Issues in index.js - All Issues - Inspection of "fix precision when changing bit depth" - rochars/wavefile - Measure and Improve Code Quality continuously with Scrutinizer

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Push — master ( b3668a...bde98c )

by Rafael S.

created 2017-11-26 15:36 UTC

index.js (10 issues)

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Informational 10

/*!
 * wavefile
 * Read & write wave files with 8, 16, 24, 32 PCM, 32 IEEE & 64-bit data.
 * Copyright (c) 2017 Rafael da Silva Rocha. MIT License.
 * https://github.com/rochars/wavefile
 *
 */

const byteData = require("byte-data");
const wavefileheader = require("./src/wavefileheader");

/**
 * A wave file.
 */
class WaveFile extends wavefileheader.WaveFileHeader {

    /**
     * @param {Uint8Array} bytes The file bytes.
     * @param {boolean} enforceFact True if it should throw a error
     *      if no "fact" chunk is found.
     * @param {boolean} enforceBext True if it should throw a error
     *      if no "bext" chunk is found.
     */
    constructor(bytes, enforceFact=false, enforceBext=false) {
        super();
        /** @type {boolean} */
        this.isFromScratch_ = false;
        /** @type {boolean} */
        this.enforceFact = enforceFact;
        /** @type {boolean} */
        this.enforceBext = enforceBext;
        /**
         * Error messages.
         * @enum {string}
         */
        this.WaveErrors = {
            "format": "Not a supported format.",
            "wave": "Could not find the 'WAVE' chunk",
            "fmt ": "Could not find the 'fmt ' chunk",
            "data": "Could not find the 'data' chunk",
            "fact": "Could not find the 'fact' chunk",
            "bext": "Could not find the 'bext' chunk",
            "bitDepth": "Invalid bit depth.",
            "numChannels": "Invalid number of channels.",
            "sampleRate": "Invalid sample rate."
        };
        this.samples_ = [];
        this.bytes_ = [];
        if(bytes) {
            this.fromBuffer(bytes);
        }
    }

    /**
     * Create a WaveFile object based on the arguments passed.
     * @param {number} numChannels The number of channels
     *     (Ints like 1 for mono, 2 stereo and so on).
     * @param {number} sampleRate The sample rate.
     *     Integer numbers like 8000, 44100, 48000, 96000, 192000.
     * @param {string} bitDepth The audio bit depth.
     *     One of "8", "16", "24", "32", "32f", "64".
     * @param {!Array<number>} samples Array of samples to be written.
     *     Samples must be in the correct range according to the bit depth.
     *     Samples of multi-channel data .
     */
    fromScratch(numChannels, sampleRate, bitDepth, samples, options={}) {
        if (!options.container) {
            options.container = "RIFF";
        }
        this.isFromScratch_ = true;
        let bytes = parseInt(bitDepth, 10) / 8;
        this.chunkSize = 36 + samples.length * bytes;
        this.subChunk1Size = 16;
        this.byteRate = (numChannels * bytes) * sampleRate;
        this.blockAlign = numChannels * bytes;
        this.chunkId = options.container;
        this.format = "WAVE";
        this.subChunk1Id = "fmt ";
        this.audioFormat = this.headerFormats_[bitDepth];
        this.numChannels = numChannels;
        this.sampleRate = sampleRate;
        this.bitsPerSample = parseInt(bitDepth, 10);
        this.subChunk2Id = "data";
        this.subChunk2Size = samples.length * bytes;
        this.samples_ = samples;
        this.bitDepth_ = bitDepth;
    }

    /**
     * Read a wave file from a byte buffer.
     * @param {Uint8Array} bytes The buffer.
     */
    fromBuffer(bytes) {
        this.isFromScratch_ = false;
        this.readRIFFChunk_(bytes);
        this.readWAVEChunk_(bytes);
        this.readFmtChunk_(bytes);
        this.readFactChunk_(bytes);
        this.readBextChunk_(bytes);
        this.readDataChunk_(bytes);
    }

    /**
     * Turn the WaveFile object into a byte buffer.
     * @return {Uint8Array}
     */
    toBuffer() {
        this.checkWriteInput_(this.numChannels, this.sampleRate, this.bitDepth_);
        this.samplesToBytes_();
        return new Uint8Array(this.createWaveFile_());
    }

    /**
     * Turn the file to RIFF.
     * All values will be little-endian when writing.
     */
    toRIFF() {
        this.chunkId = "RIFF";
    }

    /**
     * Turn the file to RIFX.
     * All values but FourCCs will be big-endian when writing.
     */
    toRIFX() {
        this.chunkId = "RIFX";
    }

    /**
     * TODO this should be a external module.
     * Change the bit depth of the data.
     * @param {string} bitDepth The new bit depth of the data.
     *      One of "8", "16", "24", "32", "32f", "64"
     */
    toBitDepth(bitDepth) {
        if (bitDepth == this.bitDepth_) {
            return;
        }
        let originalBitDepth = this.bitDepth_;
        this.bitDepth_ = bitDepth;
        try {
            this.validateBitDepth_();
        } catch(err) {
            this.bitDepth_ = originalBitDepth;
            throw err;
        }
        let len = this.samples_.length;
        let newSamples = [];

