No sound in trimmed & encoded audio blob, Vue 2. Why?

[Dmitriy Uvin]

I am trying to cut my mp3 audio in browser and then encode in to blob back and play using blob url, but i receive audio with needed length but without any sound, why so? Need help!

<input type="file" @change="onUploadFile" accept="audio/mpeg, .mp3">

async onUploadFile(event) { const fileData = event.target.files[0]; this.file = fileData; const arrayBuffer = await this.readAudio(fileData); await this.decodeFile(arrayBuffer); }

async readAudio(file) { return new Promise((resolve, reject) => { const reader = new FileReader(); reader.readAsArrayBuffer(file); reader.onload = function () { resolve(reader.result); } }); },

`
async decodeFile(arrayBuffer) {
const audioContext = new AudioContext()
const audioBuffer = await audioContext.decodeAudioData(arrayBuffer);
const begin = 5;
const end = 15;

        await this.audioBufferSlice(audioBuffer, begin, end);
    },

`

async audioBufferSlice(audioBuffer, begin, end) {
const audioContext = new AudioContext();
const channels = audioBuffer.numberOfChannels;
const rate = audioBuffer.sampleRate;
const duration = audioBuffer.duration;
const startOffset = rate * begin;
const endOffset = rate * end;

        const audioLength = endOffset - startOffset;

        let trimmedAudio = audioContext.createBuffer(
            audioBuffer.numberOfChannels,
            audioLength,
            audioBuffer.sampleRate
        );

        for(var i = 0; i < audioBuffer.numberOfChannels; i++){
            trimmedAudio.copyToChannel(audioBuffer.getChannelData(i).slice(begin, end), i);
        }

        let audioData = {
            channels: Array.apply(null,{length: trimmedAudio.numberOfChannels})
                .map(function(currentElement, index) {
                    return trimmedAudio.getChannelData(index);
                }),
            sampleRate: trimmedAudio.sampleRate,
            length: trimmedAudio.length,
        }

        let mp3Data = [];
        const sampleBlockSize = 1152;

        let mp3encoder = new lamejs.Mp3Encoder(2, audioData.sampleRate, 128);

        var left = new Int8Array(audioData.channels[0].length);
        var right = new Int8Array(audioData.channels[1].length);

        for (var i = 0; i < audioData.channels[0].length; i += sampleBlockSize) {
            var leftChunk = left.subarray(i, i + sampleBlockSize);
            var rightChunk = right.subarray(i, i + sampleBlockSize);
            var mp3buf = await mp3encoder.encodeBuffer(leftChunk, rightChunk);
            if (mp3buf.length > 0) {
                mp3Data.push(mp3buf);
            }
        }

        let buf = await mp3encoder.flush();

        if (buf.length > 0) {
            mp3Data.push(buf);
        }

        var blob = new Blob(mp3Data, {type: 'audio/mp3'});
        var url = window.URL.createObjectURL(blob);
        console.log('MP3 URl: ', url);
    },

`
@zhuker