{"id":11026,"date":"2023-10-09T22:50:57","date_gmt":"2023-10-09T14:50:57","guid":{"rendered":"https:\/\/www.zhangxinxu.com\/wordpress\/?p=11026"},"modified":"2023-10-09T22:58:08","modified_gmt":"2023-10-09T14:58:08","slug":"js-web-audio-audiobuffer-volume","status":"publish","type":"post","link":"https:\/\/www.zhangxinxu.com\/wordpress\/2023\/10\/js-web-audio-audiobuffer-volume\/","title":{"rendered":"JS\u6539\u53d8AudioBuffer\u97f3\u91cf\u5e76\u4e0b\u8f7d\u4e3a\u65b0audio\u97f3\u9891"},"content":{"rendered":"<p>by <a href=\"https:\/\/www.zhangxinxu.com\/\">zhangxinxu<\/a> from <a href=\"https:\/\/www.zhangxinxu.com\/wordpress\/?p=11026\">https:\/\/www.zhangxinxu.com\/wordpress\/?p=11026<\/a> \u946b\u7a7a\u95f4-\u946b\u751f\u6d3b<br \/>\n\u672c\u6587\u6b22\u8fce\u5206\u4eab\u4e0e\u805a\u5408\uff0c\u5168\u6587\u8f6c\u8f7d\u5c31\u4e0d\u5fc5\u4e86\uff0c\u5c0a\u91cd\u7248\u6743\uff0c\u5708\u5b50\u5c31\u8fd9\u4e48\u5927\uff0c\u82e5\u6025\u7528\u53ef\u4ee5\u8054\u7cfb\u6388\u6743\u3002<\/p>\n<p><script>window.wxShareImgUrl = 'https:\/\/www.zhangxinxu.com\/study\/image\/share\/202310-audio-volume.png';<\/script><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/image.zhangxinxu.com\/image\/blog\/202310\/audio-wave-cover.png\" width=\"365\" height=\"237\" alt=\"\u97f3\u9891\u6ce2\u5f62\u56fe\" class=\"alignright clip thumb size-medium\" \/><\/p>\n<p>\u5982\u4eca\u7684Web\u8d8a\u6765\u8d8a\u5f3a\uff0c\u51e0\u4e4e\u5e38\u89c1\u7684\u97f3\u89c6\u9891\u5f00\u53d1\u9700\u6c42\u90fd\u80fd\u4f7f\u7528\u7eafJS\u641e\u5b9a\u4e86\u3002<\/p>\n<h3>\u4e00\u3001\u8fd9\u91cc\u9700\u8981\u4e2a\u6807\u9898<\/h3>\n<p>\u8fd9\u91cc\u4ecb\u7ecd\u4e00\u4e2a\u4e0d\u592a\u5e38\u89c1\u7684\u4f7f\u7528\u573a\u666f\u7684\u6280\u672f\u5b9e\u73b0\u3002<\/p>\n<p>\u5565\u5462\uff0c\u5c31\u662f\u97f3\u9891\u7684\u97f3\u91cf\u8c03\u6574\uff0c\u5e76\u8f6c\u6362\u6210\u65b0\u6587\u4ef6\u3002<\/p>\n<p>\u5982\u679c\u4ec5\u4ec5\u662f\u8c03\u6574\u64ad\u653e\u7684\u97f3\u91cf\uff0c\u90a3\u5f88\u7b80\u5355\u3002<\/p>\n<p>\u5982\u679c\u4f60\u4f7f\u7528\u7684\u662f <code>&lt;audio&gt;<\/code> \u5143\u7d20\uff0c\u76f4\u63a5\u6539\u53d8<code>volume<\/code>\u5c5e\u6027\u5c31\u597d\u4e86\u3002<\/p>\n<pre>audio.volume = 0.5;<\/pre>\n<p>over~<\/p>\n<p>\u5982\u679c\u6ca1\u6709audio\u5143\u7d20\uff0c\u800c\u662f\u4f7f\u7528\u7684Web Audio API\uff0c\u5e0c\u671b\u5728 AudioBuffer \u5c42\u9762\u8bbe\u7f6e\u64ad\u653e\u7684\u97f3\u91cf\uff0c\u5219\u53ef\u4ee5\u4f7f\u7528GainNodes\u5b9e\u73b0\u3002<\/p>\n<p>\u5047\u8bbe\u6211\u4eec\u6709\u4e2a\u5728\u7ebf\u7684MP3\u97f3\u9891\u53eb\u505a\u201cbgmusic.mp3\u201d\uff0c\u5219\u53ef\u4ee5\u8fd9\u4e48\u5904\u7406\u3002<\/p>\n<pre>\/\/ \u5b9a\u4e49\u4e00\u4e2aAudioContext\u5bf9\u8c61\r\n\/\/ \u56e0\u4e3a Web Audio API\u90fd\u662f\u6e90\u81ea\u6b64\u5bf9\u8c61\r\nconst audioContext = new AudioContext();\r\n\/\/ \u521b\u5efa\u4e00\u4e2againNode\u5bf9\u8c61\r\n\/\/ gainNode\u53ef\u4ee5\u5bf9\u97f3\u9891\u8f93\u51fa\u8fdb\u884c\u4e00\u4e9b\u63a7\u5236\r\nconst gainNode = audioContext.createGain();\r\n\/\/ \u97f3\u91cf\u8bbe\u7f6e\u4e3a20%\r\ngainNode.gain.value = 0.2;\r\n\/\/ \u8fd9\u4e2a\u5f88\u6709\u5fc5\u8981\uff0c\u5efa\u7acb\u8054\u7cfb\r\ngainNode.connect(audioContext.destination);\r\n\r\n\/\/ \u521b\u5efaAudioBufferSourceNode\r\nlet source = audioContext.createBufferSource();\r\n\/\/ \u83b7\u53d6\u97f3\u9891\u8d44\u6e90\r\nfetch('.\/bgmusic.mp3')\r\n  .then(res =&gt; res.arrayBuffer())\r\n  .then(buffer =&gt; audioContext.decodeAudioData(buffer))\r\n  .then(audioBuffer =&gt; {\r\n    source.buffer = audioBuffer;\r\n    source.connect(gainNode);\r\n  });\r\n\r\n\/\/ \u5f53\u9700\u8981\u64ad\u653e\u7684\u65f6\u5019\uff0c\u6267\u884c\r\nsource.start(0);<\/pre>\n<p>\u60a8\u53ef\u4ee5\u72e0\u72e0\u5730\u70b9\u51fb\u8fd9\u91cc\u4f53\u9a8c\u6548\u679c\uff1a<a href=\"https:\/\/www.zhangxinxu.com\/study\/202310\/js-audio-gainnode-volume-demo.php\" rel=\"noopener\" target=\"_blank\">\u4f7f\u7528gainNode\u6539\u53d8\u97f3\u9891\u64ad\u653e\u97f3\u91cfdemo<\/a><\/p>\n<p>\u4e0a\u9762\u7684\u662f\u539f\u97f3\u9891\uff0c\u97f3\u91cf\u8fd8\u662f\u5f88\u731b\u7684\u3002<\/p>\n<p>\u70b9\u51fb\u4e0b\u9762\u7684\u6309\u94ae\uff0c\u5219\u4f1a\u542c\u5230\u8f7b\u5f88\u591a\u7684\u58f0\u97f3\uff0c\u8fd9\u4e2a\u97f3\u91cf\u7684\u964d\u4f4e\u5c31\u662fGainNodes\u5b9e\u73b0\u7684\u3002<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/image.zhangxinxu.com\/image\/blog\/202310\/2023-10-09_220225.png\" width=\"440\" height=\"297\" alt=\"demo\u9875\u9762\u7684\u70b9\u51fb\u64ad\u653e\u6309\u94ae\" class=\"alignnone size-medium\" \/><\/p>\n<p>\u7136\u800c\uff0cGainNodes\u964d\u4f4e\u97f3\u91cf\u4ec5\u4ec5\u662f\u5728\u64ad\u653e\u5c42\u9762\u7684\u63a7\u5236\uff0c\u5e76\u4e0d\u662f\u6539\u53d8\u539f\u59cb\u7684\u97f3\u9891\u97f3\u91cf\u5927\u5c0f\u3002<\/p>\n<p>\u6240\u4ee5\uff0c\u5982\u679c\u73b0\u5728\u6709\u4e2a\u9700\u6c42\uff0c\u5e0c\u671b\u53ef\u4ee5\u4e0b\u8f7d\u8fd9\u4e2a\u97f3\u91cf\u51cf\u5c0f\u540e\u7684\u97f3\u9891\uff0c\u90a3\u4f7f\u7528gainNode API \u5b9e\u73b0\u7684\u65b9\u6cd5\u5c31\u65e0\u6548\uff0c\u6b64\u65f6\uff0c\u9700\u8981\u501f\u52a9\u5176\u4ed6\u7684\u65b9\u6cd5\u3002<\/p>\n<h3>\u4e8c\u3001\u91c7\u6837\u4e0e\u97f3\u9891\u6570\u636e\u7684\u91cd\u7f6e<\/h3>\n<p>\u97f3\u9891\u7684\u672c\u8d28\u662f\u6ce2\uff0c\u73b0\u5b9e\u4e16\u754c\u7684\u6ce2\u662f\u8fde\u7eed\u7684\uff0c\u4f46\u662f\u97f3\u9891\u5374\u4e0d\u662f\uff0c\u672c\u8d28\u4e0a\u662f\u4e00\u4e2a\u4e00\u4e2a\u7684\u70b9\u91c7\u6837\u6765\u7684\u3002<\/p>\n<p>\u5982\u4e0b\u56fe\u6240\u793a\uff1a<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/image.zhangxinxu.com\/image\/blog\/202310\/2023-10-9_175204.png\" width=\"362\" height=\"257\" alt=\"\u91c7\u6837\u5c31\u662f\u6253\u70b9\" class=\"alignnone size-medium\" \/><\/p>\n<p>\u4f8b\u5982\u57281s\u5185\u625348000\u4e2a\u70b9\uff0c\u90a3\u4e48\u91c7\u6837\u7387\u5c31\u662f48000\u3002<\/p>\n<p>\u91c7\u6837\u7387\u8d8a\u9ad8\uff0c\u97f3\u9891\u8d28\u91cf\u8d8a\u597d\uff0c\u97f3\u9891\u6587\u4ef6\u7684\u4f53\u79ef\u4e5f\u5c31\u8d8a\u5927\u3002<\/p>\n<p>\u6240\u4ee5\uff0c\u60f3\u8981\u6539\u53d8\u97f3\u9891\u539f\u59cb\u7684\u97f3\u91cf\uff0c\u53ef\u4ee5\u83b7\u53d6\u5230\u97f3\u9891\u6bcf\u4e2a\u70b9\u7684\u91c7\u6837\u6570\u636e\uff0c\u7136\u540e\u548c\u97f3\u91cf\u5bf9\u5e94\u7684\u6bd4\u4f8b\u76f8\u4e58\u5c31\u597d\u4e86\u3002<\/p>\n<p>OK\uff0c\u539f\u7406\u6e05\u695a\u4e86\uff0c\u90a3\u8be5\u600e\u4e48\u5b9e\u73b0\u5462\uff1f<\/p>\n<p>\u55ef\u2026\u2026\u60f3\u4e86\u4e0b\uff0c\u8fd8\u662f\u76f4\u63a5\u653e\u4ee3\u7801\u5427\uff0c\u6ca1\u591a\u5c11\u4eba\u5bf9ArrayBuffer\uff0cAudioBuffer\uff0cAudioData\u7b49\u6982\u5ff5\u6709\u5174\u8da3\u7684\u3002<\/p>\n<p>\u5c31\u662f\u8fd9\u4e2a\uff0c\u62ff\u53bb\u590d\u5236\u7c98\u8d34\u5427\u3002<\/p>\n<pre>\/\/ \u97f3\u91cf\r\nconst volume = 0.2;\r\n\/\/ \u5b9a\u4e49\u4e00\u4e2aAudioContext\u5bf9\u8c61\r\n\/\/ \u56e0\u4e3a Web Audio API\u90fd\u662f\u6e90\u81ea\u6b64\u5bf9\u8c61\r\nconst audioContext = new AudioContext();\r\n\/\/ \u964d\u4f4e\u97f3\u91cf\u540e\u7684audioBuffer\u6570\u636e\r\nlet newAudioBuffer = null;\r\n\/\/ \u83b7\u53d6\u97f3\u9891\u8d44\u6e90\r\nfetch('.\/bgmusic.mp3')\r\n  .then(res =&gt; res.arrayBuffer())\r\n  .then(buffer =&gt; audioContext.decodeAudioData(buffer))\r\n  .then(audioBuffer =&gt; {\r\n    newAudioBuffer = new AudioBuffer({\r\n        length: audioBuffer.length,\r\n        numberOfChannels: audioBuffer.numberOfChannels,\r\n        sampleRate: audioBuffer.sampleRate\r\n    });\r\n    \r\n    for (let channel = 0; channel &lt; audioBuffer.numberOfChannels; channel += 1) {\r\n        const channelData = audioBuffer.getChannelData(channel);\r\n        const copiedChannelData = newAudioBuffer.getChannelData(channel);\r\n    \r\n        for (let sample = 0; sample &lt; channelData.length; sample += 1) {\r\n            copiedChannelData[sample] = channelData[sample] * volume;\r\n        }\r\n    }\r\n});<\/pre>\n<p>\u6b64\u65f6\uff0c<code>newAudioBuffer<\/code>\u5c31\u662f\u97f3\u91cf\u964d\u4f4e\u523020%\u65f6\u5019\u7684audioBuffer\u6570\u636e\u3002<\/p>\n<p>\u6211\u4eec\u53ef\u4ee5\u4f7f\u7528\u6b64\u6570\u636e\u8fdb\u884c\u97f3\u9891\u7684\u64ad\u653e\uff0c\u6216\u8005\u7f16\u7801\uff0c\u6216\u8005\u4e0b\u8f7d\uff0c\u90fd\u53ef\u4ee5\u3002<\/p>\n<h3>\u4e09\u3001\u5982\u4f55\u4f5c\u4e3a\u6587\u4ef6\u4e0b\u8f7d<\/h3>\n<p>\u8fd9\u4e2a<a href=\"https:\/\/www.zhangxinxu.com\/wordpress\/2020\/07\/js-audio-clip-copy-upload\/\">\u4ee5\u524d\u5176\u5b9e\u5206\u4eab\u8fc7<\/a>\uff0c\u7eafJS\u5408\u6210\u97f3\u9891\uff0c\u6216\u8005\u8bf4AudioBuffer\u6570\u636e\u8f6c\u97f3\u9891\uff0c\u76ee\u524d\u53ea\u652f\u6301wav\u683c\u5f0f\uff08\u54ea\u6015\u540e\u7f00\u662fmp3\uff0c\u5176\u5b9e\u4e5f\u662fwav\u683c\u5f0f\uff09\u3002<\/p>\n<pre>\/\/ \u8f6c\u6362 AudioBuffer \u4e3a Wave \u683c\u5f0f\u7684 Blob \u5730\u5740\r\nfunction bufferToWave(abuffer, len) {\r\n    \/\/ \u7565\uff0c\u8be6\u89c1\u4e0b\u9762\u7684\u6f14\u793a\u9875\u9762\r\n}<\/pre>\n<p>\u60a8\u53ef\u4ee5\u72e0\u72e0\u5730\u70b9\u51fb\u8fd9\u91cc\uff1a<a href=\"https:\/\/www.zhangxinxu.com\/study\/202310\/js-audio-gechanneldata-sample-volume-demo.php\" rel=\"noopener\" target=\"_blank\">MP3\u97f3\u9891\u5728\u7ebf\u97f3\u91cf\u964d\u4f4e\u5e76\u4e0b\u8f7ddemo<\/a><\/p>\n<p>\u70b9\u51fb\u6309\u94ae\u540e\uff0c\u6267\u884c\u7c7b\u4f3c\u4e0b\u9762\u7684JS\u4ee3\u7801\uff1a<\/p>\n<pre>const blob = bufferToWave(newAudioBuffer, newAudioBuffer.length);<\/pre>\n<p>\u5c31\u53ef\u4ee5get\u5230\u97f3\u91cf\u964d\u4f4e\u540e\u7684\u97f3\u9891\u4e86\uff0c\u4f60\u4e5f\u53ef\u4ee5\u9009\u62e9\u4e0b\u8f7d\u6b64\u97f3\u9891\u3002<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/image.zhangxinxu.com\/image\/blog\/202310\/2023-10-09_223407.png\" width=\"536\" height=\"368\" alt=\"\u70b9\u51fb\u6309\u94ae\u540e\u7684\u6548\u679c\u9884\u89c8\" class=\"alignnone size-medium\" \/><\/p>\n<h3>\u56db\u3001\u672c\u6587\u53ea\u662f\u5f00\u80c3\u83dc<\/h3>\n<p>\u672c\u6587\u53ea\u662f\u5f00\u80c3\u83dc\uff0c\u4e0b\u4e00\u7bc7\u6587\u7ae0\uff0c\u6211\u4eec\u4f1a\u66f4\u8fdb\u4e00\u6b65\uff0c\u770b\u770b\u5982\u4f55\u501f\u52a9 Web Audio API \u5b9e\u73b0\u97f3\u9891\u7684\u62fc\u63a5\u4e0e\u5408\u5e76\u3002<\/p>\n<p>\u5662\u5566\uff0c\u5c06\u634f\u3002<\/p>\n<p>\u201c\u5c06\u634f\u201d\u662f\u518d\u89c1\u7684\u610f\u601d\u3002<\/p>\n<p>\u8868\u793a\u672c\u6587\u6b63\u6587\u5185\u5bb9\u5230\u6b64\u4e3a\u6b62\u4e86\u3002<\/p>\n<p>\u8981\u662f\u672c\u6587\u7684\u5185\u5bb9\u5bf9\u4f60\u7684\u5de5\u4f5c\u6216\u5b66\u4e60\u5e2e\u4e86\u5927\u5fd9\uff0c\u60f3\u8981\u804a\u8868\u8c22\u610f\uff0c\u53ef\u4ee5\u7b49\u4ec0\u4e48\u65f6\u5019\u4eac\u4e1c\u641e\u6d3b\u52a8\u7684\u65f6\u5019\uff0c\u5165\u624b\u6211\u7684\u300aCSS\u4e16\u754c\u300b\u4e09\u90e8\u66f2\u2026\u2026\u4e4b\u4e00\u5c31\u53ef\u4ee5\u4e86\u3002<\/p>\n<p>\u5f53\u7136\uff0c\u4e5f\u6b22\u8fce\u70b9\u8d5e\u6216<button