        // Get the max values for both original and target bit depth
        let oldMaxValue =
            parseInt((byteData.BitDepthMaxValues[parseInt(originalBitDepth, 10)]) / 2, 10);
        let newMaxValue =
            parseInt((byteData.BitDepthMaxValues[parseInt(this.bitDepth_, 10)]) / 2, 10);

        // needs dithering if the target bit depth
        // is lower than the original bit depth
        if (parseInt(this.bitDepth_, 10) < parseInt(originalBitDepth)) {
            // TODO: dithering
        }

        for (let i=0; i<len;i++) {
            
            // 8-bit samples are unsigned;
            // They are signed here before conversion
            // (other bit depths are all signed)
            if (originalBitDepth == "8") {
                this.samples_[i] -= 128;
            }

            // If it is a float-to-float or int-to-float conversion then
            // the samples in the target bit depth will be normalized in the
            // -1.0 to 1.0 range; there is no need to multiply
            if (this.bitDepth_ == "32f" || this.bitDepth_ == "64") {
                if (originalBitDepth == "32f" || originalBitDepth == "64") {
                    newSamples.push(this.samples_[i]);
                } else {
                    if (this.samples_[i] > 0) {
                        newSamples.push(this.samples_[i] / (oldMaxValue - 1));
                    } else {
                        newSamples.push(this.samples_[i] / oldMaxValue);
                    }
                }

            // If it is a float-to-int or int-to-int conversion then the
            // samples will be de-normalized according to the bit depth
            }else {
                
                // If the original samples are float, then they are already
                // normalized between -1.0 and 1.0; All that is need is to
                // multiply the sample values by the new bit depth max value
                if (originalBitDepth == "32f" || originalBitDepth == "64" ) {
                    if (this.samples_[i] > 0) {
                        newSamples.push((this.samples_[i] * newMaxValue) -1);
                    } else {
                        newSamples.push(this.samples_[i] * newMaxValue);
                    }

                // If the original samples are integers, then they need to be
                // divided by the maximum values of its original bit depth
                // (to normalize them between -1.0 and .10) and then multiply
                // them by the new bit depth max value
                } else {
                    if (this.samples_[i] > 0) {
                        newSamples.push(
                            parseInt((this.samples_[i] / (oldMaxValue - 1)) * newMaxValue - 1, 10)
                        );
                    } else {
                        newSamples.push(
                            parseInt((this.samples_[i] / oldMaxValue) * newMaxValue, 10)
                        );
                    }
                }
                
                // Make the samples unsigned if the target bit depth is "8"
                if (this.bitDepth_ == "8") {
                    newSamples[i] += 128;
                }
            }  
        }
        // recreate the file with the new samples
        // and the new bit depth
        this.fromScratch(
            this.numChannels,
            this.sampleRate,
            this.bitDepth_,
            newSamples,
            {"container": this.chunkId}
        );
    }

    /**
     * Interleave multi-channel samples.
     */
    interleave() {
        let finalSamples = [];
        let i;
        let j;
        let numChannels = this.samples_[0].length;
        for (i = 0; i < numChannels; i++) {
            for (j = 0; j < this.samples_.length; j++) {
                finalSamples.push(this.samples_[j][i]);
            }
        }
        this.samples_ = finalSamples;
    }

    /**
     * De-interleave samples into multiple channels.
     */
    deInterleave() {
        let finalSamples = [];
        let i;
        for (i = 0; i < this.numChannels; i++) {
            finalSamples[i] = [];
        }
        i = 0;
        let j;
        while (i < this.samples_.length) {
            for (j = 0; j < this.numChannels; j++) {
                finalSamples[j].push(this.samples_[i+j]);
            }
            i += j;
        }
        this.samples_ = finalSamples;
    }

    /**
     * Read the RIFF chunk a wave file.
     * @param {Uint8Array} bytes an array representing the wave file.
     * @throws {Error} If no "RIFF" chunk is found.
     */
    readRIFFChunk_(bytes) {
        this.chunkId = byteData.fromBytes(bytes.slice(0, 4),
            8, {"char": true});
        if (this.chunkId != "RIFF" && this.chunkId != "RIFX") {
            throw Error(this.WaveErrors.format);
        }
        this.chunkSize = byteData.fromBytes(
            bytes.slice(4, 8), 32, {"be": this.chunkId == "RIFX"})[0];
    }

    /**
     * Read the WAVE chunk of a wave file.
     * @param {Uint8Array} bytes an array representing the wave file.
     * @throws {Error} If no "WAVE" chunk is found.
     */
    readWAVEChunk_(bytes) {
        let start = byteData.findString(bytes, "WAVE");
        if (start === -1) {
            throw Error(this.WaveErrors.wave);
        }
        this.format = "WAVE";
    }

