添加音调升降调节

2023-05-31 21:40:25 +08:00
parent 677c3f16e4
commit 40997c34ff
21 changed files with 1435 additions and 20 deletions
@@ -0,0 +1,176 @@
+const WEBAUDIO_BLOCK_SIZE = 128
+
+/** Overlap-Add Node */
+class OLAProcessor extends window.AudioWorkletProcessor {
+  constructor(options) {
+    super(options)
+
+    this.nbInputs = options.numberOfInputs
+    this.nbOutputs = options.numberOfOutputs
+
+    this.blockSize = options.processorOptions.blockSize
+    // TODO for now, the only support hop size is the size of a web audio block
+    this.hopSize = WEBAUDIO_BLOCK_SIZE
+
+    this.nbOverlaps = this.blockSize / this.hopSize
+
+    // pre-allocate input buffers (will be reallocated if needed)
+    this.inputBuffers = new Array(this.nbInputs)
+    this.inputBuffersHead = new Array(this.nbInputs)
+    this.inputBuffersToSend = new Array(this.nbInputs)
+    // default to 1 channel per input until we know more
+    for (let i = 0; i < this.nbInputs; i++) {
+      this.allocateInputChannels(i, 1)
+    }
+    // pre-allocate input buffers (will be reallocated if needed)
+    this.outputBuffers = new Array(this.nbOutputs)
+    this.outputBuffersToRetrieve = new Array(this.nbOutputs)
+    // default to 1 channel per output until we know more
+    for (let i = 0; i < this.nbOutputs; i++) {
+      this.allocateOutputChannels(i, 1)
+    }
+  }
+
+  /** Handles dynamic reallocation of input/output channels buffer
+     (channel numbers may vary during lifecycle) **/
+  reallocateChannelsIfNeeded(inputs, outputs) {
+    for (let i = 0; i < this.nbInputs; i++) {
+      let nbChannels = inputs[i].length
+      if (nbChannels != this.inputBuffers[i].length) {
+        this.allocateInputChannels(i, nbChannels)
+      }
+    }
+
+    for (let i = 0; i < this.nbOutputs; i++) {
+      let nbChannels = outputs[i].length
+      if (nbChannels != this.outputBuffers[i].length) {
+        this.allocateOutputChannels(i, nbChannels)
+      }
+    }
+  }
+
+  allocateInputChannels(inputIndex, nbChannels) {
+    // allocate input buffers
+
+    this.inputBuffers[inputIndex] = new Array(nbChannels)
+    for (let i = 0; i < nbChannels; i++) {
+      this.inputBuffers[inputIndex][i] = new Float32Array(this.blockSize + WEBAUDIO_BLOCK_SIZE)
+      this.inputBuffers[inputIndex][i].fill(0)
+    }
+
+    // allocate input buffers to send and head pointers to copy from
+    // (cannot directly send a pointer/subarray because input may be modified)
+    this.inputBuffersHead[inputIndex] = new Array(nbChannels)
+    this.inputBuffersToSend[inputIndex] = new Array(nbChannels)
+    for (let i = 0; i < nbChannels; i++) {
+      this.inputBuffersHead[inputIndex][i] = this.inputBuffers[inputIndex][i].subarray(0, this.blockSize)
+      this.inputBuffersToSend[inputIndex][i] = new Float32Array(this.blockSize)
+    }
+  }
+
+  allocateOutputChannels(outputIndex, nbChannels) {
+    // allocate output buffers
+    this.outputBuffers[outputIndex] = new Array(nbChannels)
+    for (let i = 0; i < nbChannels; i++) {
+      this.outputBuffers[outputIndex][i] = new Float32Array(this.blockSize)
+      this.outputBuffers[outputIndex][i].fill(0)
+    }
+
+    // allocate output buffers to retrieve
+    // (cannot send a pointer/subarray because new output has to be add to exising output)
