音频流转mp3格式

  1. function convertToMp3(wavDataView) {
  2.   // 获取wav头信息
  3.   const wav = lamejs.WavHeader.readHeader(wavDataView);
  4.   const { channels, sampleRate } = wav;
  5.   const mp3enc = new lamejs.Mp3Encoder(channels, sampleRate, 128);
  6.   // 获取左右通道数据
  7.   const result = recorder.getChannelData();
  8.   const buffer = [];
  10.   const leftData = result.left && new Int16Array(result.left.buffer, 0, result.left.byteLength / 2);
  11.   const rightData = result.right && new Int16Array(result.right.buffer, 0, result.right.byteLength / 2);
  12.   const remaining = leftData.length + (rightData ? rightData.length : 0);
  14.   const maxSamples = 1152;
  15.   for (let i = 0; i < remaining; i += maxSamples) {
  16.     const left = leftData.subarray(i, i + maxSamples);
  17.     let right = null;
  18.     let mp3buf = null;
  20.     if (channels === 2) {
  21.       right = rightData.subarray(i, i + maxSamples);
  22.       mp3buf = mp3enc.encodeBuffer(left, right);
  23.     } else {
  24.       mp3buf = mp3enc.encodeBuffer(left);
  25.     }
  27.     if (mp3buf.length > 0) {
  28.       buffer.push(mp3buf);
  29.     }
  30.   }
  32.   const enc = mp3enc.flush();
  34.   if (enc.length > 0) {
  35.     buffer.push(enc);
  36.   }
  38.   let blob = new Blob(buffer, {
  39.     type: "audio/mp3",
  40.   });
  41.   return blob;
  42. }

获取 Gop 大小(关键帧间隔)

  1. <script src="https://j.weizan.cn/zhibo/js/jquery-2.1.4.min.js"></script>
  3. $.ajax({
  4.   url: video_src, // 视频播放地址
  5.   dataType: "TEXT",
  6.   success: (res) => {
  7.     // 解析 m3u8 
  8.     var m3u8list = res.replace(/\n/g, '<br>').split('<br>');
  9.     // 获取 Gop 大小
  10.     var gopSize = parseInt(m3u8list[3].split(':').pop());
  11.     console.log('gop size:' + gopSize);
  12.   }
  13. })