WaveFileCreator.bitDepthFromFmt_ - Code Metrics - Inspection of "Add the WaveFileMetaEditor class" - rochars/wavefile - Measure and Improve Code Quality continuously with Scrutinizer

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Push — master ( 6ca9b2...ebd43e )

by Rafael S.

created 2019-08-13 15:05 UTC

WaveFileCreator.bitDepthFromFmt_ A

↳ Parent: WaveFileCreator

Complexity

Conditions

Size

Total Lines	11
Code Lines	9

Duplication

Lines	0
Ratio	0 %

Importance

Changes

Metric	Value
eloc	9
dl	0
loc	11
rs	9.95
c	0
b	0
f	0
cc	4

/*
 * Copyright (c) 2017-2019 Rafael da Silva Rocha.
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 */

/**
 * @fileoverview The WaveFileCreator class.
 * @see https://github.com/rochars/wavefile
 */

/** @module wavefile */

import WaveFileParser from './wavefile-parser';
import interleave from './interleave';
import dwChannelMask from './dw-channel-mask';
import validateNumChannels from './validate-num-channels'; 
import validateSampleRate from './validate-sample-rate';
import {packArrayTo, packTo, unpack} from 'byte-data';

/**
 * A class to read, write and create wav files.
 * @extends WaveFileParser
 */
export default class WaveFileCreator extends WaveFileParser {

  constructor() {
    super();
    /**
     * The bit depth code according to the samples.
     * @type {string}
     */
    this.bitDepth = '0';
    /**
     * @type {!Object}
     * @protected
     */
    this.dataType = {};
    /**
     * Audio formats.
     * Formats not listed here should be set to 65534,
     * the code for WAVE_FORMAT_EXTENSIBLE
     * @enum {number}
     * @protected
     */
    this.WAV_AUDIO_FORMATS = {
      '4': 17,
      '8': 1,
      '8a': 6,
      '8m': 7,
      '16': 1,
      '24': 1,
      '32': 1,
      '32f': 3,
      '64': 3
    };
  }

  /**
   * Set up the WaveFileCreator object based on the arguments passed.
   * @param {number} numChannels The number of channels
   *    (Integer numbers: 1 for mono, 2 stereo and so on).
   * @param {number} sampleRate The sample rate.
   *    Integer numbers like 8000, 44100, 48000, 96000, 192000.
   * @param {string} bitDepthCode The audio bit depth code.
   *    One of '4', '8', '8a', '8m', '16', '24', '32', '32f', '64'
   *    or any value between '8' and '32' (like '12').
   * @param {!Array<number>|!Array<!Array<number>>|!TypedArray} samples
   *    The samples. Must be in the correct range according to the bit depth.
   * @param {?Object} options Optional. Used to force the container
   *    as RIFX with {'container': 'RIFX'}
   * @throws {Error} If any argument does not meet the criteria.
   */
  fromScratch(numChannels, sampleRate, bitDepthCode, samples, options={}) {
    if (!options.container) {
      options.container = 'RIFF';
    }
    this.container = options.container;
    this.bitDepth = bitDepthCode;
    samples = interleave(samples);
    this.updateDataType_();
    /** @type {number} */
    let numBytes = this.dataType.bits / 8;
    this.data.samples = new Uint8Array(samples.length * numBytes);
    packArrayTo(samples, this.dataType, this.data.samples);
    this.clearHeader();
    this.makeWavHeader_(
      bitDepthCode, numChannels, sampleRate,
      numBytes, this.data.samples.length, options);
    this.data.chunkId = 'data';
    this.data.chunkSize = this.data.samples.length;
    this.validateWavHeader_();
  }

  /**
   * Set up the WaveFileParser object from a byte buffer.
   * @param {!Uint8Array} wavBuffer The buffer.
   * @param {boolean=} samples True if the samples should be loaded.
   * @throws {Error} If container is not RIFF, RIFX or RF64.
   * @throws {Error} If format is not WAVE.
   * @throws {Error} If no 'fmt ' chunk is found.
   * @throws {Error} If no 'data' chunk is found.
   */
  fromBuffer(wavBuffer, samples=true) {
    super.fromBuffer(wavBuffer, samples);
    this.bitDepthFromFmt_();
    this.updateDataType_();
  }

