docs/html/preview/features/tv-recording-api.jd

page.title=TV Recording
page.keywords=preview,sdk,tv,recording
page.tags=androidn
page.image=images/cards/card-nyc_2x.jpg

@jd:body

<div id="qv-wrapper">
<div id="qv">
  <h2>In this document</h2>
  <ol>
    <li><a href="#supporting">Indicating Support for Recording</a></li>
    <li><a href="#recording">Recording a Session</a></li>
    <li><a href="#errors">Handling Recording Errors</a></li>
    <li><a href="#sessions">Managing Recorded Sessions</a></li>
    <li><a href="#best">Best Practices</a></li>
  </ol>
</div>
</div>

<p>TV input services let the user pause and resume channel playback via
time-shifting APIs. Android N expands on time-shifting
by letting the user save multiple recorded sessions.</p>

<p>Users can schedule recordings in advance, or start a recording as they watch
a program. Once the system has saved a recording, the user can browse, manage,
and play back the recording using the system TV app.</p>

<p>If you want to provide recording functionality for your TV input service,
you must indicate to the system that your app supports recording, implement
the ability to record programs, handle and communicate any errors that occur
during recording, and manage your recorded sessions.</p>

<p class="note"><strong>Note:</strong> The Live Channels app does not yet
provide a way for users to create or access recordings. Until changes are
made to the Live Channels app, it may be difficult to fully test the recording
experience for your TV input service.</p>

<h2 id="supporting">Indicating Support for Recording</h2>

<p>To tell the system that your TV input service supports recording, set
the <code>android:canRecord</code> attribute in your service metadata XML file
to <code>true</code>:
</p>

<pre>
&lt;tv-input xmlns:android="http://schemas.android.com/apk/res/android"
  <b>android:canRecord="true"</b>
  android:setupActivity="com.example.sampletvinput.SampleTvInputSetupActivity" /&gt;
</pre>

<p>For more information on the service metadata file, see
<a href="{@docRoot}training/tv/tif/tvinput.html#manifest">Declare Your TV Input
Service in the Manifest</a>.
</p>

<p>Alternatively, you can indicate recording support in your code using
these steps:</p>

<ol>
<li>In your <code>TvInputService.onCreate()</code> method, create a new
<code>TvInputInfo</code> object using the <code>TvInputInfo.Builder</code>
class.</li>
<li>When creating the new <code>TvInputInfo</code> object, call
<code>setCanRecord(true)</code> before calling <code>build()</code> to
indicate your service supports recording.</li>
<li>Register your <code>TvInputInfo</code> object with the system by calling
<code>TvInputManager.updateTvInputInfo()</code>.</li>
</ol>

<h2 id="recording">Recording a Session</h2>

<p>After your TV input service registers that it supports recording
functionality, the system calls your
<code>TvInputService.onCreateRecordingSession()</code> when it needs to access
your app's recording implementation. Implement your own
<code>TvInputService.RecordingSession</code> subclass and return it
when the <code>onCreateRecordingSession()</code> callback
fires. This subclass is responsible for switching to the correct channel data,
recording the requested data, and communicating recording status and errors to
the system.</p>

<p>When the system calls <code>RecordingSession.onTune()</code>, passing in a
channel URI, tune to the channel that the URI specifies. Notify the system that
your app has tuned to the desired channel by calling <code>notifyTuned()</code>,
or, if your app could not tune to the proper channel, call
<code>notifyError()</code>.</p>

<p>The system next invokes the <code>RecordingSession.onStartRecording()</code>
callback. Your app must start recording immediately. When the system invokes
this callback, it may provide a URI that contains information about the program
that is about to be recorded. When the recording is done, you need to copy this
data to the <code>RecordedPrograms</code> data table.</p>

<p>Finally, the system calls <code>RecordingSession.onStopRecording()</code>.
At this point, your app must stop recording immediately. You also need to
create an entry in the <code>RecordedPrograms</code> table. This entry should
include the recorded session data URI in the
<code>RecordedPrograms.COLUMN_RECORDING_DATA_URI</code> column, and any program
information that the system provided in the initial call to
<code>onStartRecording()</code>.</p>

<p>For more details on how to access the <code>RecordedPrograms</code> table
see <a href="#sessions">Managing Recorded Sessions</a>.</p>

<h2 id="errors">Handling Recording Errors</h2>

<p>If an error occurs during recording, rendering the recorded data unusable,
notify the system by calling <code>RecordingSession.notifyError()</code>.
Similarly, you can call <code>notifyError()</code> after a recording session is
created to let the system know that your app can no longer record sessions.</p>

<p>If an error occurs during recording, but you'd like to provide a usable
partial recording to users for playback, call
<code>RecordingSession.notifyRecordingStopped()</code> to enable the system to
use the partial session.</p>

<h2 id="sessions">Managing Recorded Sessions</h2>

<p>The system maintains information for all recorded sessions from all
recording-capable channel apps in the <code>TvContract.RecordedPrograms</code>
content provider table. This information is accessible via the
<code>RecordedPrograms.Uri</code> content URI. Use content provider APIs to
read, add, and delete entries from this table.</p>

<p>For more information on working with content provider data see
<a href="{@docRoot}guide/topics/providers/content-provider-basics.html">
Content Provider Basics</a> .</p>

<h2 id="best">Best Practices</h2>

<p>TV devices may have limited storage, so use your best judgment when
allocating storage to save recorded sessions. Use
<code>RecordingCallback.onError(RECORDING_ERROR_INSUFFICIENT_SPACE)</code> when
there isn't enough space to save a recorded session.</p>

<p>When the user initiates recording, you should start recording data as soon
as possible. To facilitate this, complete any up-front time-consuming tasks,
like accessing and allocating storage space, when the system invokes the
<code>onCreateRecordingSession()</code> callback. Doing so lets you start
recording immediately when the <code>onStartRecording()</code> callback
fires.</p>