OboeTester can be used to measure the round trip latency and glitches. It can be launched from a shell script by using an Android Intent.
Before running the app from an Intent, it should be launched manually and a Round Trip Latency test run. Then you can give permission for using the microphone to record the looped back sound, and give permission to write to external storage for saving the test result.
* If you don't have a 3.5 mm jack then you can use a USB-C to 3.5mm adapter. Then you will also need a USB switching device such as TigerTail.
The app can be started by sending a Start comment to the OboeTester class. The app will run and the results will be written to a file.
adb shell am start -n com.google.sample.oboe.manualtest/.MainActivity {parameters}
String parameters are sent using:
--es {parameterName} {parameterValue}
For example:
--es test latency
Integer parameters are sent using:
--ei {parameterName} {parameterValue}
For example:
--ei buffer_bursts 8
There are two required parameters:
--es test {latency, glitch}
The "latency" test will perform a Round Trip Latency test.
It will request EXCLUSIVE mode for minimal latency.
The "glitch" test will perform a single Glitch test.
--es file {full path for resulting file}
There are several optional parameter in common for all tests:
--ei buffer_bursts {bursts} // number of bursts in the buffer, 2 for "double buffered"
--es in_api {"unspecified", "opensles", "aaudio"} // native input API, default is "unspecified"
--es out_api {"unspecified", "opensles", "aaudio"} // native output API, default is "unspecified"
--ei in_channels {samples} // number of input channels, default is 2
--ei out_channels {samples} // number of output channels, default is 2
--ei sample_rate {hertz}
--es in_perf {"none", "lowlat", "powersave"} // input performance mode, default is "lowlat"
--es out_perf {"none", "lowlat", "powersave"} // output performance mode, default is "lowlat"
--es in_sharing {"shared", "exclusive"} // input sharing mode, default is "exclusive"
--es out_sharing {"shared", "exclusive"} // output sharing mode, default is "exclusive"
There are several optional parameters for just the “glitch” test:
--ef tolerance {tolerance} // amount of deviation from expected that is considered a glitch
// Range of tolerance is 0.0 to 1.0. Default is 0.1. Note use of "-ef".
--ei duration {seconds} // glitch test duration, default is 10 seconds
// input preset, default is "voicerec"
--es in_preset ("generic", "camcorder", "voicerec", "voicecomm", "unprocessed", "performance"}
For example, a complete command for a “latency” test might be:
adb shell am start -n com.google.sample.oboe.manualtest/.MainActivity \
--es test latency \
--es file /sdcard/latency20190903.txt \
--ei buffer_bursts 2 \
--ei out_channels 1
or for a “glitch” test:
adb shell am start -n com.google.sample.oboe.manualtest/.MainActivity \
--es test glitch \
--es file /sdcard/glitch20190903.txt \
--es in_perf lowlat \
--es out_perf lowlat \
--es in_sharing exclusive \
--es out_sharing exclusive \
--ei buffer_bursts 2 \
--ei sample_rate 48000 \
--ef tolerance 0.123 \
--ei in_channels 2 \
Test results are simple files with “name = value” pairs. The test results can be obtained using adb pull.
adb pull /sdcard/test20190611.txt .
The beginning of the report is common to all tests:
build.fingerprint = google/bonito/bonito:10/QP1A.190711.017/5771233:userdebug/dev-keys test.version = 1.5.10 test.version.code = 19 time.millis = 1567521906542 in.channels = 2 in.perf = lowlat in.sharing = exclusive in.api = aaudio in.rate = 48000 in.device = 30 in.mmap = yes in.burst.frames = 96 in.xruns = 0 out.channels = 2 out.perf = lowlat out.sharing = exclusive out.api = aaudio out.rate = 48000 out.device = 27 out.mmap = yes out.burst.frames = 96 out.buffer.size.frames = 192 out.buffer.capacity.frames = 3072 out.xruns = 0
Each test also adds specific value. For “latency”. If the test fails then some values will be unavailable.
Here is a report from a good test. The ‘#’ comments were added for this document and are not in the report.
rms.signal = 0.81829 # Root Mean Square of the signal, if it can be detected rms.noise = 0.12645 # Root Mean Square of the background noise before the signal is detected reset.count = 2 # number of times the full duplex stream input underflowed and had to resynchronize result = 0 # 0 or a negative error result.text = OK # text equivalent of the result latency.empty.frames = 476 # round trip latency if the top output buffer was empty latency.empty.msec = 9.92 # same but translated to milliseconds latency.frames = 668 # round trip latency as measured latency.msec = 13.92 # same but translated to milliseconds, "pro-audioo" devices should be <=20 msec confidence = 0.959 # quality of the latency result between 0.0 and 1.0, higher is better
Here is a report from a test that failed because the output was muted. Note the latency.msec is missing because it could not be measured.
rms.signal = 0.00000 rms.noise = 0.00048 reset.count = 3 result = -96 result.text = ERROR_CONFIDENCE confidence = 0.009
Here is a report from a good test. The ‘#’ comments were added for this document and are not in the report.
tolerance = 0.123 state = LOCKED unlocked.frames = 2528 # frames spent trying to lock onto the signal locked.frames = 384084 # frames spent locked onto a good signal with no glitches glitch.frames = 0 # frames spent glitching or recovering from a glitch reset.count = 208 # number of times the full duplex stream input underflowed and had to resynchronize peak.amplitude = 0.057714 # peak amplitude of the input signal, between 0.0 and 1.0 signal.noise.ratio.db = 96.3 time.total = 9.96 seconds # close to your specified duration time.no.glitches = 9.96 # time we have been running with no glitches max.time.no.glitches = 9.96 # max time with no glitches glitch.count = 0 # number of glitch events, actual number may be higher if close together
Here is a report from a test that failed because the output was muted. Note the glitch.count is missing because it could not be measured.
state = WAITING_FOR_SIGNAL unlocked.frames = 0 locked.frames = 0 glitch.frames = 0 reset.count = 1 time.total = 9.95 seconds