    /**
     * Read the "fmt " chunk of a wave file.
     * @param {Uint8Array} bytes an array representing the wave file.
     * @throws {Error} If no "fmt " chunk is found.
     */
    readFmtChunk_(bytes) {
        let start = byteData.findString(bytes, "fmt ");
        if (start === -1) {
            throw Error(this.WaveErrors["fmt "]);
        }
        let options = {"be": this.chunkId == "RIFX"};
        this.subChunk1Id = "fmt ";
        this.subChunk1Size = byteData.fromBytes(
            bytes.slice(start + 4, start + 8), 32, options)[0];
        this.audioFormat = byteData.fromBytes(
            bytes.slice(start + 8, start + 10), 16, options)[0];
        this.numChannels = byteData.fromBytes(
            bytes.slice(start + 10, start + 12), 16, options)[0];
        this.sampleRate = byteData.fromBytes(
            bytes.slice(start + 12, start + 16), 32, options)[0];
        this.byteRate = byteData.fromBytes(
            bytes.slice(start + 16, start + 20), 32, options)[0];
        this.blockAlign = byteData.fromBytes(
            bytes.slice(start + 20, start + 22), 16, options)[0];
        this.bitsPerSample = byteData.fromBytes(
            bytes.slice(start + 22, start + 24), 16, options)[0];
        if (this.audioFormat == 3 && this.bitsPerSample == 32) {
            this.bitDepth_ = "32f";
        }else {
            this.bitDepth_ = this.bitsPerSample.toString();
        }
    }

    /**
     * Read the "fact" chunk of a wave file.
     * @param {Uint8Array} bytes an array representing the wave file.
     * @throws {Error} If no "fact" chunk is found.
     */
    readFactChunk_(bytes) {
        let start = byteData.findString(bytes, "fact");
        if (start === -1 && this.enforceFact) {
            throw Error(this.WaveErrors.fact);
        }else if (start > -1) {
            this.factChunkId = "fact";
            //this.factChunkSize = byteData.uIntFrom4Bytes(
            //    bytes.slice(start + 4, start + 8));
            //this.dwSampleLength = byteData.uIntFrom4Bytes(
            //    bytes.slice(start + 8, start + 12));
        }
    }

    /**
     * Read the "bext" chunk of a wave file.
     * @param {Uint8Array} bytes an array representing the wave file.
     * @throws {Error} If no "bext" chunk is found.
     */
    readBextChunk_(bytes) {
        let start = byteData.findString(bytes, "bext");
        if (start === -1 && this.enforceBext) {
            throw Error(this.WaveErrors.bext);
        }else if (start > -1){
            this.bextChunkId = "bext";
        }
    }

    /**
     * Read the "data" chunk of a wave file.
     * @param {Uint8Array} bytes an array representing the wave file.
     * @throws {Error} If no "data" chunk is found.
     */
    readDataChunk_(bytes) {
        let start = byteData.findString(bytes, "data");
        if (start === -1) {
            throw Error(this.WaveErrors.data);
        }
        this.subChunk2Id = "data";
        this.subChunk2Size = byteData.fromBytes(
            bytes.slice(start + 4, start + 8),
            32,
            {"be": this.chunkId == "RIFX"})[0];
        this.samplesFromBytes_(bytes, start);
    }

    /**
     * Find and return the start offset of the data chunk on a wave file.
     * @param {Uint8Array} bytes Array of bytes representing the wave file.
     * @param {number} start The offset to start reading.
     */
    samplesFromBytes_(bytes, start) {
        let params = {
            "signed": this.bitsPerSample == 8 ? false : true,
            "be": this.chunkId == "RIFX"
        };
        if (this.bitsPerSample == 32 && this.audioFormat == 3) {
            params.float = true;
        }
        let samples = bytes.slice(start + 8, start + 8 + this.subChunk2Size);
        if (this.bitsPerSample == 4) {
            this.samples_ = byteData.fromBytes(samples, 8, params);
        } else {
            this.samples_ = byteData.fromBytes(samples, this.bitsPerSample, params);
        }
    }

    /**
     * Validate the input for wav writing.
     * @param {number} numChannels The number of channels

     *     Should be a int greater than zero smaller than the
     *     channel limit according to the bit depth.
     * @param {number} sampleRate The sample rate.

     *     Should be a int greater than zero smaller than the
     *     channel limit according to the bit depth and number of channels.
     * @param {string} bitDepth The audio bit depth.

     *     Should be one of "8", "16", "24", "32", "32f", "64".
     * @throws {Error} If any argument does not meet the criteria.
     */
    checkWriteInput_() {
        this.validateBitDepth_();
        this.validateNumChannels_();
        this.validateSampleRate_();
    }

    /**
     * Validate the bit depth.
     * @param {number} numChannels The number of channels

     * @param {string} bitDepth The audio bit depth.