  /**
   * Return a byte buffer representig the WaveFileParser object as a .wav file.
   * The return value of this method can be written straight to disk.
   * @return {!Uint8Array} A wav file.
   * @throws {Error} If bit depth is invalid.
   * @throws {Error} If the number of channels is invalid.
   * @throws {Error} If the sample rate is invalid.
   */
  toBuffer() {
    this.validateWavHeader_();
    return super.toBuffer();
  }

    /**
   * Return the sample at a given index.
   * @param {number} index The sample index.
   * @return {number} The sample.
   * @throws {Error} If the sample index is off range.
   */
  getSample(index) {
    index = index * (this.dataType.bits / 8);
    if (index + this.dataType.bits / 8 > this.data.samples.length) {
      throw new Error('Range error');
    }
    return unpack(
      this.data.samples.slice(index, index + this.dataType.bits / 8),
      this.dataType);
  }

  /**
   * Set the sample at a given index.
   * @param {number} index The sample index.
   * @param {number} sample The sample.
   * @throws {Error} If the sample index is off range.
   */
  setSample(index, sample) {
    index = index * (this.dataType.bits / 8);
    if (index + this.dataType.bits / 8 > this.data.samples.length) {
      throw new Error('Range error');
    }
    packTo(sample, this.dataType, this.data.samples, index);
  }

  /**
   * Define the header of a wav file.
   * @param {string} bitDepthCode The audio bit depth
   * @param {number} numChannels The number of channels
   * @param {number} sampleRate The sample rate.
   * @param {number} numBytes The number of bytes each sample use.
   * @param {number} samplesLength The length of the samples in bytes.
   * @param {!Object} options The extra options, like container defintion.
   * @private
   */
  makeWavHeader_(
    bitDepthCode, numChannels, sampleRate, numBytes, samplesLength, options) {
    if (bitDepthCode == '4') {
      this.createADPCMHeader_(
        bitDepthCode, numChannels, sampleRate, numBytes, samplesLength, options);

    } else if (bitDepthCode == '8a' || bitDepthCode == '8m') {
      this.createALawMulawHeader_(
        bitDepthCode, numChannels, sampleRate, numBytes, samplesLength, options);

    } else if(Object.keys(this.WAV_AUDIO_FORMATS).indexOf(bitDepthCode) == -1 ||
        numChannels > 2) {
      this.createExtensibleHeader_(
        bitDepthCode, numChannels, sampleRate, numBytes, samplesLength, options);

    } else {
      this.createPCMHeader_(
        bitDepthCode, numChannels, sampleRate, numBytes, samplesLength, options);      
    }
  }

  /**
   * Create the header of a linear PCM wave file.
   * @param {string} bitDepthCode The audio bit depth
   * @param {number} numChannels The number of channels
   * @param {number} sampleRate The sample rate.
   * @param {number} numBytes The number of bytes each sample use.
   * @param {number} samplesLength The length of the samples in bytes.
   * @param {!Object} options The extra options, like container defintion.
   * @private
   */
  createPCMHeader_(
    bitDepthCode, numChannels, sampleRate, numBytes, samplesLength, options) {
    this.container = options.container;
    this.chunkSize = 36 + samplesLength;
    this.format = 'WAVE';
    this.bitDepth = bitDepthCode;
    this.fmt = {
      chunkId: 'fmt ',
      chunkSize: 16,
      audioFormat: this.WAV_AUDIO_FORMATS[bitDepthCode] || 65534,
      numChannels: numChannels,
      sampleRate: sampleRate,
      byteRate: (numChannels * numBytes) * sampleRate,
      blockAlign: numChannels * numBytes,
      bitsPerSample: parseInt(bitDepthCode, 10),
      cbSize: 0,
      validBitsPerSample: 0,
      dwChannelMask: 0,
      subformat: []
    };
  }

