Chromium Code Reviews Chromium Code Reviews
Issue 2996233004:
Port a media metric to TBMv2 (Closed)
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| 1 <!DOCTYPE html> | |
| 2 <!-- | |
| 3 Copyright 2017 The Chromium Authors. All rights reserved. | |
| 4 Use of this source code is governed by a BSD-style license that can be | |
| 5 found in the LICENSE file. | |
| 6 --> | |
| 7 | |
| 8 <!-- | |
| 9 media_metrics uses Chrome trace events to calculate metrics about video | |
| 10 and audio playback. It is meant to be used for pages with a <video> or | |
| 11 <audio> element. It is used by videostack-eng@google.com team for | |
| 12 regression testing. | |
| 13 | |
| 14 This metric currently supports the following measurement: | |
| 15 * time_to_play calculates how long after a video is requested to | |
| 16 start playing before the video actually starts. If time_to_play | |
| 17 regresses, then users will click to play videos and then have | |
| 18 to wait longer before the videos start actually playing. | |
| 19 | |
| 20 More measurements are expected to be added in the near future, such as: | |
| 21 * buffering_time | |
| 22 * seek_time | |
| 23 * dropped_frame_count | |
| 24 | |
| 25 Please inform crouleau@chromium.org and johnchen@chromium.org about | |
| 26 changes to this file. | |
| 27 --> | |
| 28 | |
| 29 <link rel="import" href="/tracing/metrics/metric_registry.html"> | |
| 30 <link rel="import" href="/tracing/model/helpers/chrome_model_helper.html"> | |
| 31 <link rel="import" href="/tracing/value/histogram.html"> | |
| 32 | |
| 33 <script> | |
| 34 'use strict'; | |
| 35 | |
| 36 tr.exportTo('tr.metrics', function() { | |
| 37 function mediaMetric(histograms, model) { | |
| 38 let playStart; | |
| 39 let timeToPlay; | |
| 40 | |
| 41 const chromeHelper = model.getOrCreateHelper( | |
| 42 tr.model.helpers.ChromeModelHelper); | |
| 43 if (chromeHelper === undefined) return; | |
| 44 for (const rendererHelper of Object.values(chromeHelper.rendererHelpers)) { | |
| 45 for (const event of rendererHelper.process.getDescendantEvents()) { | |
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benjhayden
2017/08/29 23:17:25
Thanks, this is good, keep going.
Which thread[s]
johnchen
2017/08/30 01:39:19
The code now looks for the events on specific thre
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| 46 if (event.title === 'WebMediaPlayerImpl::DoLoad') { | |
| 47 if (playStart === undefined) { | |
| 48 playStart = event.start; | |
| 49 } | |
| 50 } else if (event.title === 'VideoRendererImpl::Render' || | |
| 51 event.title === 'AudioRendererImpl::Render') { | |
| 52 if (playStart !== undefined && timeToPlay === undefined) { | |
| 53 timeToPlay = event.start - playStart; | |
| 54 break; | |
|
benjhayden
2017/08/29 23:17:25
We try to make metrics as general as possible in o
johnchen
2017/08/30 01:39:19
The Render events are raised for each video frame.
| |
| 55 } | |
| 56 } | |
| 57 } | |
| 58 if (timeToPlay !== undefined) { | |
| 59 break; | |
| 60 } | |
| 61 } | |
| 62 | |
| 63 if (timeToPlay !== undefined) { | |
| 64 histograms.createHistogram('time_to_play', | |
| 65 tr.b.Unit.byName.timeDurationInMs_smallerIsBetter, timeToPlay); | |
| 66 } | |
| 67 } | |
| 68 | |
| 69 tr.metrics.MetricRegistry.register(mediaMetric); | |
| 70 | |
| 71 return { | |
| 72 mediaMetric, | |
| 73 }; | |
| 74 }); | |
| 75 </script> | |
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