on the `audioFormat` property).
  *
- * References:
- *  - http://www.sonicspot.com/guide/wavefiles.html
- *  - https://ccrma.stanford.edu/courses/422/projects/WaveFormat/
- *  - http://www-mmsp.ece.mcgill.ca/Documents/AudioFormats/WAVE/WAVE.html
- *  - http://www.blitter.com/~russtopia/MIDI/~jglatt/tech/wave.htm
+ * A `"format"` event gets emitted after the WAV header has been parsed.
+ *
+ * @param {Object} opts optional options object
+ * @api public
  */
@@ -35,17 +40,28 @@
   }
-  Parser.call(this, opts);
-  this.endianness = 'LE';
-  this.buffer(4, this._onRiffID);
+  Transform.call(this, opts);
+
+  this._bytes(4, this._onRiffID);
 }
-inherits(Reader, Parser);
+inherits(Reader, Transform);
 
+/**
+ * Mixin `Parser`.
+ */
+
+Parser(Reader.prototype);
+
 // the beginning of the WAV file
 Reader.prototype._onRiffID = function (chunk) {
   debug('onRiffID:', chunk);
-  // TODO: support RIFX
-  this.riffId = chunk.toString('ascii');
-  if ('RIFF' === this.riffId) {
-    this.buffer(4, this._onChunkSize);
+  var id = this.riffId = chunk.toString('ascii');
+  if ('RIFF' === id) {
+    debug('detected little-endian WAVE file');
+    this.endianness = 'LE';
+    this._bytes(4, this._onChunkSize);
+  } else if ('RIFX' === id) {
+    debug('detected big-endian WAVE file');
+    this.endianness = 'BE';
+    this._bytes(4, this._onChunkSize);
   } else {
-    this.emit('error', new Error(f('bad "chunk id": expected "RIFF", got %j', this.riffId)));
+    this.emit('error', new Error(f('bad "chunk id": expected "RIFF" or "RIFX", got %j', id)));
   }
@@ -58,3 +74,3 @@ };
   this.chunkSize = chunk['readUInt32' + this.endianness](0);
-  this.buffer(4, this._onFormat);
+  this._bytes(4, this._onFormat);
 };
@@ -67,3 +83,3 @@
   if ('WAVE' === this.waveId) {
-    this.buffer(4, this._onSubchunk1ID);
+    this._bytes(4, this._onSubchunk1ID);
   } else {
@@ -80,3 +96,3 @@ this.emit('error', new Error(f('bad "format": expected "WAVE", got %j', this.waveId)));
   if ('fmt ' === subchunk1ID) {
-    this.buffer(4, this._onSubchunk1Size);
+    this._bytes(4, this._onSubchunk1Size);
   } else {
@@ -91,3 +107,3 @@ this.emit('error', new Error(f('bad "fmt id": expected "fmt ", got %j', subchunk1ID)));
   // TODO: assert should be 16 for PCM
-  this.buffer(this.subchunk1Size, this._onSubchunk1);
+  this._bytes(this.subchunk1Size, this._onSubchunk1);
 };
@@ -108,2 +124,3 @@
     audioFormat: this.audioFormat,
+    endianness: this.endianness,
     channels: this.channels,
@@ -117,3 +134,3 @@ sampleRate: this.sampleRate,
 
-  this.buffer(4, this._onSubchunk2ID);
+  this._bytes(4, this._onSubchunk2ID);
 };
@@ -125,3 +142,3 @@
   if ('data' === subchunk2ID) {
-    this.buffer(4, this._onSubchunk2Size);
+    this._bytes(4, this._onSubchunk2Size);
   } else {
@@ -136,8 +153,10 @@ this.emit('error', new Error(f('bad "data" chunk: expected "data", got %j', subchunk2ID)));
   this.subchunk2Size = chunk['readUInt32' + this.endianness](0);
-  this.passthrough(this.subchunk2Size, this._onEnd);
-};
 
-Reader.prototype._onEnd = function () {
-  debug('onEnd');
-  this.done = true;
+  // even though the WAV file reports a remaining byte length, in practice it
+  // can't really be trusted since in streaming situations where the WAV file is
+  // being generated on-the-fly, the number of remaining bytes would be impossible
+  // to know beforehand. For this reason, some encoders write `0` for the byte
+  // length here... In any case, we are just gonna pass through the rest of the
+  // stream until EOF.
+  this._passthrough(Infinity, this._onEnd);
 };

lib/writer.js

@@ -9,4 +9,8 @@
 var debug = require('debug')('wave:writer');
-var Parser = require('../parser');
+var Transform = require('stream').Transform;
+var Parser = require('stream-parser');
 
+// for node v0.8.x support, remove after v0.12.x
+if (!Transform) Transform = require('readable-stream/transform');
+
 /**
@@ -20,2 +24,4 @@ * Module exports.
  * RIFF Chunk IDs in Buffers.
+ *
+ * @api private
  */
@@ -31,2 +37,4 @@
  * 32-bit int value, minus 100 bytes (overkill, 44 would be safe) for the header.
+ *
+ * @api private
  */
@@ -37,3 +45,22 @@
 /**
- * The `Writer` class.
+ * The `Writer` class accepts raw audio data written to it (only PCM audio data is
+ * currently supported), and outputs a WAV file with a valid WAVE header at the
+ * beginning specifying the formatting information of the audio stream.
+ *
+ * Note that there's an interesting problem, because the WAVE header also
+ * specifies the total byte length of the audio data in the file, and there's no
+ * way that we can know this ahead of time. Therefore the WAVE header will contain
+ * a byte-length if `0` initially, which most WAVE decoders will know means to
+ * just read until `EOF`.
+ *
+ * Optionally, if you are in a situation where you can seek back to the beginning
+ * of the destination of the WAVE file (like writing to a regular file, for
+ * example), then you may listen for the `"header"` event which will be emitted
+ * _after_ all the data has been written, and you can go back and rewrite the new
+ * header with proper audio byte length into the beginning of the destination
+ * (though if your destination _is_ a regular file, you should use the the
+ * `FileWriter` class instead).
+ *
+ * @param {Object} opts optional options object
+ * @api public
  */
@@ -45,6 +72,6 @@
   }
-  Parser.call(this, opts);
+  Transform.call(this, opts);
 
