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/* |
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* Copyright (c) 2017-2019 Rafael da Silva Rocha. |
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* |
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* Permission is hereby granted, free of charge, to any person obtaining |
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* a copy of this software and associated documentation files (the |
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* "Software"), to deal in the Software without restriction, including |
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* without limitation the rights to use, copy, modify, merge, publish, |
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* distribute, sublicense, and/or sell copies of the Software, and to |
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* permit persons to whom the Software is furnished to do so, subject to |
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* the following conditions: |
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* |
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* The above copyright notice and this permission notice shall be |
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* included in all copies or substantial portions of the Software. |
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* |
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, |
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF |
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND |
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE |
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* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION |
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* OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION |
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* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. |
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* |
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*/ |
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/** |
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* @fileoverview The dwChannelMask function. |
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* @see https://github.com/rochars/wavefile |
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*/ |
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/** |
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* Return the value for dwChannelMask according to the number of channels. |
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* @param {number} numChannels the number of channels. |
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* @return {number} the dwChannelMask value. |
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* @private |
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*/ |
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export default function dwChannelMask(numChannels) { |
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/** @type {number} */ |
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let dwChannelMask = 0; |
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// mono = FC |
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if (numChannels === 1) { |
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dwChannelMask = 0x4; |
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// stereo = FL, FR |
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} else if (numChannels === 2) { |
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dwChannelMask = 0x3; |
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// quad = FL, FR, BL, BR |
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} else if (numChannels === 4) { |
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dwChannelMask = 0x33; |
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// 5.1 = FL, FR, FC, LF, BL, BR |
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} else if (numChannels === 6) { |
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dwChannelMask = 0x3F; |
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// 7.1 = FL, FR, FC, LF, BL, BR, SL, SR |
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} else if (numChannels === 8) { |
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dwChannelMask = 0x63F; |
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} |
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return dwChannelMask; |
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} |
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