+    this.outputBuffersToRetrieve[outputIndex] = new Array(nbChannels)
+    for (let i = 0; i < nbChannels; i++) {
+      this.outputBuffersToRetrieve[outputIndex][i] = new Float32Array(this.blockSize)
+      this.outputBuffersToRetrieve[outputIndex][i].fill(0)
+    }
+  }
+
+  /** Read next web audio block to input buffers **/
+  readInputs(inputs) {
+    // when playback is paused, we may stop receiving new samples
+    if (inputs[0].length && inputs[0][0].length == 0) {
+      for (let i = 0; i < this.nbInputs; i++) {
+        for (let j = 0; j < this.inputBuffers[i].length; j++) {
+          this.inputBuffers[i][j].fill(0, this.blockSize)
+        }
+      }
+      return
+    }
+
+    for (let i = 0; i < this.nbInputs; i++) {
+      for (let j = 0; j < this.inputBuffers[i].length; j++) {
+        let webAudioBlock = inputs[i][j]
+        this.inputBuffers[i][j].set(webAudioBlock, this.blockSize)
+      }
+    }
+  }
+
+  /** Write next web audio block from output buffers **/
+  writeOutputs(outputs) {
+    for (let i = 0; i < this.nbInputs; i++) {
+      for (let j = 0; j < this.inputBuffers[i].length; j++) {
+        let webAudioBlock = this.outputBuffers[i][j].subarray(0, WEBAUDIO_BLOCK_SIZE)
+        outputs[i][j].set(webAudioBlock)
+      }
+    }
+  }
+
+  /** Shift left content of input buffers to receive new web audio block **/
+  shiftInputBuffers() {
+    for (let i = 0; i < this.nbInputs; i++) {
+      for (let j = 0; j < this.inputBuffers[i].length; j++) {
+        this.inputBuffers[i][j].copyWithin(0, WEBAUDIO_BLOCK_SIZE)
+      }
+    }
+  }
+
+  /** Shift left content of output buffers to receive new web audio block **/
+  shiftOutputBuffers() {
+    for (let i = 0; i < this.nbOutputs; i++) {
+      for (let j = 0; j < this.outputBuffers[i].length; j++) {
+        this.outputBuffers[i][j].copyWithin(0, WEBAUDIO_BLOCK_SIZE)
+        this.outputBuffers[i][j].subarray(this.blockSize - WEBAUDIO_BLOCK_SIZE).fill(0)
+      }
+    }
+  }
+
+  /** Copy contents of input buffers to buffer actually sent to process **/
+  prepareInputBuffersToSend() {
+    for (let i = 0; i < this.nbInputs; i++) {
+      for (let j = 0; j < this.inputBuffers[i].length; j++) {
+        this.inputBuffersToSend[i][j].set(this.inputBuffersHead[i][j])
+      }
+    }
+  }
+
+  /** Add contents of output buffers just processed to output buffers **/
+  handleOutputBuffersToRetrieve() {
+    for (let i = 0; i < this.nbOutputs; i++) {
+      for (let j = 0; j < this.outputBuffers[i].length; j++) {
+        for (let k = 0; k < this.blockSize; k++) {
+          this.outputBuffers[i][j][k] += this.outputBuffersToRetrieve[i][j][k] / this.nbOverlaps
+        }
+      }
+    }
+  }
+
+  process(inputs, outputs, params) {
+    this.reallocateChannelsIfNeeded(inputs, outputs)
+
+    this.readInputs(inputs)
+    this.shiftInputBuffers()
+    this.prepareInputBuffersToSend()
+    this.processOLA(this.inputBuffersToSend, this.outputBuffersToRetrieve, params)
+    this.handleOutputBuffersToRetrieve()
+    this.writeOutputs(outputs)
+    this.shiftOutputBuffers()
+
+    return true
+  }
+
+  processOLA(inputs, outputs, params) {
+    console.assert(false, 'Not overriden')
+  }
+}
+
+export default OLAProcessor