     *     Should be one of "8", "16", "24", "32", "32f", "64".
     * @throws {Error} If any argument does not meet the criteria.
     */
    validateBitDepth_() {
        if (!this.headerFormats_[this.bitDepth_]) {
            throw new Error(this.WaveErrors.bitDepth);
        }
        return true;
    }

    /**
     * Validate the sample rate value.
     * @param {number} numChannels The number of channels

     * @param {string} bitDepth The audio bit depth.

     *     Should be one of "8", "16", "24", "32", "32f", "64".
     * @throws {Error} If any argument does not meet the criteria.
     */
    validateNumChannels_() {
        let blockAlign = this.numChannels * this.bitsPerSample / 8;
        if (this.numChannels < 1 || blockAlign > 65535) {
            throw new Error(this.WaveErrors.numChannels);
        }
        return true;
    }

    /**
     * Validate the sample rate value.
     * @param {number} numChannels The number of channels

     *     Should be a int greater than zero smaller than the
     *     channel limit according to the bit depth.
     * @param {number} sampleRate The sample rate.

     * @param {string} bitDepth The audio bit depth.

     *     Should be one of "8", "16", "24", "32", "32f", "64".
     * @throws {Error} If any argument does not meet the criteria.
     */
    validateSampleRate_() {
        let byteRate = this.numChannels *
            (this.bitsPerSample / 8) * this.sampleRate;
        if (this.sampleRate < 1 || byteRate > 4294967295) {
            throw new Error(this.WaveErrors.sampleRate);
        }
        return true;
    }

    /**
     * Split each sample into bytes.
     */
    samplesToBytes_() {
        let params = {"be": this.chunkId == "RIFX"};
        if (this.bitsPerSample == 32 && this.audioFormat == 3) {
            params.float = true;
        }
        let bitDepth = this.bitsPerSample == 4 ? 8 : this.bitsPerSample;
        this.bytes_ = byteData.toBytes(this.samples_, bitDepth, params);
        if (this.bytes_.length % 2) {
            this.bytes_.push(0);
        }
    }

    /**
     * Turn a WaveFile object into a file.
     * @return {Uint8Array} The wav file bytes.
     */
    createWaveFile_() {
        let factVal = [];
        if (this.factChunkId) {
            factVal = byteData.toBytes(this.factChunkId, 8, {"char": true});
        }
        let options = {"be": this.chunkId == "RIFX"};
        return byteData.toBytes(this.chunkId, 8, {"char": true}).concat(
            byteData.toBytes([this.chunkSize], 32, options),
            byteData.toBytes(this.format, 8, {"char": true}), 
            byteData.toBytes(this.subChunk1Id, 8, {"char": true}),
            byteData.toBytes([this.subChunk1Size], 32, options),
            byteData.toBytes([this.audioFormat], 16, options),
            byteData.toBytes([this.numChannels], 16, options),
            byteData.toBytes([this.sampleRate], 32, options),
            byteData.toBytes([this.byteRate], 32, options),
            byteData.toBytes([this.blockAlign], 16, options),
            byteData.toBytes([this.bitsPerSample], 16, options),
            factVal,
            byteData.toBytes(this.subChunk2Id, 8, {"char": true}),
            byteData.toBytes([this.subChunk2Size], 32, options),
            this.bytes_);
    }
}

module.exports.WaveFile = WaveFile;


