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1 // Copyright 2016 The Chromium Authors. All rights reserved. | 1 // Copyright 2016 The Chromium Authors. All rights reserved. |
2 // Use of this source code is governed by a BSD-style license that can be | 2 // Use of this source code is governed by a BSD-style license that can be |
3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
4 | 4 |
5 | 5 |
6 /** | 6 /** |
7 * @fileOverview This file includes legacy utility functions for the layout | 7 * @fileOverview This file includes legacy utility functions for the layout |
8 * test. | 8 * test. |
9 */ | 9 */ |
10 | 10 |
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266 var startFrame = timeToSampleFrame(grainOffset, sampleRate); | 266 var startFrame = timeToSampleFrame(grainOffset, sampleRate); |
267 var endFrame = timeToSampleFrame(grainOffset + duration, sampleRate); | 267 var endFrame = timeToSampleFrame(grainOffset + duration, sampleRate); |
268 | 268 |
269 return endFrame - startFrame; | 269 return endFrame - startFrame; |
270 } | 270 } |
271 | 271 |
272 // True if the number is not an infinity or NaN | 272 // True if the number is not an infinity or NaN |
273 function isValidNumber(x) { | 273 function isValidNumber(x) { |
274 return !isNaN(x) && (x != Infinity) && (x != -Infinity); | 274 return !isNaN(x) && (x != Infinity) && (x != -Infinity); |
275 } | 275 } |
276 | |
277 // Compute the (linear) signal-to-noise ratio between |actual| and | |
278 // |expected|. The result is NOT in dB! If the |actual| and | |
279 // |expected| have different lengths, the shorter length is used. | |
280 function computeSNR(actual, expected) { | |
281 var signalPower = 0; | |
282 var noisePower = 0; | |
283 | |
284 var length = Math.min(actual.length, expected.length); | |
285 | |
286 for (var k = 0; k < length; ++k) { | |
287 var diff = actual[k] - expected[k]; | |
288 signalPower += expected[k] * expected[k]; | |
289 noisePower += diff * diff; | |
290 } | |
291 | |
292 return signalPower / noisePower; | |
293 } | |
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