+  // TODO: allow/properly handle other WAVE audio formats
   this.endianness = 'LE';
-
   this.format = 1; // raw PCM
@@ -64,8 +91,16 @@ this.channels = 2;
   //this.immediate(this._writeHeader);
-  this.buffer(0, this._writeHeader);
+  this._bytes(0, this._writeHeader);
 }
-inherits(Writer, Parser);
+inherits(Writer, Transform);
 
 /**
+ * Mixin `Parser`.
+ */
+
+Parser(Writer.prototype);
+
+/**
  * Writes the WAVE header.
+ *
+ * @api private
  */
@@ -78,3 +113,6 @@
   var dataLength = this.dataLength;
-  if (null == dataLength) dataLength = MAX_WAV;
+  if (null == dataLength) {
+    debug('using default "dataLength" of %d', MAX_WAV);
+    dataLength = MAX_WAV;
+  }
   var fileSize = dataLength + headerLength;
@@ -155,5 +193,11 @@ var header = new Buffer(headerLength);
   write(header);
-  this.passthrough(dataLength, this._onEnd);
+  this._passthrough(dataLength, this._onEnd);
 };
 
+/**
+ * Called for the "end" event of this Writer instance.
+ *
+ * @api private
+ */
+
 Writer.prototype._onEnd = function (write) {
@@ -165,2 +209,4 @@ debug('_onEnd()');
  * Emits a "header" event after the readable side of the stream has finished.
+ *
+ * @api private
  */
@@ -182,2 +228,4 @@
  * it's good to when when possible.
+ *
+ * @api private
  */
@@ -184,0 +232,0 @@

package.json

 {
   "name": "wav",
   "description": "`Reader` and `Writer` streams for Microsoft WAVE audio files",
-  "version": "0.0.1",
+  "version": "0.1.0",
   "author": "Nathan Rajlich <[e-mail]>",
@@ -13,2 +13,3 @@ "repository": {
     "debug": "*",
+    "stream-parser": "*",
     "readable-stream": "~0.0.3"
@@ -21,7 +22,7 @@ },
   "scripts": {
-    "test": "mocha"
+    "test": "mocha --reporter spec"
   },
   "engines": {
-    "node": "*"
+    "node": ">= v0.8.x"
   }
 }

README.md

 node-wav
 ========
 ### `Reader` and `Writer` streams for Microsoft WAVE audio files
+[![Build Status](https://secure.travis-ci.org/TooTallNate/node-wav.png)](http://travis-ci.org/TooTallNate/node-wav)
 
@@ -47,9 +48,36 @@ This module offers streams to help work with Microsoft WAVE files.
 
-### Reader class
+  - [Reader()](#reader)
+  - [Writer()](#writer)
+  - [FileWriter()](#filewriter)
 
+## Reader()
 
-### Writer class
+The `Reader` class accepts a WAV audio file written to it and outputs the raw
+audio data with the WAV header stripped (most of the time, PCM audio data will
+be output, depending on the `audioFormat` property).
 
+A `"format"` event gets emitted after the WAV header has been parsed.
 
-### FileWriter class
+## Writer()
 
+The `Writer` class accepts raw audio data written to it (only PCM audio data is
+currently supported), and outputs a WAV file with a valid WAVE header at the
+beginning specifying the formatting information of the audio stream.
+
+Note that there's an interesting problem, because the WAVE header also
+specifies the total byte length of the audio data in the file, and there's no
+way that we can know this ahead of time. Therefore the WAVE header will contain
+a byte-length if `0` initially, which most WAVE decoders will know means to
+just read until `EOF`.
+
+Optionally, if you are in a situation where you can seek back to the beginning
+of the destination of the WAVE file (like writing to a regular file, for
+example), then you may listen for the `"header"` event which will be emitted
+_after_ all the data has been written, and you can go back and rewrite the new
+header with proper audio byte length into the beginning of the destination
+(though if your destination _is_ a regular file, you should use the the
+`FileWriter` class instead).
+
+## FileWriter()
+
+The `FileWriter` class.

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Improved metrics

Total package byte prevSize

1056175

increased by34.28%

Number of package files

47

increased by2.17%

Lines of code

545

increased by12.14%

Number of lines in readme file

83

increased by50.91%

Number of medium supply chain risk alerts

35

decreased by-2.78%

Worsened metrics

Dependency count

3

increased by50%

Number of medium quality alerts

2

increased by100%

Number of low supply chain risk alerts

3

increased by50%

Dependency changes

• + Addedstream-parser@*

• + Addeddebug@2.6.9(transitive)

• + Addedms@2.0.0(transitive)

• + Addedstream-parser@0.3.1(transitive)