  /**
   * Create the header of a ADPCM wave file.
   * @param {string} bitDepthCode The audio bit depth
   * @param {number} numChannels The number of channels
   * @param {number} sampleRate The sample rate.
   * @param {number} numBytes The number of bytes each sample use.
   * @param {number} samplesLength The length of the samples in bytes.
   * @param {!Object} options The extra options, like container defintion.
   * @private
   */
  createADPCMHeader_(
    bitDepthCode, numChannels, sampleRate, numBytes, samplesLength, options) {
    this.createPCMHeader_(
      bitDepthCode, numChannels, sampleRate, numBytes, samplesLength, options);
    this.chunkSize = 40 + samplesLength;
    this.fmt.chunkSize = 20;
    this.fmt.byteRate = 4055;
    this.fmt.blockAlign = 256;
    this.fmt.bitsPerSample = 4;
    this.fmt.cbSize = 2;
    this.fmt.validBitsPerSample = 505;
    this.fact = {
      chunkId: 'fact',
      chunkSize: 4,
      dwSampleLength: samplesLength * 2
    };
  }

  /**
   * Create the header of WAVE_FORMAT_EXTENSIBLE file.
   * @param {string} bitDepthCode The audio bit depth
   * @param {number} numChannels The number of channels
   * @param {number} sampleRate The sample rate.
   * @param {number} numBytes The number of bytes each sample use.
   * @param {number} samplesLength The length of the samples in bytes.
   * @param {!Object} options The extra options, like container defintion.
   * @private
   */
  createExtensibleHeader_(
      bitDepthCode, numChannels, sampleRate, numBytes, samplesLength, options) {
    this.createPCMHeader_(
      bitDepthCode, numChannels, sampleRate, numBytes, samplesLength, options);
    this.chunkSize = 36 + 24 + samplesLength;
    this.fmt.chunkSize = 40;
    this.fmt.bitsPerSample = ((parseInt(bitDepthCode, 10) - 1) | 7) + 1;
    this.fmt.cbSize = 22;
    this.fmt.validBitsPerSample = parseInt(bitDepthCode, 10);
    this.fmt.dwChannelMask = dwChannelMask(numChannels);
    // subformat 128-bit GUID as 4 32-bit values
    // only supports uncompressed integer PCM samples
    this.fmt.subformat = [1, 1048576, 2852126848, 1905997824];
  }

  /**
   * Create the header of mu-Law and A-Law wave files.
   * @param {string} bitDepthCode The audio bit depth
   * @param {number} numChannels The number of channels
   * @param {number} sampleRate The sample rate.
   * @param {number} numBytes The number of bytes each sample use.
   * @param {number} samplesLength The length of the samples in bytes.
   * @param {!Object} options The extra options, like container defintion.
   * @private
   */
  createALawMulawHeader_(
      bitDepthCode, numChannels, sampleRate, numBytes, samplesLength, options) {
    this.createPCMHeader_(
      bitDepthCode, numChannels, sampleRate, numBytes, samplesLength, options);
    this.chunkSize = 40 + samplesLength;
    this.fmt.chunkSize = 20;
    this.fmt.cbSize = 2;
    this.fmt.validBitsPerSample = 8;
    this.fact = {
      chunkId: 'fact',
      chunkSize: 4,
      dwSampleLength: samplesLength
    };
  }

  /**
   * Set the string code of the bit depth based on the 'fmt ' chunk.
   * @private
   */
  bitDepthFromFmt_() {
    if (this.fmt.audioFormat === 3 && this.fmt.bitsPerSample === 32) {
      this.bitDepth = '32f';
    } else if (this.fmt.audioFormat === 6) {
      this.bitDepth = '8a';
    } else if (this.fmt.audioFormat === 7) {
      this.bitDepth = '8m';
    } else {
      this.bitDepth = this.fmt.bitsPerSample.toString();
    }
  }

