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author | Florian Merz <me@fiji-flo.de> | 2021-02-11 12:56:40 +0100 |
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committer | Florian Merz <me@fiji-flo.de> | 2021-02-11 12:56:40 +0100 |
commit | 310fd066e91f454b990372ffa30e803cc8120975 (patch) | |
tree | d5d900deb656a5da18e0b60d00f0db73f3a2e88e /files/zh-cn/web/api/baseaudiocontext/createscriptprocessor | |
parent | 8260a606c143e6b55a467edf017a56bdcd6cba7e (diff) | |
download | translated-content-310fd066e91f454b990372ffa30e803cc8120975.tar.gz translated-content-310fd066e91f454b990372ffa30e803cc8120975.tar.bz2 translated-content-310fd066e91f454b990372ffa30e803cc8120975.zip |
unslug zh-cn: move
Diffstat (limited to 'files/zh-cn/web/api/baseaudiocontext/createscriptprocessor')
-rw-r--r-- | files/zh-cn/web/api/baseaudiocontext/createscriptprocessor/index.html | 199 |
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diff --git a/files/zh-cn/web/api/baseaudiocontext/createscriptprocessor/index.html b/files/zh-cn/web/api/baseaudiocontext/createscriptprocessor/index.html new file mode 100644 index 0000000000..7e505bc06a --- /dev/null +++ b/files/zh-cn/web/api/baseaudiocontext/createscriptprocessor/index.html @@ -0,0 +1,199 @@ +--- +title: AudioContext.createScriptProcessor() +slug: Web/API/AudioContext/createScriptProcessor +translation_of: Web/API/BaseAudioContext/createScriptProcessor +--- +<p>{{ APIRef("Web Audio API") }}</p> + +<div> +<p>{{ domxref("AudioContext") }} 接口的<code>createScriptProcessor()</code> 方法创建一个{{domxref("ScriptProcessorNode")}} 用于通过JavaScript直接处理音频.</p> +</div> + +<h2 id="语法">语法</h2> + +<pre class="brush: js">var audioCtx = new AudioContext(); +myScriptProcessor = audioCtx.createScriptProcessor(<code>bufferSize</code>, <code>numberOfInputChannels</code>, <code>numberOfOutputChannels</code>);</pre> + +<h3 id="Parameters" name="Parameters">参数</h3> + +<dl> + <dt><code>bufferSize</code></dt> + <dd>缓冲区大小,以样本帧为单位。具体来讲,缓冲区大小必须是下面这些值当中的某一个: 256, 512, 1024, 2048, 4096, 8192, 16384. 如果不传,或者参数为0,则取当前环境最合适的缓冲区大小, 取值为2的幂次方的一个常数,在该node的整个生命周期中都不变.</dd> + <dd>该取值控制着<code>audioprocess事件被分派的频率,以及每一次调用多少样本帧被处理</code>. 较低bufferSzie将导致一定的延迟。较高的bufferSzie就要注意避免音频的崩溃和故障。推荐作者不要给定具体的缓冲区大小,让系统自己选一个好的值来平衡延迟和音频质量。</dd> + <dt><code>numberOfInputChannels</code></dt> + <dd>值为整数,用于指定输入node的声道的数量,默认值是2,最高能取32.</dd> + <dt><code>numberOfOutputChannels</code></dt> + <dd>值为整数,用于指定输出node的声道的数量,默认值是2,最高能取32.</dd> +</dl> + +<div class="warning"> +<p><span style="font-size: 14px;"><strong>重要</strong></span>: Webkit (version 31)要求调用这个方法的时候必须传入一个有效的bufferSize .</p> +</div> + +<div class="note"> +<p><span style="font-size: 14px;"><strong>注意</strong></span>: <code>numberOfInputChannels<font face="Open Sans, Arial, sans-serif">和</font></code><code>numberOfOutputChannels的值不能同时为0,二者同时为0是无效的</code></p> +</div> + +<h3 id="Description" name="Description">返回</h3> + +<p>A {{domxref("ScriptProcessorNode")}}.</p> + +<h2 id="示例">示例</h2> + +<p><code><font face="Open Sans, Arial, sans-serif">下面的例子展示了一个</font>ScriptProcessorNode的基本用法,数据源取自</code> {{ domxref("AudioContext.decodeAudioData") }}, 给每一个音频样本加一点白噪声,然后通过{{domxref("AudioDestinationNode")}}播放(其实这个就是系统的扬声器)。 对于每一个声道和样本帧,在把结果当成输出样本之前,<code>scriptNode.onaudioprocess方法<font face="Open Sans, Arial, sans-serif">关联</font></code><code>audioProcessingEvent</code> ,并用它来遍历每输入流的每一个声道,和每一个声道中的每一个样本,并添加一点白噪声。</p> + +<div class="note"> +<p><span style="font-size: 14px;"><strong>注意</strong></span>: 完整的示例参照 <a href="https://mdn.github.io/webaudio-examples/script-processor-node/">script-processor-node</a> github (查看源码 <a href="https://github.com/mdn/webaudio-examples/blob/master/script-processor-node/index.html">source code</a>.)