TeaWeb/js/codec/BasicCodec.ts

91 lines
3.4 KiB
TypeScript

/// <reference path="Codec.ts"/>
class AVGCalculator {
history_size: number = 100;
history: number[] = [];
push(entry: number) {
while(this.history.length > this.history_size)
this.history.pop();
this.history.unshift(entry);
}
avg() : number {
let count = 0;
for(let entry of this.history)
count += entry;
return count / this.history.length;
}
}
abstract class BasicCodec implements Codec {
protected _audioContext: OfflineAudioContext;
protected _decodeResampler: AudioResampler;
protected _encodeResampler: AudioResampler;
protected _codecSampleRate: number;
protected _latenz: AVGCalculator = new AVGCalculator();
on_encoded_data: (Uint8Array) => void = $ => {};
channelCount: number = 1;
samplesPerUnit: number = 960;
constructor(codecSampleRate: number) {
this.channelCount = 1;
this.samplesPerUnit = 960;
this._audioContext = new OfflineAudioContext(AudioController.globalContext.destination.channelCount, 1024,AudioController.globalContext.sampleRate );
this._codecSampleRate = codecSampleRate;
this._decodeResampler = new AudioResampler(AudioController.globalContext.sampleRate);
this._encodeResampler = new AudioResampler(codecSampleRate);
}
abstract name() : string;
abstract initialise() : Promise<Boolean>;
abstract initialized() : boolean;
abstract deinitialise();
abstract reset() : boolean;
protected abstract decode(data: Uint8Array) : Promise<AudioBuffer>;
protected abstract encode(data: AudioBuffer) : Promise<Uint8Array | string>;
encodeSamples(cache: CodecClientCache, pcm: AudioBuffer) {
this._encodeResampler.resample(pcm).then(buffer => this.encodeSamples0(cache, buffer))
.catch(error => console.error("Could not resample PCM data for codec. Error:" + error));
}
private encodeSamples0(cache: CodecClientCache, buffer: AudioBuffer) {
cache._chunks.push(new BufferChunk(buffer)); //TODO multi channel!
while(cache.bufferedSamples(this.samplesPerUnit) >= this.samplesPerUnit) {
let buffer = this._audioContext.createBuffer(this.channelCount, this.samplesPerUnit, this._codecSampleRate);
let index = 0;
while(index < this.samplesPerUnit) {
let buf = cache._chunks[0];
let cpyBytes = buf.copyRangeTo(buffer, this.samplesPerUnit - index, index);
index += cpyBytes;
buf.index += cpyBytes;
if(buf.index == buf.buffer.length)
cache._chunks.pop_front();
}
let encodeBegin = Date.now();
this.encode(buffer).then(result => {
if(result instanceof Uint8Array) {
let time = Date.now() - encodeBegin;
if(time > 20)
console.error("Required time: %d", time);
//if(time > 20)
// chat.serverChat().appendMessage("Required decode time: " + time);
this.on_encoded_data(result);
}
else console.error("[Codec][" + this.name() + "] Could not encode buffer. Result: " + result);
});
}
return true;
}
decodeSamples(cache: CodecClientCache, data: Uint8Array) : Promise<AudioBuffer> {
return this.decode(data).then(buffer => this._decodeResampler.resample(buffer));
}
}