| <!doctype html> |
| <html> |
| <head> |
| <title>Test ScriptProcessorNode</title> |
| <script src="/resources/testharness.js"></script> |
| <script src="/resources/testharnessreport.js"></script> |
| <script src="/webaudio/resources/audit-util.js"></script> |
| <script src="/webaudio/resources/audit.js"></script> |
| </head> |
| |
| <body> |
| <script> |
| // Arbitrary sample rate |
| const sampleRate = 48000; |
| let audit = Audit.createTaskRunner(); |
| |
| audit.define( |
| { |
| label: 'test', |
| description: 'ScriptProcessor with stopped input source' |
| }, |
| (task, should) => { |
| // Two channels for testing. Channel 0 is the output of the |
| // scriptProcessor. Channel 1 is the oscillator so we can compare |
| // the outputs. |
| let context = new OfflineAudioContext({ |
| numberOfChannels: 2, |
| length: sampleRate, |
| sampleRate: sampleRate |
| }); |
| |
| let merger = new ChannelMergerNode( |
| context, {numberOfChannels: context.destination.channelCount}); |
| merger.connect(context.destination); |
| |
| let src = new OscillatorNode(context); |
| |
| // Arbitrary buffer size for the ScriptProcessorNode. Don't use 0; |
| // we need to know the actual size to know the latency of the node |
| // (easily). |
| const spnSize = 512; |
| let spn = context.createScriptProcessor(spnSize, 1, 1); |
| |
| // Arrange for the ScriptProcessor to add |offset| to the input. |
| const offset = 1; |
| spn.onaudioprocess = (event) => { |
| let input = event.inputBuffer.getChannelData(0); |
| let output = event.outputBuffer.getChannelData(0); |
| for (let k = 0; k < output.length; ++k) { |
| output[k] = input[k] + offset; |
| } |
| }; |
| |
| src.connect(spn).connect(merger, 0, 0); |
| src.connect(merger, 0, 1); |
| |
| // Start and stop the source. The stop time is fairly arbitrary, |
| // but use a render quantum boundary for simplicity. |
| const stopFrame = RENDER_QUANTUM_FRAMES; |
| src.start(0); |
| src.stop(stopFrame / context.sampleRate); |
| |
| context.startRendering() |
| .then(buffer => { |
| let ch0 = buffer.getChannelData(0); |
| let ch1 = buffer.getChannelData(1); |
| |
| let shifted = ch1.slice(0, stopFrame).map(x => x + offset); |
| |
| // SPN has a basic latency of 2*|spnSize| fraems, so the |
| // beginning is silent. |
| should( |
| ch0.slice(0, 2 * spnSize - 1), |
| `ScriptProcessor output[0:${2 * spnSize - 1}]`) |
| .beConstantValueOf(0); |
| |
| // For the middle section (after adding latency), the output |
| // should be the source shifted by |offset|. |
| should( |
| ch0.slice(2 * spnSize, 2 * spnSize + stopFrame), |
| `ScriptProcessor output[${2 * spnSize}:${ |
| 2 * spnSize + stopFrame - 1}]`) |
| .beCloseToArray(shifted, {absoluteThreshold: 0}); |
| |
| // Output should be constant after the source has stopped. |
| // Include the latency introduced by the node. |
| should( |
| ch0.slice(2 * spnSize + stopFrame), |
| `ScriptProcessor output[${2 * spnSize + stopFrame}:]`) |
| .beConstantValueOf(offset); |
| }) |
| .then(() => task.done()); |
| }); |
| |
| audit.run(); |
| </script> |
| </body> |
| </html> |