</p> +</div> + +<pre class="brush: js">var myScript = document.querySelector('script'); +var myPre = document.querySelector('pre'); +var playButton = document.querySelector('button'); + +// Create AudioContext and buffer source +var audioCtx = new AudioContext(); +source = audioCtx.createBufferSource(); + +// Create a ScriptProcessorNode with a bufferSize of 4096 and a single input and output channel +var scriptNode = audioCtx.createScriptProcessor(4096, 1, 1); +console.log(scriptNode.bufferSize); + +// load in an audio track via XHR and decodeAudioData + +function getData() { + request = new XMLHttpRequest(); + request.open('GET', 'viper.ogg', true); + request.responseType = 'arraybuffer'; + request.onload = function() { + var audioData = request.response; + + audioCtx.decodeAudioData(audioData, function(buffer) { + myBuffer = buffer; + source.buffer = myBuffer; + }, + function(e){"Error with decoding audio data" + e.err}); + } + request.send(); +} + +// Give the node a function to process audio events +scriptNode.onaudioprocess = function(audioProcessingEvent) { + // The input buffer is the song we loaded earlier + var inputBuffer = audioProcessingEvent.inputBuffer; + + // The output buffer contains the samples that will be modified and played + var outputBuffer = audioProcessingEvent.outputBuffer; + + // Loop through the output channels (in this case there is only one) + for (var channel = 0; channel < outputBuffer.numberOfChannels; channel++) { + var inputData = inputBuffer.getChannelData(channel); + var outputData = outputBuffer.getChannelData(channel); + + // Loop through the 4096 samples + for (var sample = 0; sample < inputBuffer.length; sample++) { + // make output equal to the same as the input + outputData[sample] = inputData[sample]; + + // add noise to each output sample + outputData[sample] += ((Math.random() * 2) - 1) * 0.2; + } + } +} + +getData(); + +// wire up play button +playButton.onclick = function() { + source.connect(scriptNode); + scriptNode.connect(audioCtx.destination); + source.start(); +} + +// When the buffer source stops playing, disconnect everything +source.onended = function() { + source.disconnect(scriptNode); + scriptNode.disconnect(audioCtx.destination); +} +</pre> + +<h2 id="规范">规范</h2> + +<table class="standard-table"> + <tbody> + <tr> + <th scope="col">Specification</th> + <th scope="col">Status</th> + <th scope="col">Comment</th> + </tr> + <tr> + <td>{{SpecName('Web Audio API', '#widl-AudioContext-createScriptProcessor-ScriptProcessorNode-unsigned-long-bufferSize-unsigned-long-numberOfInputChannels-unsigned-long-numberOfOutputChannels', 'createScriptProcessor')}}</td> + <td>{{Spec2('Web Audio API')}}</td> + <td></td> + </tr> + </tbody> +</table> + +<h2 id="浏览器兼容性">浏览器兼容性</h2> + +<div>{{CompatibilityTable}}</div> + +<div id="compat-desktop"> +<table class="compat-table"> + <tbody> + <tr> + <th>Feature</th> + <th>Chrome</th> + <th>Edge</th> + <th>Firefox (Gecko)</th> + <th>Internet Explorer</th> + <th>Opera</th> + <th>Safari (WebKit)</th> + </tr> + <tr> + <td>Basic support</td> + <td>{{CompatChrome(10.0)}}{{property_prefix("webkit")}}</td> + <td>{{CompatVersionUnknown}}</td> + <td>{{CompatGeckoDesktop(25.0)}} </td> + <td>{{CompatNo}}</td> + <td>15.0{{property_prefix("webkit")}}<br> + 22 (unprefixed)</td> + <td>6.0{{property_prefix("webkit")}}</td> + </tr> + </tbody> +</table> +</div> + +<div id="compat-mobile"> +<table class="compat-table"> + <tbody> + <tr> + <th>Feature</th> + <th>Android</th> + <th>Edge</th> + <th>Firefox Mobile (Gecko)</th> + <th>Firefox OS</th> + <th>IE Mobile</th> + <th>Opera Mobile</th> + <th>Safari Mobile</th> + <th>Chrome for Android</th> + </tr> + <tr> + <td>Basic support</td> + <td>{{CompatUnknown}}</td> + <td>{{CompatVersionUnknown}}</td> + <td>26.0</td> + <td>1.2</td> + <td>{{CompatUnknown}}</td> + <td>{{CompatUnknown}}</td> + <td>{{CompatUnknown}}</td> + <td>33.0</td> + </tr> + </tbody> +</table> +</div> + +<h2 id="See_also">See also</h2> + +<ul> + <li><a href="/en-US/docs/Web_Audio_API/Using_Web_Audio_API">Using the Web Audio API</a></li> +</ul> |