  /**
   * Validate the bit depth.
   * @return {boolean} True is the bit depth is valid.
   * @throws {Error} If bit depth is invalid.
   * @private
   */
  validateBitDepth_() {
    if (!this.WAV_AUDIO_FORMATS[this.bitDepth]) {
      if (parseInt(this.bitDepth, 10) > 8 &&
          parseInt(this.bitDepth, 10) < 54) {
        return true;
      }
      throw new Error('Invalid bit depth.');
    }
    return true;
  }

  /**
   * Update the type definition used to read and write the samples.
   * @private
   */
  updateDataType_() {
    this.dataType = {
      bits: ((parseInt(this.bitDepth, 10) - 1) | 7) + 1,
      fp: this.bitDepth == '32f' || this.bitDepth == '64',
      signed: this.bitDepth != '8',
      be: this.container == 'RIFX'
    };
    if (['4', '8a', '8m'].indexOf(this.bitDepth) > -1 ) {
      this.dataType.bits = 8;
      this.dataType.signed = false;
    }
  }

  /**
   * Validate the header of the file.
   * @throws {Error} If bit depth is invalid.
   * @throws {Error} If the number of channels is invalid.
   * @throws {Error} If the sample rate is invalid.
   * @ignore
   * @private
   */
  validateWavHeader_() {
    this.validateBitDepth_();
    if (!validateNumChannels(this.fmt.numChannels, this.fmt.bitsPerSample)) {
      throw new Error('Invalid number of channels.');
    }
    if (!validateSampleRate(
        this.fmt.numChannels, this.fmt.bitsPerSample, this.fmt.sampleRate)) {
      throw new Error('Invalid sample rate.');
    }
  }
}


