| <!DOCTYPE html> |
| |
| <!-- |
| Tests that that we can merge two mono streams into a stereo stream. |
| --> |
| |
| <html> |
| <head> |
| <script src="../resources/js-test.js"></script> |
| <script type="text/javascript" src="resources/audio-testing.js"></script> |
| <script type="text/javascript" src="resources/buffer-loader.js"></script> |
| </head> |
| |
| <body> |
| |
| <div id="description"></div> |
| <div id="console"></div> |
| |
| <script> |
| description("Tests audio channel merging of two mono streams into a single stereo stream."); |
| |
| var sampleRate = 44100.0; |
| var lengthInSampleFrames = 512; |
| |
| var context = 0; |
| var bufferLoader = 0; |
| var buffer1; |
| var buffer2; |
| var bufferSource1; |
| var bufferSource2; |
| var channelMerger; |
| |
| function createBufferWithDCOffset(length, sampleRate, offset) { |
| var buffer = context.createBuffer(1, length, sampleRate); |
| var data = buffer.getChannelData(0); |
| for (var i = 0; i < buffer.length; ++i) |
| data[i] = offset; |
| |
| return buffer; |
| } |
| |
| // checkResult() checks that the rendered buffer is stereo and that the left channel is all -1 and right channel all +1. |
| function checkResult(event) { |
| var buffer = event.renderedBuffer; |
| |
| var success = true; |
| |
| if (buffer.numberOfChannels == 2) { |
| var bufferDataL = buffer.getChannelData(0); |
| var bufferDataR = buffer.getChannelData(1); |
| |
| // Go through every sample and make sure it's all -1 for the left-channel, and all +1 for the right-channel. |
| for (var i = 0; i < buffer.length; ++i) { |
| if (bufferDataL[i] != -1 || bufferDataR[i] != 1) { |
| success = false; |
| break; |
| } |
| } |
| } else { |
| success = false; |
| } |
| |
| if (success) { |
| testPassed("Correctly merged from two mono streams to stereo."); |
| } else { |
| testFailed("Merging error from two mono streams to stereo."); |
| } |
| |
| finishJSTest(); |
| } |
| |
| function runTest() { |
| window.jsTestIsAsync = true; |
| |
| // Create stereo offline audio context. |
| context = new OfflineAudioContext(2, lengthInSampleFrames, sampleRate); |
| |
| // Create two mono buffers, one having all -1 values, the other all +1. |
| buffer1 = createBufferWithDCOffset(lengthInSampleFrames, sampleRate, -1); |
| buffer2 = createBufferWithDCOffset(lengthInSampleFrames, sampleRate, 1); |
| |
| // Create a buffer source for each of these buffers. |
| bufferSource1 = context.createBufferSource(); |
| bufferSource2 = context.createBufferSource(); |
| bufferSource1.buffer = buffer1; |
| bufferSource2.buffer = buffer2; |
| |
| // Create a channel merger and connect it so that it merges two mono streams into a single stereo stream. |
| |
| channelMerger = context.createChannelMerger(); |
| bufferSource1.connect(channelMerger, 0, 0); // connect to input 0 of the channel merger |
| bufferSource2.connect(channelMerger, 0, 1); // connect to input 1 of the channel merger |
| |
| channelMerger.connect(context.destination); |
| |
| // Trigger both sources to start at the beginning. |
| bufferSource1.start(0); |
| bufferSource2.start(0); |
| |
| context.oncomplete = checkResult; |
| context.startRendering(); |
| } |
| |
| runTest(); |
| |
| </script> |
| </body> |
| </html> |