onclick=\"shareWeixin.click()\" class=\"entry-share-btn\">\u5206\u4eab<\/button>\u3002<\/p>\n<p> ? ? ? ? ?<\/p>\n<p>\u672c\u6587\u4e3a\u539f\u521b\u6587\u7ae0\uff0c\u6b22\u8fce\u5206\u4eab\uff0c\u52ff\u5168\u6587\u8f6c\u8f7d\uff0c\u5982\u679c\u5b9e\u5728\u559c\u6b22\uff0c\u53ef\u6536\u85cf\uff0c\u6c38\u4e0d\u8fc7\u671f\uff0c\u4e14\u4f1a\u53ca\u65f6\u66f4\u65b0\u77e5\u8bc6\u70b9\u53ca\u4fee\u6b63\u9519\u8bef\uff0c\u9605\u8bfb\u4f53\u9a8c\u4e5f\u66f4\u597d\u3002<br \/>\n\u672c\u6587\u5730\u5740\uff1a<a href=\"https:\/\/www.zhangxinxu.com\/wordpress\/?p=11026\">https:\/\/www.zhangxinxu.com\/wordpress\/?p=11026<\/a><\/p>\n<p>\uff08\u672c\u7bc7\u5b8c\uff09<\/p>\n","protected":false},"excerpt":{"rendered":"<p><img decoding=\"async\" src=\"https:\/\/image.zhangxinxu.com\/image\/blog\/202310\/audio-wave-cover.png\" width=\"160\" height=\"104\" alt=\"\u97f3\u9891\u6ce2\u5f62\u56fe\" class=\"alignright size-medium\" loading=\"lazy\" \/><\/p>\n<p>\u672c\u6587\u4ecb\u7ecd\u4e09\u79cd\u6539\u53d8\u97f3\u9891\u64ad\u653e\u97f3\u91cf\u7684\u65b9\u6cd5\uff0c\u5176\u4e2d\u8fd8\u6709\u4e00\u79cd\u65b9\u6cd5\u76f4\u63a5\u6539\u53d8\u97f3\u9891AudioBuffer\u6570\u636e\u6e90\u7684\u97f3\u91cf\uff0c\u8bf4\u4e0d\u5b9a\u4f60\u54ea\u5929\u5c31\u4f1a\u7528\u5230\u3002<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[180],"tags":[874,489,1638,1137,1921,1918,1945,1824,1422],"_links":{"self":[{"href":"https:\/\/www.zhangxinxu.com\/wordpress\/wp-json\/wp\/v2\/posts\/11026"}],"collection":[{"href":"https:\/\/www.zhangxinxu.com\/wordpress\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.zhangxinxu.com\/wordpress\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.zhangxinxu.com\/wordpress\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.zhangxinxu.com\/wordpress\/wp-json\/wp\/v2\/comments?post=11026"}],"version-history":[{"count":0,"href":"https:\/\/www.zhangxinxu.com\/wordpress\/wp-json\/wp\/v2\/posts\/11026\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.zhangxinxu.com\/wordpress\/wp-json\/wp\/v2\/media?parent=11026"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.zhangxinxu.com\/wordpress\/wp-json\/wp\/v2\/categories?post=11026"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.zhangxinxu.com\/wordpress\/wp-json\/wp\/v2\/tags?post=11026"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}