1			/*!
2			* wavefile
3			* Read & write wave files with 8, 16, 24, 32 PCM, 32 IEEE & 64-bit data.
4			* Copyright (c) 2017 Rafael da Silva Rocha. MIT License.
5			* https://github.com/rochars/wavefile
6			*
7			*/
8
9			const byteData = require("byte-data");
10			const wavefileheader = require("./src/wavefileheader");
11
12			/**
13			* A wave file.
14			*/
15			class WaveFile extends wavefileheader.WaveFileHeader {
16
17			/**
18			* @param {Uint8Array} bytes The file bytes.
19			* @param {boolean} enforceFact True if it should throw a error
20			* if no "fact" chunk is found.
21			* @param {boolean} enforceBext True if it should throw a error
22			* if no "bext" chunk is found.
23			*/
24			constructor(bytes, enforceFact=false, enforceBext=false) {
25			super();
26			/** @type {boolean} */
27			this.isFromScratch_ = false;
28			/** @type {boolean} */
29			this.enforceFact = enforceFact;
30			/** @type {boolean} */
31			this.enforceBext = enforceBext;
32			/**
33			* Error messages.
34			* @enum {string}
35			*/
36			this.WaveErrors = {
37			"format": "Not a supported format.",
38			"wave": "Could not find the 'WAVE' chunk",
39			"fmt ": "Could not find the 'fmt ' chunk",
40			"data": "Could not find the 'data' chunk",
41			"fact": "Could not find the 'fact' chunk",
42			"bext": "Could not find the 'bext' chunk",
43			"bitDepth": "Invalid bit depth.",
44			"numChannels": "Invalid number of channels.",
45			"sampleRate": "Invalid sample rate."
46			};
47			this.samples_ = [];
48			this.bytes_ = [];
49			if(bytes) {
50			this.fromBuffer(bytes);
51			}
52			}
53
54			/**
55			* Create a WaveFile object based on the arguments passed.
56			* @param {number} numChannels The number of channels
57			* (Ints like 1 for mono, 2 stereo and so on).
58			* @param {number} sampleRate The sample rate.
59			* Integer numbers like 8000, 44100, 48000, 96000, 192000.
60			* @param {string} bitDepth The audio bit depth.
61			* One of "8", "16", "24", "32", "32f", "64".
62			* @param {!Array<number>} samples Array of samples to be written.
63			* Samples must be in the correct range according to the bit depth.
64			* Samples of multi-channel data .
65			*/
66			fromScratch(numChannels, sampleRate, bitDepth, samples, options={}) {
67			if (!options.container) {
68			options.container = "RIFF";
69			}
70			this.isFromScratch_ = true;
71			let bytes = parseInt(bitDepth, 10) / 8;
72			this.chunkSize = 36 + samples.length * bytes;
73			this.subChunk1Size = 16;
74			this.byteRate = (numChannels * bytes) * sampleRate;
75			this.blockAlign = numChannels * bytes;
76			this.chunkId = options.container;
77			this.format = "WAVE";
78			this.subChunk1Id = "fmt ";
79			this.audioFormat = this.headerFormats_[bitDepth];
80			this.numChannels = numChannels;
81			this.sampleRate = sampleRate;
82			this.bitsPerSample = parseInt(bitDepth, 10);
83			this.subChunk2Id = "data";
84			this.subChunk2Size = samples.length * bytes;
85			this.samples_ = samples;
86			this.bitDepth_ = bitDepth;
87			}
88
89			/**
90			* Read a wave file from a byte buffer.
91			* @param {Uint8Array} bytes The buffer.
92			*/
93			fromBuffer(bytes) {
94			this.isFromScratch_ = false;
95			this.readRIFFChunk_(bytes);
96			this.readWAVEChunk_(bytes);
97			this.readFmtChunk_(bytes);
98			this.readFactChunk_(bytes);
99			this.readBextChunk_(bytes);
100			this.readDataChunk_(bytes);
101			}
102
103			/**
104			* Turn the WaveFile object into a byte buffer.
105			* @return {Uint8Array}
106			*/
107			toBuffer() {
108			this.checkWriteInput_(this.numChannels, this.sampleRate, this.bitDepth_);
109			this.samplesToBytes_();
110			return new Uint8Array(this.createWaveFile_());
111			}
112
113			/**
114			* Turn the file to RIFF.
115			* All values will be little-endian when writing.
116			*/
117			toRIFF() {
118			this.chunkId = "RIFF";
119			}
120
121			/**
122			* Turn the file to RIFX.
123			* All values but FourCCs will be big-endian when writing.
124			*/
125			toRIFX() {
126			this.chunkId = "RIFX";
127			}
128
129			/**
130			* TODO this should be a external module.
131			* Change the bit depth of the data.
132			* @param {string} bitDepth The new bit depth of the data.
133			* One of "8", "16", "24", "32", "32f", "64"
134			*/
135			toBitDepth(bitDepth) {
136			if (bitDepth == this.bitDepth_) {
137			return;
138			}
139			let originalBitDepth = this.bitDepth_;
140			this.bitDepth_ = bitDepth;
141			try {
142			this.validateBitDepth_();
143			} catch(err) {
144			this.bitDepth_ = originalBitDepth;
145			throw err;
146			}
147			let len = this.samples_.length;
148			let newSamples = [];
149
150			// Get the max values for both original and target bit depth
151			let oldMaxValue =
152			parseInt((byteData.BitDepthMaxValues[parseInt(originalBitDepth, 10)]) / 2, 10);
153			let newMaxValue =
154			parseInt((byteData.BitDepthMaxValues[parseInt(this.bitDepth_, 10)]) / 2, 10);
155
