tools/perf/metrics/media.py

   1 # Copyright 2013 The Chromium Authors. All rights reserved.
   2 # Use of this source code is governed by a BSD-style license that can be
   3 # found in the LICENSE file.
   4 import logging
   5 import os
   6
   7 from telemetry.value import list_of_scalar_values
   8 from telemetry.value import scalar
   9
  10 from metrics import Metric
  11
  12
  13 class MediaMetric(Metric):
  14   """MediaMetric class injects and calls JS responsible for recording metrics.
  15
  16   Default media metrics are collected for every media element in the page,
  17   such as decoded_frame_count, dropped_frame_count, decoded_video_bytes, and
  18   decoded_audio_bytes.
  19   """
  20
  21   def __init__(self, tab):
  22     super(MediaMetric, self).__init__()
  23     with open(os.path.join(os.path.dirname(__file__), 'media.js')) as f:
  24       js = f.read()
  25       tab.ExecuteJavaScript(js)
  26     self._results = None
  27     self._skip_basic_metrics = False
  28
  29   def Start(self, page, tab):
  30     """Create the media metrics for all media elements in the document."""
  31     if hasattr(page, 'skip_basic_metrics'):
  32       self._skip_basic_metrics = page.skip_basic_metrics
  33     tab.ExecuteJavaScript('window.__createMediaMetricsForDocument()')
  34
  35   def Stop(self, page, tab):
  36     self._results = tab.EvaluateJavaScript('window.__getAllMetrics()')
  37
  38   # Optional |exclude_metrics| args are not in base class Metric.
  39   # pylint: disable=W0221
  40   def AddResults(self, tab, results, exclude_metrics=None):
  41     """Reports all recorded metrics as Telemetry perf results."""
  42     exclude_metrics = exclude_metrics or []
  43     trace_names = []
  44     for media_metric in self._results:
  45       trace_names.append(self._AddResultsForMediaElement(media_metric, results,
  46                                                          exclude_metrics))
  47
  48     return '_'.join(trace_names) or tab.url
  49
  50   def _AddResultsForMediaElement(self, media_metric, results, exclude_metrics):
  51     """Reports metrics for one media element.
  52
  53     Media metrics contain an ID identifying the media element and values:
  54     media_metric = {
  55       'id': 'video_1',
  56       'metrics': {
  57           'time_to_play': 120,
  58           'decoded_bytes': 13233,
  59           ...
  60       }
  61     }
  62     """
  63     def AddOneResult(metric, unit):
  64       if metric in exclude_metrics:
  65         return
  66
  67       metrics = media_metric['metrics']
  68       for m in metrics:
  69         if m.startswith(metric):
  70           special_label = m[len(metric):]
  71           trace_name = '%s.%s%s' % (metric, trace, special_label)
  72           if isinstance(metrics[m], list):
  73             results.AddValue(list_of_scalar_values.ListOfScalarValues(
  74                 results.current_page, trace_name, unit,
  75                 values=[float(v) for v in metrics[m]],
  76                 important=True))
  77           else:
  78             results.AddValue(scalar.ScalarValue(
  79                 results.current_page, trace_name, unit, value=float(metrics[m]),
  80                 important=True))
  81
  82     trace = media_metric['id']
  83     if not trace:
  84       logging.error('Metrics ID is missing in results.')
  85       return
  86
  87     if not self._skip_basic_metrics:
  88       AddOneResult('buffering_time', 'ms')
  89       AddOneResult('decoded_audio_bytes', 'bytes')
  90       AddOneResult('decoded_video_bytes', 'bytes')
  91       AddOneResult('decoded_frame_count', 'frames')
  92       AddOneResult('dropped_frame_count', 'frames')
  93       AddOneResult('time_to_play', 'ms')
  94
  95     AddOneResult('avg_loop_time', 'ms')
  96     AddOneResult('seek', 'ms')
  97     return trace