Source code
Revision control
Copy as Markdown
Other Tools
# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
import filters
from base_python_support import BasePythonSupport
class VideoPlaybackLatency(BasePythonSupport):
def __init__(self, **kwargs):
super().__init__(**kwargs)
self._is_android = False
self._is_chrome = False
def setup_test(self, test, args):
from cmdline import CHROME_ANDROID_APPS, CHROMIUM_DISTROS, DESKTOP_APPS
self._is_android = args.app not in DESKTOP_APPS
self._is_chrome = (
args.app in CHROMIUM_DISTROS or args.app in CHROME_ANDROID_APPS
)
def modify_command(self, cmd, test):
# Because of the aspect ratio of Android during recording,
# most pixels are white, so we need to use a lower fraction.
fraction = "0.25" if self._is_android else "0.7"
# Firefox/Safari configuration allows video playback but
# Chrome needs an explicit switch to enable it.
if self._is_chrome:
cmd += [
"--chrome.enableVideoAutoplay",
"true",
]
cmd += [
"--visualMetricsKeyColor",
"poster",
"0",
"128",
"220",
"255",
"220",
"255",
fraction,
"--visualMetricsKeyColor",
"firstFrame",
"220",
"255",
"0",
"60",
"0",
"60",
fraction,
"--visualMetricsKeyColor",
"secondFrame",
"0",
"60",
"0",
"60",
"220",
"255",
fraction,
"--visualMetricsKeyColor",
"lastFrame",
"220",
"255",
"220",
"255",
"0",
"128",
fraction,
]
def handle_result(self, bt_result, raw_result, last_result=False, **kwargs):
measurements = {
"poster": [],
"posterEnd": [],
"firstFrame": [],
"secondFrame": [],
"lastFrame": [],
"estimatedFirstFrameLatency": [],
"estimatedAnyFrameLatency": [],
}
fps = 30.0
total_duration_ms = 1000.0
frame_duration_ms = total_duration_ms / fps
offsets = {
"firstFrame": 0.0,
"posterEnd": 0.0,
"secondFrame": frame_duration_ms * 3.0,
"lastFrame": total_duration_ms - frame_duration_ms,
}
# Gather the key frame start times of each page/cycle
for cycle in raw_result["visualMetrics"]:
measurement = {}
for key, frames in cycle["KeyColorFrames"].items():
if key not in measurements or not len(frames):
continue
measurement[key] = frames[0]["startTimestamp"]
if key == "poster":
measurement["posterEnd"] = frames[0]["endTimestamp"]
for key in ["firstFrame", "posterEnd", "secondFrame", "lastFrame"]:
if key not in measurement:
continue
normalized_value = measurement[key] - offsets[key]
if normalized_value <= 0:
continue
measurements["estimatedFirstFrameLatency"].append(normalized_value)
break
for key, value in measurement.items():
measurements[key].append(value)
if key not in offsets:
continue
normalized_value = value - offsets[key]
if normalized_value <= 0:
continue
measurements["estimatedAnyFrameLatency"].append(normalized_value)
for measurement, values in measurements.items():
bt_result["measurements"].setdefault(measurement, []).extend(values)
def _build_subtest(self, measurement_name, replicates, test):
unit = test.get("unit", "ms")
if test.get("subtest_unit"):
unit = test.get("subtest_unit")
return {
"name": measurement_name,
"lowerIsBetter": test.get("lower_is_better", True),
"alertThreshold": float(test.get("alert_threshold", 2.0)),
"unit": unit,
"replicates": replicates,
"value": round(filters.geometric_mean(replicates), 3),
}
def summarize_test(self, test, suite, **kwargs):
suite["type"] = "pageload"
if suite["subtests"] == {}:
suite["subtests"] = []
for measurement_name, replicates in test["measurements"].items():
if not replicates:
continue
suite["subtests"].append(
self._build_subtest(measurement_name, replicates, test)
)
suite["subtests"].sort(key=lambda subtest: subtest["name"])