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<html><head><title>Python: module telemetry.web_perf.metrics.smoothness</title>
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<font color="#ffffff" face="helvetica, arial"> <br><big><big><strong><a href="telemetry.html"><font color="#ffffff">telemetry</font></a>.<a href="telemetry.web_perf.html"><font color="#ffffff">web_perf</font></a>.<a href="telemetry.web_perf.metrics.html"><font color="#ffffff">metrics</font></a>.smoothness</strong></big></big></font></td
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><font color="#ffffff" face="helvetica, arial"><a href=".">index</a><br><a href="../telemetry/web_perf/metrics/smoothness.py">telemetry/web_perf/metrics/smoothness.py</a></font></td></tr></table>
<p><tt># Copyright 2014 The Chromium Authors. All rights reserved.<br>
# Use of this source code is governed by a BSD-style license that can be<br>
# found in the LICENSE file.</tt></p>
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<font color="#ffffff" face="helvetica, arial"><big><strong>Modules</strong></big></font></td></tr>
<tr><td bgcolor="#aa55cc"><tt> </tt></td><td> </td>
<td width="100%"><table width="100%" summary="list"><tr><td width="25%" valign=top><a href="telemetry.value.improvement_direction.html">telemetry.value.improvement_direction</a><br>
<a href="telemetry.value.list_of_scalar_values.html">telemetry.value.list_of_scalar_values</a><br>
</td><td width="25%" valign=top><a href="logging.html">logging</a><br>
<a href="telemetry.util.perf_tests_helper.html">telemetry.util.perf_tests_helper</a><br>
</td><td width="25%" valign=top><a href="telemetry.web_perf.metrics.rendering_stats.html">telemetry.web_perf.metrics.rendering_stats</a><br>
<a href="telemetry.value.scalar.html">telemetry.value.scalar</a><br>
</td><td width="25%" valign=top><a href="telemetry.util.statistics.html">telemetry.util.statistics</a><br>
<a href="telemetry.web_perf.metrics.timeline_based_metric.html">telemetry.web_perf.metrics.timeline_based_metric</a><br>
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<font color="#ffffff" face="helvetica, arial"><big><strong>Classes</strong></big></font></td></tr>
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<dt><font face="helvetica, arial"><a href="telemetry.web_perf.metrics.timeline_based_metric.html#TimelineBasedMetric">telemetry.web_perf.metrics.timeline_based_metric.TimelineBasedMetric</a>(<a href="__builtin__.html#object">__builtin__.object</a>)
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<dt><font face="helvetica, arial"><a href="telemetry.web_perf.metrics.smoothness.html#SmoothnessMetric">SmoothnessMetric</a>
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<font color="#000000" face="helvetica, arial"><a name="SmoothnessMetric">class <strong>SmoothnessMetric</strong></a>(<a href="telemetry.web_perf.metrics.timeline_based_metric.html#TimelineBasedMetric">telemetry.web_perf.metrics.timeline_based_metric.TimelineBasedMetric</a>)</font></td></tr>
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<td colspan=2><tt>Computes metrics that measure smoothness of animations over given ranges.<br>
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Animations are typically considered smooth if the frame rates are close to<br>
60 frames per second (fps) and uniformly distributed over the sequence. To<br>
determine if a timeline range contains a smooth animation, we update the<br>
results object with several representative metrics:<br>
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frame_times: A list of raw frame times<br>
mean_frame_time: The arithmetic mean of frame times<br>
percentage_smooth: Percentage of frames that were hitting 60 FPS.<br>
frame_time_discrepancy: The absolute discrepancy of frame timestamps<br>
mean_pixels_approximated: The mean percentage of pixels approximated<br>
queueing_durations: The queueing delay between compositor & main threads<br>
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Note that if any of the interaction records provided to AddResults have less<br>
than 2 frames, we will return telemetry values with None values for each of<br>
the smoothness metrics. Similarly, older browsers without support for<br>
tracking the BeginMainFrame events will report a ListOfScalarValues with a<br>
None value for the queueing duration metric.<br> </tt></td></tr>
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<td width="100%"><dl><dt>Method resolution order:</dt>
<dd><a href="telemetry.web_perf.metrics.smoothness.html#SmoothnessMetric">SmoothnessMetric</a></dd>
<dd><a href="telemetry.web_perf.metrics.timeline_based_metric.html#TimelineBasedMetric">telemetry.web_perf.metrics.timeline_based_metric.TimelineBasedMetric</a></dd>
<dd><a href="__builtin__.html#object">__builtin__.object</a></dd>
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Methods defined here:<br>
<dl><dt><a name="SmoothnessMetric-AddResults"><strong>AddResults</strong></a>(self, model, renderer_thread, interaction_records, results)</dt></dl>
<dl><dt><a name="SmoothnessMetric-__init__"><strong>__init__</strong></a>(self)</dt></dl>
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Methods inherited from <a href="telemetry.web_perf.metrics.timeline_based_metric.html#TimelineBasedMetric">telemetry.web_perf.metrics.timeline_based_metric.TimelineBasedMetric</a>:<br>
<dl><dt><a name="SmoothnessMetric-AddWholeTraceResults"><strong>AddWholeTraceResults</strong></a>(self, model, results)</dt><dd><tt>Computes and adds metrics corresponding to the entire trace.<br>
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Override this method to compute results that correspond to the whole trace.<br>
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Args:<br>
model: An instance of telemetry.timeline.model.TimelineModel.<br>
results: An instance of page.PageTestResults.</tt></dd></dl>
<dl><dt><a name="SmoothnessMetric-VerifyNonOverlappedRecords"><strong>VerifyNonOverlappedRecords</strong></a>(self, interaction_records)</dt><dd><tt>This raises exceptions if interaction_records contain overlapped ranges.</tt></dd></dl>
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Data descriptors inherited from <a href="telemetry.web_perf.metrics.timeline_based_metric.html#TimelineBasedMetric">telemetry.web_perf.metrics.timeline_based_metric.TimelineBasedMetric</a>:<br>
<dl><dt><strong>__dict__</strong></dt>
<dd><tt>dictionary for instance variables (if defined)</tt></dd>
</dl>
<dl><dt><strong>__weakref__</strong></dt>
<dd><tt>list of weak references to the object (if defined)</tt></dd>
</dl>
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<font color="#ffffff" face="helvetica, arial"><big><strong>Data</strong></big></font></td></tr>
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<td width="100%"><strong>NOT_ENOUGH_FRAMES_MESSAGE</strong> = "Not enough frames for smoothness metrics (at lea...der extremely slow<font color="#c040c0">\n</font>- Pages that can't be scrolled"</td></tr></table>
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