156			// needs dithering if the target bit depth
157			// is lower than the original bit depth
158			if (parseInt(this.bitDepth_, 10) < parseInt(originalBitDepth)) {
159			// TODO: dithering
160			}
161
162			for (let i=0; i<len;i++) {
163
164			// 8-bit samples are unsigned;
165			// They are signed here before conversion
166			// (other bit depths are all signed)
167			if (originalBitDepth == "8") {
168			this.samples_[i] -= 128;
169			}
170
171			// If it is a float-to-float or int-to-float conversion then
172			// the samples in the target bit depth will be normalized in the
173			// -1.0 to 1.0 range; there is no need to multiply
174			if (this.bitDepth_ == "32f" \|\| this.bitDepth_ == "64") {
175			if (originalBitDepth == "32f" \|\| originalBitDepth == "64") {
176			newSamples.push(this.samples_[i]);
177			} else {
178			if (this.samples_[i] > 0) {
179			newSamples.push(this.samples_[i] / (oldMaxValue - 1));
180			} else {
181			newSamples.push(this.samples_[i] / oldMaxValue);
182			}
183			}
184
185			// If it is a float-to-int or int-to-int conversion then the
186			// samples will be de-normalized according to the bit depth
187			}else {
188
189			// If the original samples are float, then they are already
190			// normalized between -1.0 and 1.0; All that is need is to
191			// multiply the sample values by the new bit depth max value
192			if (originalBitDepth == "32f" \|\| originalBitDepth == "64" ) {
193			if (this.samples_[i] > 0) {
194			newSamples.push((this.samples_[i] * newMaxValue) -1);
195			} else {
196			newSamples.push(this.samples_[i] * newMaxValue);
197			}
198
199			// If the original samples are integers, then they need to be
200			// divided by the maximum values of its original bit depth
201			// (to normalize them between -1.0 and .10) and then multiply
202			// them by the new bit depth max value
203			} else {
204			if (this.samples_[i] > 0) {
205			newSamples.push(
206			parseInt((this.samples_[i] / (oldMaxValue - 1)) * newMaxValue - 1, 10)
207			);
208			} else {
209			newSamples.push(
210			parseInt((this.samples_[i] / oldMaxValue) * newMaxValue, 10)
211			);
212			}
213			}
214
215			// Make the samples unsigned if the target bit depth is "8"
216			if (this.bitDepth_ == "8") {
217			newSamples[i] += 128;
218			}
219			}
220			}
221			// recreate the file with the new samples
222			// and the new bit depth
223			this.fromScratch(
224			this.numChannels,
225			this.sampleRate,
226			this.bitDepth_,
227			newSamples,
228			{"container": this.chunkId}
229			);
230			}
231
232			/**
233			* Interleave multi-channel samples.
234			*/
235			interleave() {
236			let finalSamples = [];
237			let i;
238			let j;
239			let numChannels = this.samples_[0].length;
240			for (i = 0; i < numChannels; i++) {
241			for (j = 0; j < this.samples_.length; j++) {
242			finalSamples.push(this.samples_[j][i]);
243			}
244			}
245			this.samples_ = finalSamples;
246			}
247
248			/**
249			* De-interleave samples into multiple channels.
250			*/
251			deInterleave() {
252			let finalSamples = [];
253			let i;
254			for (i = 0; i < this.numChannels; i++) {
255			finalSamples[i] = [];
256			}
257			i = 0;
258			let j;
259			while (i < this.samples_.length) {
260			for (j = 0; j < this.numChannels; j++) {
261			finalSamples[j].push(this.samples_[i+j]);
262			}
263			i += j;
264			}
265			this.samples_ = finalSamples;
266			}
267
268			/**
269			* Read the RIFF chunk a wave file.
270			* @param {Uint8Array} bytes an array representing the wave file.
271			* @throws {Error} If no "RIFF" chunk is found.
272			*/
273			readRIFFChunk_(bytes) {
274			this.chunkId = byteData.fromBytes(bytes.slice(0, 4),
275			8, {"char": true});
276			if (this.chunkId != "RIFF" && this.chunkId != "RIFX") {
277			throw Error(this.WaveErrors.format);
278			}
279			this.chunkSize = byteData.fromBytes(
280			bytes.slice(4, 8), 32, {"be": this.chunkId == "RIFX"})[0];
281			}
282
283			/**
284			* Read the WAVE chunk of a wave file.
285			* @param {Uint8Array} bytes an array representing the wave file.
286			* @throws {Error} If no "WAVE" chunk is found.
287			*/
288			readWAVEChunk_(bytes) {
289			let start = byteData.findString(bytes, "WAVE");
290			if (start === -1) {
291			throw Error(this.WaveErrors.wave);
292			}
293			this.format = "WAVE";
294			}
295
296			/**
297			* Read the "fmt " chunk of a wave file.
298			* @param {Uint8Array} bytes an array representing the wave file.
299			* @throws {Error} If no "fmt " chunk is found.
300			*/
301			readFmtChunk_(bytes) {
302			let start = byteData.findString(bytes, "fmt ");
303			if (start === -1) {
304			throw Error(this.WaveErrors["fmt "]);
305			}
306			let options = {"be": this.chunkId == "RIFX"};
307			this.subChunk1Id = "fmt ";
308			this.subChunk1Size = byteData.fromBytes(
309			bytes.slice(start + 4, start + 8), 32, options)[0];
310			this.audioFormat = byteData.fromBytes(
