| <!DOCTYPE HTML> |
| <html> |
| <head> |
| <script src="../resources/js-test.js"></script> |
| <script src="resources/compatibility.js"></script> |
| <script type="text/javascript" src="resources/audio-testing.js"></script> |
| </head> |
| |
| <body> |
| <div id="description"></div> |
| <div id="console"></div> |
| |
| <script> |
| description("Test pre-emphasis in DynamicsCompressor is removed"); |
| var context; |
| var sampleRate = 44100; |
| var lengthInSeconds = 1; |
| var renderedData; |
| // This threshold experimentally determined. It depends on the the gain value of the gain node |
| // below and the dynamics compressor. When the DynamicsCompressor had the pre-emphasis |
| // filters, the peak value is about 0.21. Without it, the peak is about 0.84. |
| var peakThreshold = 0.83; |
| |
| function checkResult(event) { |
| var renderedBuffer = event.renderedBuffer; |
| renderedData = renderedBuffer.getChannelData(0); |
| // Search for a peak in the last part of the data. |
| var startSample = sampleRate * (lengthInSeconds - .1); |
| var endSample = renderedData.length; |
| var k; |
| var peak = -1; |
| |
| for (k = startSample; k < endSample; ++k) { |
| var sample = Math.abs(renderedData[k]); |
| if (peak < sample) |
| peak = sample; |
| } |
| |
| if (peak >= peakThreshold) { |
| testPassed("Pre-emphasis effect not applied as expected.."); |
| } else { |
| testFailed("Pre-emphasis caused output to be decreased to " + peak |
| + " (expected >= " + peakThreshold + ")"); |
| } |
| |
| finishJSTest(); |
| } |
| |
| function runTest() { |
| if (!window.testRunner) { |
| testRunner.dumpAsTest(); |
| testRunner.waitUntilDone(); |
| } |
| |
| window.jsTestIsAsync = true; |
| |
| context = new OfflineAudioContext(1, sampleRate * lengthInSeconds, sampleRate); |
| // Connect an oscillator to a gain node to the compressor. The |
| // oscillator frequency is set to a high value for the (original) |
| // emphasis to kick in. The gain is a little extra boost to get the |
| // compressor enabled. |
| // |
| var osc = context.createOscillator(); |
| osc.frequency.value = 15000; |
| var gain = context.createGain(); |
| gain.gain.value = 1.5; |
| var compressor = context.createDynamicsCompressor(); |
| osc.connect(gain); |
| gain.connect(compressor); |
| compressor.connect(context.destination); |
| osc.start(); |
| context.oncomplete = checkResult; |
| context.startRendering(); |
| } |
| |
| runTest(); |
| successfullyParsed = true; |
| |
| </script> |
| |
| </body> |
| </html> |
