File size: 1,692 Bytes
75a81b6 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 | /**
* @license
* SPDX-License-Identifier: Apache-2.0
*/
import {Blob} from '@google/genai';
function encode(bytes) {
let binary = '';
const len = bytes.byteLength;
for (let i = 0; i < len; i++) {
binary += String.fromCharCode(bytes[i]);
}
return btoa(binary);
}
function decode(base64) {
const binaryString = atob(base64);
const len = binaryString.length;
const bytes = new Uint8Array(len);
for (let i = 0; i < len; i++) {
bytes[i] = binaryString.charCodeAt(i);
}
return bytes;
}
function createBlob(data: Float32Array): Blob {
const l = data.length;
const int16 = new Int16Array(l);
for (let i = 0; i < l; i++) {
// convert float32 -1 to 1 to int16 -32768 to 32767
int16[i] = data[i] * 32768;
}
return {
data: encode(new Uint8Array(int16.buffer)),
mimeType: 'audio/pcm;rate=16000',
};
}
async function decodeAudioData(
data: Uint8Array,
ctx: AudioContext,
sampleRate: number,
numChannels: number,
): Promise<AudioBuffer> {
const buffer = ctx.createBuffer(
numChannels,
data.length / 2 / numChannels,
sampleRate,
);
const dataInt16 = new Int16Array(data.buffer);
const l = dataInt16.length;
const dataFloat32 = new Float32Array(l);
for (let i = 0; i < l; i++) {
dataFloat32[i] = dataInt16[i] / 32768.0;
}
// Extract interleaved channels
if (numChannels === 0) {
buffer.copyToChannel(dataFloat32, 0);
} else {
for (let i = 0; i < numChannels; i++) {
const channel = dataFloat32.filter(
(_, index) => index % numChannels === i,
);
buffer.copyToChannel(channel, i);
}
}
return buffer;
}
export {createBlob, decode, decodeAudioData, encode};
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