1			/*
2			* Copyright (c) 2017-2019 Rafael da Silva Rocha.
3			*
4			* Permission is hereby granted, free of charge, to any person obtaining
5			* a copy of this software and associated documentation files (the
6			* "Software"), to deal in the Software without restriction, including
7			* without limitation the rights to use, copy, modify, merge, publish,
8			* distribute, sublicense, and/or sell copies of the Software, and to
9			* permit persons to whom the Software is furnished to do so, subject to
10			* the following conditions:
11			*
12			* The above copyright notice and this permission notice shall be
13			* included in all copies or substantial portions of the Software.
14			*
15			* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
16			* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
17			* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
18			* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
19			* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
20			* OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
21			* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
22			*
23			*/
24
25			/**
26			* @fileoverview The WaveFileCreator class.
27			* @see https://github.com/rochars/wavefile
28			*/
29
30			/** @module wavefile */
31
32			import WaveFileParser from './wavefile-parser';
33			import interleave from './interleave';
34			import dwChannelMask from './dw-channel-mask';
35			import validateNumChannels from './validate-num-channels';
36			import validateSampleRate from './validate-sample-rate';
37			import {packArrayTo, packTo, unpack} from 'byte-data';
38
39			/**
40			* A class to read, write and create wav files.
41			* @extends WaveFileParser
42			*/
43			export default class WaveFileCreator extends WaveFileParser {
44
45			constructor() {
46			super();
47			/**
48			* The bit depth code according to the samples.
49			* @type {string}
50			*/
51			this.bitDepth = '0';
52			/**
53			* @type {!Object}
54			* @protected
55			*/
56			this.dataType = {};
57			/**
58			* Audio formats.
59			* Formats not listed here should be set to 65534,
60			* the code for WAVE_FORMAT_EXTENSIBLE
61			* @enum {number}
62			* @protected
63			*/
64			this.WAV_AUDIO_FORMATS = {
65			'4': 17,
66			'8': 1,
67			'8a': 6,
68			'8m': 7,
69			'16': 1,
70			'24': 1,
71			'32': 1,
72			'32f': 3,
73			'64': 3
74			};
75			}
76
77			/**
78			* Set up the WaveFileCreator object based on the arguments passed.
79			* @param {number} numChannels The number of channels
80			* (Integer numbers: 1 for mono, 2 stereo and so on).
81			* @param {number} sampleRate The sample rate.
82			* Integer numbers like 8000, 44100, 48000, 96000, 192000.
83			* @param {string} bitDepthCode The audio bit depth code.
84			* One of '4', '8', '8a', '8m', '16', '24', '32', '32f', '64'
85			* or any value between '8' and '32' (like '12').
86			* @param {!Array<number>\|!Array<!Array<number>>\|!TypedArray} samples
87			* The samples. Must be in the correct range according to the bit depth.
88			* @param {?Object} options Optional. Used to force the container
89			* as RIFX with {'container': 'RIFX'}
90			* @throws {Error} If any argument does not meet the criteria.
91			*/
92			fromScratch(numChannels, sampleRate, bitDepthCode, samples, options={}) {
93			if (!options.container) {
94			options.container = 'RIFF';
95			}
96			this.container = options.container;
97			this.bitDepth = bitDepthCode;
98			samples = interleave(samples);
99			this.updateDataType_();
100			/** @type {number} */
101			let numBytes = this.dataType.bits / 8;
102			this.data.samples = new Uint8Array(samples.length * numBytes);
103			packArrayTo(samples, this.dataType, this.data.samples);
104			this.clearHeader();
105			this.makeWavHeader_(
106			bitDepthCode, numChannels, sampleRate,
107			numBytes, this.data.samples.length, options);
108			this.data.chunkId = 'data';
109			this.data.chunkSize = this.data.samples.length;
110			this.validateWavHeader_();
111			}
112
113			/**
114			* Set up the WaveFileParser object from a byte buffer.
115			* @param {!Uint8Array} wavBuffer The buffer.
116			* @param {boolean=} samples True if the samples should be loaded.
117			* @throws {Error} If container is not RIFF, RIFX or RF64.
118			* @throws {Error} If format is not WAVE.
119			* @throws {Error} If no 'fmt ' chunk is found.
120			* @throws {Error} If no 'data' chunk is found.
121			*/
122			fromBuffer(wavBuffer, samples=true) {
123			super.fromBuffer(wavBuffer, samples);
124			this.bitDepthFromFmt_();
125			this.updateDataType_();
126			}
127
128			/**
129			* Return a byte buffer representig the WaveFileParser object as a .wav file.
