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Revision 1132215 of MediaTrackSettings.sampleSize

  • Revision slug: Web/API/MediaTrackSettings/sampleSize
  • Revision title: MediaTrackSettings.sampleSize
  • Revision id: 1132215
  • Created:
  • Creator: Sheppy
  • Is current revision? Yes
  • Comment New page for bug 1213517

Revision Content

{{APIRef("Media Capture and Streams")}}

The {{domxref("MediaTrackSettings")}} dictionary's sampleSize property is an integer indicating the linear sample size (in bits per sample) the {{domxref("MediaStreamTrack")}} is currently configured for. This lets you determine what value was selected to comply with your specified constraints for this property's value as described in the {{domxref("MediaTrackConstraints.sampleSize")}} property you provided when calling either {{domxref("MediaDevices.getUserMedia", "getUserMedia()")}} or {{domxref("MediaStreamTrack.applyConstraints()")}}.

If needed, you can determine whether or not this constraint is supported by checking the value of {{domxref("MediaTrackSupportedConstraints.sampleSize")}} as returned by a call to {{domxref("MediaDevices.getSupportedConstraints()")}}. However, typically this is unnecessary since browsers will simply ignore any constraints they're unfamiliar with.

Syntax

var sampleSize = MediaTrackSettings.sampleSize;

Value

An integer value indicating how many bits each audio sample is represented by. The most commonly used sample size for many years now is 16 bits per sample, which was used for CD audio among others. Other common sample sizes are 8 (for reduced bandwidth requirements) and 24 (for high-resolution professional audio).

Each audio channel on the track requires sampleSize bits. That means that a given sample actually uses (sampleSize/8)*{{domxref("MediaTrackSettings.channelCount", "channelCount")}} bytes of data. For example, 16-bit stereo audio requires (16/8)*2 or 4 bytes per sample.

Example

See {{SectionOnPage("/en-US/docs/Web/API/Media_Streams_API/Constraints", "Example: Constraint exerciser")}} for an example.

Specifications

Specification Status Comment
{{ SpecName('Media Capture', '#widl-MediaTrackSettings-sampleSize', 'sampleSize') }} {{ Spec2('Media Capture') }} Initial specification.

Browser compatibility

{{CompatibilityTable}}

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
Basic support {{CompatVersionUnknown}} {{CompatNo}} {{CompatNo}} {{CompatVersionUnknown}} {{CompatUnknown}}
Feature Android Android Webview Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile Chrome for Android
Basic support {{CompatUnknown}} {{CompatVersionUnknown}} {{CompatNo}} {{CompatNo}} {{CompatUnknown}} {{CompatUnknown}} {{CompatVersionUnknown}}

See also

Revision Source

<div>{{APIRef("Media Capture and Streams")}}</div>

<p>The {{domxref("MediaTrackSettings")}} dictionary's <code><strong>sampleSize</strong></code> property is an integer indicating the linear sample size (in bits per sample) the {{domxref("MediaStreamTrack")}} is currently configured for. This lets you determine what value was selected to comply with your specified constraints for this property's value as described in the {{domxref("MediaTrackConstraints.sampleSize")}} property you provided when calling either {{domxref("MediaDevices.getUserMedia", "getUserMedia()")}} or {{domxref("MediaStreamTrack.applyConstraints()")}}.</p>

<p>If needed, you can determine whether or not this constraint is supported by checking the value of {{domxref("MediaTrackSupportedConstraints.sampleSize")}} as returned by a call to {{domxref("MediaDevices.getSupportedConstraints()")}}. However, typically this is unnecessary since browsers will simply ignore any constraints they're unfamiliar with.</p>

<h2 id="Syntax">Syntax</h2>

<pre class="syntaxbox">
var <em>sampleSize</em> = <em>MediaTrackSettings</em>.sampleSize;
</pre>

<h3 id="Value">Value</h3>

<p>An integer value indicating how many bits each audio sample is represented by. The most commonly used sample size for many years now is 16 bits per sample, which was used for CD audio among others. Other common sample sizes are 8 (for reduced bandwidth requirements) and 24 (for high-resolution professional audio).</p>

<p>Each audio channel on the track requires sampleSize bits. That means that a given sample actually uses (<code>sampleSize</code>/8)*{{domxref("MediaTrackSettings.channelCount", "channelCount")}} bytes of data. For example, 16-bit stereo audio requires (16/8)*2 or 4 bytes per sample.</p>

<h2 id="Example" name="Example">Example</h2>

<p>See {{SectionOnPage("/en-US/docs/Web/API/Media_Streams_API/Constraints", "Example: Constraint exerciser")}} for an example.</p>

<h2 id="Specifications">Specifications</h2>

<table class="standard-table">
 <thead>
  <tr>
   <th scope="col">Specification</th>
   <th scope="col">Status</th>
   <th scope="col">Comment</th>
  </tr>
 </thead>
 <tbody>
  <tr>
   <td>{{ SpecName('Media Capture', '#widl-MediaTrackSettings-sampleSize', 'sampleSize') }}</td>
   <td>{{ Spec2('Media Capture') }}</td>
   <td>Initial specification.</td>
  </tr>
 </tbody>
</table>

<h2 id="Browser_compatibility">Browser compatibility</h2>

<p>{{CompatibilityTable}}</p>

<div id="compat-desktop">
<table class="compat-table">
 <tbody>
  <tr>
   <th>Feature</th>
   <th>Chrome</th>
   <th>Firefox (Gecko)</th>
   <th>Internet Explorer</th>
   <th>Opera</th>
   <th>Safari</th>
  </tr>
  <tr>
   <td>Basic support</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatNo}}</td>
   <td>{{CompatNo}}</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatUnknown}}</td>
  </tr>
 </tbody>
</table>
</div>

<div id="compat-mobile">
<table class="compat-table">
 <tbody>
  <tr>
   <th>Feature</th>
   <th>Android</th>
   <th>Android Webview</th>
   <th>Firefox Mobile (Gecko)</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>{{CompatNo}}</td>
   <td>{{CompatNo}}</td>
   <td>{{CompatUnknown}}</td>
   <td>{{CompatUnknown}}</td>
   <td>{{CompatVersionUnknown}}</td>
  </tr>
 </tbody>
</table>
</div>

<h2 id="See_also">See also</h2>

<ul>
 <li><a href="/en-US/docs/Web/API/Media_Streams_API">Media Capture and Streams API</a></li>
 <li><a href="/en-US/docs/Web/API/Media_Streams_API/Constraints">Capabilities, constraints, and settings</a></li>
 <li>{{domxref("MediaTrackConstraints.sampleSize")}}</li>
 <li>{{domxref("MediaTrackSettings")}}</li>
</ul>
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