dev@129: /**
dev@129:  * Created by lucast on 16/03/2017.
dev@129:  */
dev@129: import {RealFft, KissRealFft} from "piper/fft/RealFft";
dev@129: import {hann} from "piper/FftUtilities";
dev@129: import {Framing} from "piper";
dev@129: import Waves from 'waves-ui';
dev@129: 
dev@129: class SpectrogramEntity extends Waves.utils.MatrixEntity {
dev@129: 
dev@129:   private samples: Float32Array;
dev@129:   private framing: Framing;
dev@129:   private fft: RealFft;
dev@129:   private real: Float32Array;
dev@129:   private nCols: number;
cannam@130:   private columnHeight: number;
dev@129:   private window: Float32Array;
dev@129: 
dev@129:   constructor(samples: Float32Array, options: Framing & Object) {
dev@129:     super();
dev@129:     this.samples = samples;
dev@129:     this.framing = options;
dev@129:     this.real = new Float32Array(this.framing.blockSize);
dev@129:     this.nCols = Math.floor(this.samples.length / this.framing.stepSize); //!!! not correct
cannam@130:     this.columnHeight = Math.round(this.framing.blockSize / 2) + 1;
dev@129:     this.fft = new KissRealFft(this.framing.blockSize);
dev@129:     this.window = hann(this.framing.blockSize);
dev@129:   }
dev@129: 
cannam@131:   dispose(): void {
cannam@131:     this.fft.dispose();
cannam@131:   }
cannam@131: 
dev@129:   getColumnCount(): number {
dev@129:     return this.nCols;
dev@129:   }
dev@129: 
dev@129:   getColumnHeight(): number {
cannam@130:     return this.columnHeight;
dev@129:   }
dev@129: 
dev@129:   getColumn(n: number): Float32Array {
dev@129: 
dev@129:     const startSample = n * this.framing.stepSize;
dev@129:     const sz = this.framing.blockSize;
dev@129: 
dev@129:     this.real.fill(0);
dev@129: 
dev@129:     let available = sz;
dev@129:     if (startSample + sz >= this.samples.length) {
dev@129:       available = this.samples.length - startSample;
dev@129:     }
dev@129: 
dev@129:     for (let i = 0; i < available; ++i) {
dev@129:       this.real[i] = this.samples[startSample + i] * this.window[i];
dev@129:     }
dev@129: 
dev@129:     const complex = this.fft.forward(this.real);
dev@129: 
dev@129:     const h = this.getColumnHeight();
dev@129:     const col = new Float32Array(h);
dev@129: 
cannam@130:     const scale = 1.0 / Math.sqrt(sz);
dev@129:     for (let i = 0; i < h; ++i) {
cannam@130:       const re : number = complex[i*2] * scale;
cannam@130:       const im : number = complex[i*2+1] * scale;
cannam@130:       const mag = Math.sqrt(re * re + im * im);
cannam@130:       col[i] = mag;
dev@129:     }
dev@129: 
dev@129:     return col;
dev@129:   }
dev@129: }
dev@129: 
dev@129: export class WavesSpectrogramLayer extends Waves.core.Layer {
dev@129:   constructor(buffer: AudioBuffer,
dev@129:               options: Framing & Object) {
dev@129: 
dev@129:     const defaults = {
dev@129:       normalise: 'hybrid',
dev@129:       gain: 40.0,
dev@129:       channel: 0,
dev@129:       stepSize: 512,
dev@129:       blockSize: 1024
dev@129:     };
dev@129: 
dev@129:     const mergedOptions: Framing & Object & {channel: number} =
dev@129:       Object.assign({}, defaults, options);
dev@129: 
dev@129:     super('entity',
dev@129:       new SpectrogramEntity(
dev@129:         buffer.getChannelData(mergedOptions.channel),
dev@129:         mergedOptions
dev@129:       ),
dev@129:       mergedOptions
dev@129:     );
dev@129: 
dev@129:     this.configureShape(Waves.shapes.Matrix, {}, mergedOptions);
dev@129:   }
dev@129: }