130			* The return value of this method can be written straight to disk.
131			* @return {!Uint8Array} A wav file.
132			* @throws {Error} If bit depth is invalid.
133			* @throws {Error} If the number of channels is invalid.
134			* @throws {Error} If the sample rate is invalid.
135			*/
136			toBuffer() {
137			this.validateWavHeader_();
138			return super.toBuffer();
139			}
140
141			/**
142			* Return the sample at a given index.
143			* @param {number} index The sample index.
144			* @return {number} The sample.
145			* @throws {Error} If the sample index is off range.
146			*/
147			getSample(index) {
148			index = index * (this.dataType.bits / 8);
149			if (index + this.dataType.bits / 8 > this.data.samples.length) {
150			throw new Error('Range error');
151			}
152			return unpack(
153			this.data.samples.slice(index, index + this.dataType.bits / 8),
154			this.dataType);
155			}
156
157			/**
158			* Set the sample at a given index.
159			* @param {number} index The sample index.
160			* @param {number} sample The sample.
161			* @throws {Error} If the sample index is off range.
162			*/
163			setSample(index, sample) {
164			index = index * (this.dataType.bits / 8);
165			if (index + this.dataType.bits / 8 > this.data.samples.length) {
166			throw new Error('Range error');
167			}
168			packTo(sample, this.dataType, this.data.samples, index);
169			}
170
171			/**
172			* Define the header of a wav file.
173			* @param {string} bitDepthCode The audio bit depth
174			* @param {number} numChannels The number of channels
175			* @param {number} sampleRate The sample rate.
176			* @param {number} numBytes The number of bytes each sample use.
177			* @param {number} samplesLength The length of the samples in bytes.
178			* @param {!Object} options The extra options, like container defintion.
179			* @private
180			*/
181			makeWavHeader_(
182			bitDepthCode, numChannels, sampleRate, numBytes, samplesLength, options) {
183			if (bitDepthCode == '4') {
184			this.createADPCMHeader_(
185			bitDepthCode, numChannels, sampleRate, numBytes, samplesLength, options);
186
187			} else if (bitDepthCode == '8a' \|\| bitDepthCode == '8m') {
188			this.createALawMulawHeader_(
189			bitDepthCode, numChannels, sampleRate, numBytes, samplesLength, options);
190
191			} else if(Object.keys(this.WAV_AUDIO_FORMATS).indexOf(bitDepthCode) == -1 \|\|
192			numChannels > 2) {
193			this.createExtensibleHeader_(
194			bitDepthCode, numChannels, sampleRate, numBytes, samplesLength, options);
195
196			} else {
197			this.createPCMHeader_(
198			bitDepthCode, numChannels, sampleRate, numBytes, samplesLength, options);
199			}
200			}
201
202			/**
203			* Create the header of a linear PCM wave file.
204			* @param {string} bitDepthCode The audio bit depth
205			* @param {number} numChannels The number of channels
206			* @param {number} sampleRate The sample rate.
207			* @param {number} numBytes The number of bytes each sample use.
208			* @param {number} samplesLength The length of the samples in bytes.
209			* @param {!Object} options The extra options, like container defintion.
210			* @private
211			*/
212			createPCMHeader_(
213			bitDepthCode, numChannels, sampleRate, numBytes, samplesLength, options) {
214			this.container = options.container;
215			this.chunkSize = 36 + samplesLength;
216			this.format = 'WAVE';
217			this.bitDepth = bitDepthCode;
218			this.fmt = {
219			chunkId: 'fmt ',
220			chunkSize: 16,
221			audioFormat: this.WAV_AUDIO_FORMATS[bitDepthCode] \|\| 65534,
222			numChannels: numChannels,
223			sampleRate: sampleRate,
224			byteRate: (numChannels * numBytes) * sampleRate,
225			blockAlign: numChannels * numBytes,
226			bitsPerSample: parseInt(bitDepthCode, 10),
227			cbSize: 0,
228			validBitsPerSample: 0,
229			dwChannelMask: 0,
230			subformat: []
231			};
232			}
233
234			/**
235			* Create the header of a ADPCM wave file.
236			* @param {string} bitDepthCode The audio bit depth
237			* @param {number} numChannels The number of channels
238			* @param {number} sampleRate The sample rate.
239			* @param {number} numBytes The number of bytes each sample use.
240			* @param {number} samplesLength The length of the samples in bytes.
241			* @param {!Object} options The extra options, like container defintion.
242			* @private
243			*/
244			createADPCMHeader_(
245			bitDepthCode, numChannels, sampleRate, numBytes, samplesLength, options) {
246			this.createPCMHeader_(
247			bitDepthCode, numChannels, sampleRate, numBytes, samplesLength, options);
248			this.chunkSize = 40 + samplesLength;
249			this.fmt.chunkSize = 20;
250			this.fmt.byteRate = 4055;