311			bytes.slice(start + 8, start + 10), 16, options)[0];
312			this.numChannels = byteData.fromBytes(
313			bytes.slice(start + 10, start + 12), 16, options)[0];
314			this.sampleRate = byteData.fromBytes(
315			bytes.slice(start + 12, start + 16), 32, options)[0];
316			this.byteRate = byteData.fromBytes(
317			bytes.slice(start + 16, start + 20), 32, options)[0];
318			this.blockAlign = byteData.fromBytes(
319			bytes.slice(start + 20, start + 22), 16, options)[0];
320			this.bitsPerSample = byteData.fromBytes(
321			bytes.slice(start + 22, start + 24), 16, options)[0];
322			if (this.audioFormat == 3 && this.bitsPerSample == 32) {
323			this.bitDepth_ = "32f";
324			}else {
325			this.bitDepth_ = this.bitsPerSample.toString();
326			}
327			}
328
329			/**
330			* Read the "fact" chunk of a wave file.
331			* @param {Uint8Array} bytes an array representing the wave file.
332			* @throws {Error} If no "fact" chunk is found.
333			*/
334			readFactChunk_(bytes) {
335			let start = byteData.findString(bytes, "fact");
336			if (start === -1 && this.enforceFact) {
337			throw Error(this.WaveErrors.fact);
338			}else if (start > -1) {
339			this.factChunkId = "fact";
340			//this.factChunkSize = byteData.uIntFrom4Bytes(
341			// bytes.slice(start + 4, start + 8));
342			//this.dwSampleLength = byteData.uIntFrom4Bytes(
343			// bytes.slice(start + 8, start + 12));
344			}
345			}
346
347			/**
348			* Read the "bext" chunk of a wave file.
349			* @param {Uint8Array} bytes an array representing the wave file.
350			* @throws {Error} If no "bext" chunk is found.
351			*/
352			readBextChunk_(bytes) {
353			let start = byteData.findString(bytes, "bext");
354			if (start === -1 && this.enforceBext) {
355			throw Error(this.WaveErrors.bext);
356			}else if (start > -1){
357			this.bextChunkId = "bext";
358			}
359			}
360
361			/**
362			* Read the "data" chunk of a wave file.
363			* @param {Uint8Array} bytes an array representing the wave file.
364			* @throws {Error} If no "data" chunk is found.
365			*/
366			readDataChunk_(bytes) {
367			let start = byteData.findString(bytes, "data");
368			if (start === -1) {
369			throw Error(this.WaveErrors.data);
370			}
371			this.subChunk2Id = "data";
372			this.subChunk2Size = byteData.fromBytes(
373			bytes.slice(start + 4, start + 8),
374			32,
375			{"be": this.chunkId == "RIFX"})[0];
376			this.samplesFromBytes_(bytes, start);
377			}
378
379			/**
380			* Find and return the start offset of the data chunk on a wave file.
381			* @param {Uint8Array} bytes Array of bytes representing the wave file.
382			* @param {number} start The offset to start reading.
383			*/
384			samplesFromBytes_(bytes, start) {
385			let params = {
386			"signed": this.bitsPerSample == 8 ? false : true,
387			"be": this.chunkId == "RIFX"
388			};
389			if (this.bitsPerSample == 32 && this.audioFormat == 3) {
390			params.float = true;
391			}
392			let samples = bytes.slice(start + 8, start + 8 + this.subChunk2Size);
393			if (this.bitsPerSample == 4) {
394			this.samples_ = byteData.fromBytes(samples, 8, params);
395			} else {
396			this.samples_ = byteData.fromBytes(samples, this.bitsPerSample, params);
397			}
398			}
399
400			/**
401			* Validate the input for wav writing.
402			* @param {number} numChannels The number of channels
			0 ignored issues – show Documentation introduced 2017-11-24 03:03 UTC by Report Bug Copy Issue Report Show Similar Issues like this The parameter `numChannels` does not exist. Did you maybe forget to remove this comment? Loading history...
403			* Should be a int greater than zero smaller than the
404			* channel limit according to the bit depth.
405			* @param {number} sampleRate The sample rate.
			0 ignored issues – show Documentation introduced 2017-11-24 03:03 UTC by Report Bug Copy Issue Report Show Similar Issues like this The parameter `sampleRate` does not exist. Did you maybe forget to remove this comment? Loading history...
406			* Should be a int greater than zero smaller than the
407			* channel limit according to the bit depth and number of channels.
408			* @param {string} bitDepth The audio bit depth.
			0 ignored issues – show Documentation introduced 2017-11-24 03:03 UTC by Report Bug Copy Issue Report Show Similar Issues like this The parameter `bitDepth` does not exist. Did you maybe forget to remove this comment? Loading history...
409			* Should be one of "8", "16", "24", "32", "32f", "64".
410			* @throws {Error} If any argument does not meet the criteria.
411			*/
412			checkWriteInput_() {
413			this.validateBitDepth_();
414			this.validateNumChannels_();
415			this.validateSampleRate_();
416			}
417
418			/**
419			* Validate the bit depth.
420			* @param {number} numChannels The number of channels
			0 ignored issues – show Documentation introduced 2017-11-24 03:03 UTC by Report Bug Copy Issue Report Show Similar Issues like this The parameter `numChannels` does not exist. Did you maybe forget to remove this comment? Loading history...
