page.title=OEM Dependencies for Media Resource Manager
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  <div id="qv">
    <h2>In this document</h2>
    <ol id="auto-toc">
    </ol>
  </div>
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<p>This document is intended to help original equipment manufacturers (OEMs)
properly implement support for Android media resource manager and related APIs.</p>

<h2 id=1_max_concurrent_codec_instances>1. Max concurrent codec instances</h2>

<p>The <code>CodecCapabilities.getMaxSupportedInstances</code> interface
returns the maximum number of supported concurrent codec instances.</p>

<p>The CTS test 
<code>testGetMaxSupportedInstances(android.media.cts.MediaCodecCapabilitiesTest)</code>
is used to enforce the proper maximum is set in 
<code>/etc/media_codecs.xml</code>.</p>

<p>Here is an example:</p>

<pre>
...
&lt;MediaCodecs&gt;
    ...
    &lt;Encoders&gt;
        &lt;MediaCodec name="OMX.<em>&lt;vendor&gt;</em>.video.encoder.avc" type="video/avc" &gt;
           ...
            &lt;Limit name="concurrent-instances" max="13" /&gt;
        &lt;/MediaCodec&gt;
        ...
    &lt;/Encoders&gt;
    ...
&lt;/MediaCodecs&gt;
</pre>

<p>OEMs can use this test to generate the concurrent limits that pass the test.
To do this:</p>

  <ol>
    <li>Run the test first using cts-tradefed.
    <li>Evaluate the resulting failure message. Here is an example:

<pre>
There was 1 failure:
1) testGetMaxSupportedInstances(android.media.cts.MediaCodecCapabilitiesTest)
junit.framework.AssertionFailedError: In order to pass the test, please publish
following codecs' concurrent instances limit in /etc/media_codecs.xml:
&lt;MediaCodec name="OMX.<em>&lt;vendor&gt;</em>.video.encoder.mpeg4" type="video/mp4v-es" &gt;
    &lt;Limit name="concurrent-instances" max="13" /&gt;
&lt;/MediaCodec&gt;
&lt;MediaCodec name="OMX.<em>&lt;vendor&gt;</em>.video.encoder.h263" type="video/3gpp" &gt;
    &lt;Limit name="concurrent-instances" max="13" /&gt;
&lt;/MediaCodec&gt;
&lt;MediaCodec name="OMX.<em>&lt;vendor&gt;</em>.video.encoder.avc" type="video/avc" &gt;
    &lt;Limit name="concurrent-instances" max="13" /&gt;
&lt;/MediaCodec>
&lt;MediaCodec name="OMX.<em>&lt;vendor&gt;</em>.video.encoder.vp8" type="video/x-vnd.on2.vp8" &gt;
    &lt;Limit name="concurrent-instances" max="13" /&gt;
&lt;/MediaCodec&gt;
&lt;MediaCodec name="OMX.<em>&lt;vendor&gt;</em>.video.decoder.avc" type="video/avc" &gt;
    &lt;Limit name="concurrent-instances" max="13" /&gt;
&lt;/MediaCodec&gt;
&lt;MediaCodec name="OMX.<em>&lt;vendor&gt;</em>.video.decoder.avc.secure" type="video/avc" &gt;
    &lt;Limit name="concurrent-instances" max="4" /&gt;
&lt;/MediaCodec&gt;
&lt;MediaCodec name="OMX.<em>&lt;vendor&gt;</em>.video.decoder.mpeg4" type="video/mp4v-es" &gt;
    &lt;Limit name="concurrent-instances" max="12" /&gt;
&lt;/MediaCodec&gt;
&lt;MediaCodec name="OMX.<em>&lt;vendor&gt;</em>.video.decoder.h263" type="video/3gpp" &gt;
    &lt;Limit name="concurrent-instances" max="12" /&gt;
&lt;/MediaCodec&gt;
&lt;MediaCodec name="OMX.<em>&lt;vendor&gt;</em>.video.decoder.vp8" type="video/x-vnd.on2.vp8" &gt;
    &lt;Limit name="concurrent-instances" max="12" /&gt;
&lt;/MediaCodec&gt;
</pre>

    <li>Add the <code>concurrent-instances</code> lines suggested in the test
failure message to the <code>/etc/media_codecs.xml</code> file.

    <li>Re-run the test to verify its success.
  </ol>

<h2 id=2_achievable_frame_rates_for_video_codecs>2. Achievable frame rates for video codecs</h2>
<p>The <code>VideoCapabilities.getAchievableFrameRatesFor</code> interface
returns the range of achievable video frame rates for a video size. This
information must be provided by the OEM for each device via an XML file placed at
<code>/etc/media_codecs_performance.xml</code>. These settings are tested by
the <code>com.android.cts.videoperf.VideoEncoderDecoderTest</code> and
<code>android.media.cts.VideoDecoderPerfTest</code> CTS tests.</p>

<p>OEMs can use the CTS tests to generate the XML files that pass the tests. To do this:</p>
  <ol>
    <li>Run the tests first using cts-tradefed. Given the
variability of Android performance, it is recommended the tests are run
multiple times to get more accurate minimum and maximum values.
    <li>Use the provided <a
href="https://android.googlesource.com/platform/cts/+/marshmallow-cts-dev/tools/cts-media/get_achievable_rates.py">get_achievable_rates.py</a>
script to generate the XML file.
    <li>Place the XML file at: <code>/etc/media_codecs_performance.xml</code><br>
This is usually done by placing the XML file in the device project
(device/<em>&lt;vendor&gt;</em>/<em>&lt;product&gt;</em>) and adding a
<code>PRODUCT_COPY_FILES</code> line to <code>device.mk</code> like so:
<pre>
PRODUCT_COPY_FILES += \
...
   device/moto/shamu/media_codecs.xml:system/etc/media_codecs.xml \
+    device/moto/shamu/media_codecs_performance.xml:system/etc/media_codecs_performance.xml
</pre>
    <li>Re-run the performance tests to verify their success.
  </ol>

<h2 id=3_co-exist_of_secure_codec_and_non-secure_codec>3. Co-exist of secure codec and non-secure codec</h2>

<ul>
  <li>supports-secure-with-non-secure-codec &mdash;
If the instance of secure codec and the instance of non-secure codec can’t
co-exist at the same time, that should be indicated as global setting in the
<code>media_codecs.xml</code> file.
<pre>
&lt;MediaCodecs&gt;
    &lt;Settings&gt;
        &lt;Setting name="supports-secure-with-non-secure-codec" value="false" /&gt;
    &lt;/Settings&gt;
    &lt;Encoders&gt;
…
</pre>
  <li>supports-multiple-secure-codecs &mdash;
If co-exist of multiple secure codec instances is not supported, that should be
indicated as a global setting in the <code>media_codecs.xml</code> file.
<pre>
&lt;MediaCodecs&gt;
    &lt;Settings&gt;
        &lt;Setting name="supports-multiple-secure-codecs" value="false" /&gt;
    &lt;/Settings&gt;
    &lt;Encoders&gt;
…
</pre>
  <li>Note that the both settings are true by default, meaning if they are supported,
there’s no need to add the setting line to the <code>media_codecs.xml</code>.
  <li>The <code>ResourceManagerTest</code> CTS tests may fail if these two settings were not set
properly.
</ul>