251			this.fmt.blockAlign = 256;
252			this.fmt.bitsPerSample = 4;
253			this.fmt.cbSize = 2;
254			this.fmt.validBitsPerSample = 505;
255			this.fact = {
256			chunkId: 'fact',
257			chunkSize: 4,
258			dwSampleLength: samplesLength * 2
259			};
260			}
261
262			/**
263			* Create the header of WAVE_FORMAT_EXTENSIBLE file.
264			* @param {string} bitDepthCode The audio bit depth
265			* @param {number} numChannels The number of channels
266			* @param {number} sampleRate The sample rate.
267			* @param {number} numBytes The number of bytes each sample use.
268			* @param {number} samplesLength The length of the samples in bytes.
269			* @param {!Object} options The extra options, like container defintion.
270			* @private
271			*/
272			createExtensibleHeader_(
273			bitDepthCode, numChannels, sampleRate, numBytes, samplesLength, options) {
274			this.createPCMHeader_(
275			bitDepthCode, numChannels, sampleRate, numBytes, samplesLength, options);
276			this.chunkSize = 36 + 24 + samplesLength;
277			this.fmt.chunkSize = 40;
278			this.fmt.bitsPerSample = ((parseInt(bitDepthCode, 10) - 1) \| 7) + 1;
279			this.fmt.cbSize = 22;
280			this.fmt.validBitsPerSample = parseInt(bitDepthCode, 10);
281			this.fmt.dwChannelMask = dwChannelMask(numChannels);
282			// subformat 128-bit GUID as 4 32-bit values
283			// only supports uncompressed integer PCM samples
284			this.fmt.subformat = [1, 1048576, 2852126848, 1905997824];
285			}
286
287			/**
288			* Create the header of mu-Law and A-Law wave files.
289			* @param {string} bitDepthCode The audio bit depth
290			* @param {number} numChannels The number of channels
291			* @param {number} sampleRate The sample rate.
292			* @param {number} numBytes The number of bytes each sample use.
293			* @param {number} samplesLength The length of the samples in bytes.
294			* @param {!Object} options The extra options, like container defintion.
295			* @private
296			*/
297			createALawMulawHeader_(
298			bitDepthCode, numChannels, sampleRate, numBytes, samplesLength, options) {
299			this.createPCMHeader_(
300			bitDepthCode, numChannels, sampleRate, numBytes, samplesLength, options);
301			this.chunkSize = 40 + samplesLength;
302			this.fmt.chunkSize = 20;
303			this.fmt.cbSize = 2;
304			this.fmt.validBitsPerSample = 8;
305			this.fact = {
306			chunkId: 'fact',
307			chunkSize: 4,
308			dwSampleLength: samplesLength
309			};
310			}
311
312			/**
313			* Set the string code of the bit depth based on the 'fmt ' chunk.
314			* @private
315			*/
316			bitDepthFromFmt_() {
317			if (this.fmt.audioFormat === 3 && this.fmt.bitsPerSample === 32) {
318			this.bitDepth = '32f';
319			} else if (this.fmt.audioFormat === 6) {
320			this.bitDepth = '8a';
321			} else if (this.fmt.audioFormat === 7) {
322			this.bitDepth = '8m';
323			} else {
324			this.bitDepth = this.fmt.bitsPerSample.toString();
325			}
326			}
327
328			/**
329			* Validate the bit depth.
330			* @return {boolean} True is the bit depth is valid.
331			* @throws {Error} If bit depth is invalid.
332			* @private
333			*/
334			validateBitDepth_() {
335			if (!this.WAV_AUDIO_FORMATS[this.bitDepth]) {
336			if (parseInt(this.bitDepth, 10) > 8 &&
337			parseInt(this.bitDepth, 10) < 54) {
338			return true;
339			}
340			throw new Error('Invalid bit depth.');
341			}
342			return true;
343			}
344
345			/**
346			* Update the type definition used to read and write the samples.
347			* @private
348			*/
349			updateDataType_() {
350			this.dataType = {
351			bits: ((parseInt(this.bitDepth, 10) - 1) \| 7) + 1,
352			fp: this.bitDepth == '32f' \|\| this.bitDepth == '64',
353			signed: this.bitDepth != '8',
354			be: this.container == 'RIFX'
355			};
356			if (['4', '8a', '8m'].indexOf(this.bitDepth) > -1 ) {
357			this.dataType.bits = 8;
358			this.dataType.signed = false;
359			}
360			}
361
362			/**
363			* Validate the header of the file.
364			* @throws {Error} If bit depth is invalid.
365			* @throws {Error} If the number of channels is invalid.
366			* @throws {Error} If the sample rate is invalid.
367			* @ignore
368			* @private
369			*/
370			validateWavHeader_() {
371			this.validateBitDepth_();
372			if (!validateNumChannels(this.fmt.numChannels, this.fmt.bitsPerSample)) {
373			throw new Error('Invalid number of channels.');
374			}
375			if (!validateSampleRate(
376			this.fmt.numChannels, this.fmt.bitsPerSample, this.fmt.sampleRate)) {
377			throw new Error('Invalid sample rate.');
378			}
379			}
380			}
381

rochars / wavefile

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WaveFileCreator.bitDepthFromFmt_ A

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