421			* @param {string} bitDepth The audio bit depth.
			0 ignored issues – show Documentation introduced 2017-11-24 03:03 UTC by Report Bug Copy Issue Report Show Similar Issues like this The parameter `bitDepth` does not exist. Did you maybe forget to remove this comment? Loading history...
422			* Should be one of "8", "16", "24", "32", "32f", "64".
423			* @throws {Error} If any argument does not meet the criteria.
424			*/
425			validateBitDepth_() {
426			if (!this.headerFormats_[this.bitDepth_]) {
427			throw new Error(this.WaveErrors.bitDepth);
428			}
429			return true;
430			}
431
432			/**
433			* Validate the sample rate value.
434			* @param {number} numChannels The number of channels
			0 ignored issues – show Documentation introduced 2017-11-26 05:11 UTC by Report Bug Copy Issue Report Show Similar Issues like this The parameter `numChannels` does not exist. Did you maybe forget to remove this comment? Loading history...
435			* @param {string} bitDepth The audio bit depth.
			0 ignored issues – show Documentation introduced 2017-11-26 05:11 UTC by Report Bug Copy Issue Report Show Similar Issues like this The parameter `bitDepth` does not exist. Did you maybe forget to remove this comment? Loading history...
436			* Should be one of "8", "16", "24", "32", "32f", "64".
437			* @throws {Error} If any argument does not meet the criteria.
438			*/
439			validateNumChannels_() {
440			let blockAlign = this.numChannels * this.bitsPerSample / 8;
441			if (this.numChannels < 1 \|\| blockAlign > 65535) {
442			throw new Error(this.WaveErrors.numChannels);
443			}
444			return true;
445			}
446
447			/**
448			* Validate the sample rate value.
449			* @param {number} numChannels The number of channels
			0 ignored issues – show Documentation introduced 2017-11-24 03:03 UTC by Report Bug Copy Issue Report Show Similar Issues like this The parameter `numChannels` does not exist. Did you maybe forget to remove this comment? Loading history...
450			* Should be a int greater than zero smaller than the
451			* channel limit according to the bit depth.
452			* @param {number} sampleRate The sample rate.
			0 ignored issues – show Documentation introduced 2017-11-24 03:03 UTC by Report Bug Copy Issue Report Show Similar Issues like this The parameter `sampleRate` does not exist. Did you maybe forget to remove this comment? Loading history...
453			* @param {string} bitDepth The audio bit depth.
			0 ignored issues – show Documentation introduced 2017-11-24 03:03 UTC by Report Bug Copy Issue Report Show Similar Issues like this The parameter `bitDepth` does not exist. Did you maybe forget to remove this comment? Loading history...
454			* Should be one of "8", "16", "24", "32", "32f", "64".
455			* @throws {Error} If any argument does not meet the criteria.
456			*/
457			validateSampleRate_() {
458			let byteRate = this.numChannels *
459			(this.bitsPerSample / 8) * this.sampleRate;
460			if (this.sampleRate < 1 \|\| byteRate > 4294967295) {
461			throw new Error(this.WaveErrors.sampleRate);
462			}
463			return true;
464			}
465
466			/**
467			* Split each sample into bytes.
468			*/
469			samplesToBytes_() {
470			let params = {"be": this.chunkId == "RIFX"};
471			if (this.bitsPerSample == 32 && this.audioFormat == 3) {
472			params.float = true;
473			}
474			let bitDepth = this.bitsPerSample == 4 ? 8 : this.bitsPerSample;
475			this.bytes_ = byteData.toBytes(this.samples_, bitDepth, params);
476			if (this.bytes_.length % 2) {
477			this.bytes_.push(0);
478			}
479			}
480
481			/**
482			* Turn a WaveFile object into a file.
483			* @return {Uint8Array} The wav file bytes.
484			*/
485			createWaveFile_() {
486			let factVal = [];
487			if (this.factChunkId) {
488			factVal = byteData.toBytes(this.factChunkId, 8, {"char": true});
489			}
490			let options = {"be": this.chunkId == "RIFX"};
491			return byteData.toBytes(this.chunkId, 8, {"char": true}).concat(
492			byteData.toBytes([this.chunkSize], 32, options),
493			byteData.toBytes(this.format, 8, {"char": true}),
494			byteData.toBytes(this.subChunk1Id, 8, {"char": true}),
495			byteData.toBytes([this.subChunk1Size], 32, options),
496			byteData.toBytes([this.audioFormat], 16, options),
497			byteData.toBytes([this.numChannels], 16, options),
498			byteData.toBytes([this.sampleRate], 32, options),
499			byteData.toBytes([this.byteRate], 32, options),
500			byteData.toBytes([this.blockAlign], 16, options),
501			byteData.toBytes([this.bitsPerSample], 16, options),
502			factVal,
503			byteData.toBytes(this.subChunk2Id, 8, {"char": true}),
504			byteData.toBytes([this.subChunk2Size], 32, options),
505			this.bytes_);
506			}
507			}
508
509			module.exports.WaveFile = WaveFile;
510

rochars / wavefile

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