| # Copyright (C) 2015 Apple Inc. All rights reserved. |
| # |
| # Redistribution and use in source and binary forms, with or without |
| # modification, are permitted provided that the following conditions |
| # are met: |
| # 1. Redistributions of source code must retain the above copyright |
| # notice, this list of conditions and the following disclaimer. |
| # 2. Redistributions in binary form must reproduce the above copyright |
| # notice, this list of conditions and the following disclaimer in the |
| # documentation and/or other materials provided with the distribution. |
| # |
| # THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND ANY |
| # EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED |
| # WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE |
| # DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY |
| # DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES |
| # (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; |
| # LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON |
| # ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
| # SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| |
| import struct |
| import wave |
| |
| from webkitcorepy import BytesIO, StringIO |
| |
| |
| class WaveDiff(object): |
| _paramNames = ('Number of channels', 'Sample width', 'Sample rate', 'Number of frames', 'Compression type', 'Compression name') |
| |
| # Audio effect processing is intrinsically imprecise, so we need to always allow tolerance. |
| _tolerance = 1 |
| |
| def __init__(self, in1, in2): |
| if isinstance(in1, str): |
| waveFile1 = wave.open(StringIO(in1), 'r') |
| else: |
| waveFile1 = wave.open(BytesIO(in1), 'rb') |
| if isinstance(in2, str): |
| waveFile2 = wave.open(StringIO(in2), 'r') |
| else: |
| waveFile2 = wave.open(BytesIO(in2), 'rb') |
| |
| params1 = waveFile1.getparams() |
| params2 = waveFile2.getparams() |
| |
| self._diff = [] |
| |
| self._filesAreIdentical = not sum(map(self._diffParam, params1, params2, self._paramNames)) |
| self._filesAreIdenticalWithinTolerance = self._filesAreIdentical |
| |
| if not self._filesAreIdentical: |
| return |
| |
| # Metadata is identical, compare the content now. |
| |
| channelCount1 = waveFile1.getnchannels() |
| frameCount1 = waveFile1.getnframes() |
| sampleWidth1 = waveFile1.getsampwidth() |
| channelCount2 = waveFile2.getnchannels() |
| frameCount2 = waveFile2.getnframes() |
| sampleWidth2 = waveFile2.getsampwidth() |
| |
| allData1 = self._readSamples(waveFile1, sampleWidth1, frameCount1 * channelCount1) |
| allData2 = self._readSamples(waveFile2, sampleWidth2, frameCount2 * channelCount2) |
| results = list(map(self._diffSample, allData1, allData2, range(max(frameCount1 * channelCount1, frameCount2 * channelCount2)))) |
| |
| cumulativeSampleDiff = sum(results) |
| differingSampleCount = len(list(filter(bool, results))) |
| self._filesAreIdentical = not differingSampleCount |
| self._filesAreIdenticalWithinTolerance = not len(list(filter(lambda x: x > self._tolerance, results))) |
| |
| if differingSampleCount: |
| self._diff.append('') |
| self._diff.append('Total differing samples: %d' % differingSampleCount) |
| self._diff.append('Percentage of differing samples: %0.3f%%' % (100 * float(differingSampleCount) / max(frameCount1, frameCount2))) |
| self._diff.append('Cumulative sample difference: %d' % cumulativeSampleDiff) |
| self._diff.append('Average sample difference: %f' % (float(cumulativeSampleDiff) / differingSampleCount)) |
| |
| def _diffParam(self, param1, param2, paramName): |
| if param1 == param2: |
| return False |
| self._diff.append(paramName) |
| self._diff.append('< %s' % str(param1)) |
| self._diff.append('---') |
| self._diff.append('> %s' % str(param2)) |
| return True |
| |
| @staticmethod |
| def _readSamples(file, sampleWidth, nSamples): |
| allFrames = file.readframes(nSamples) |
| unpackFormat = 'b' if sampleWidth == 1 else 'h' |
| return struct.unpack('<%d%s' % (nSamples, unpackFormat), allFrames) |
| |
| def _diffSample(self, data1, data2, i): |
| if (data1 != data2): |
| self._diff.append('Sample #%d' % i) |
| self._diff.append('< %d' % data1) |
| self._diff.append('---') |
| self._diff.append('> %d' % data2) |
| return abs(data1 - data2) |
| |
| def filesAreIdentical(self): |
| return self._filesAreIdentical |
| |
| def filesAreIdenticalWithinTolerance(self): |
| return self._filesAreIdenticalWithinTolerance |
| |
| def diffText(self): |
| return '\n'.join(self._diff) |
