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Fix the sleep logic for streaming as per sample rate #279

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merged 11 commits into from
Aug 4, 2016
Merged

Fix the sleep logic for streaming as per sample rate #279

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80eb6da
sleep 100ms instead of sleeping as function of rate
puneithk Jul 28, 2016
7d8f4b5
added sleep as inverse of sampling rate
puneithk Jul 29, 2016
d87d691
added LINEAR16 bytes per sample constant
puneithk Jul 29, 2016
ff7ffbc
added few variables
puneithk Jul 29, 2016
a23abdc
added truth and log4j
puneithk Aug 4, 2016
0cee557
added 32khz audio
puneithk Aug 4, 2016
df11062
added Streaming Test
puneithk Aug 4, 2016
a253ebf
added unit tests for 16 and 32 khz audio
puneithk Aug 4, 2016
d1fdc61
checkstyle fixes
puneithk Aug 4, 2016
a44e692
renamed to KHz
puneithk Aug 4, 2016
4ac456e
added comment
puneithk Aug 4, 2016
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4 changes: 2 additions & 2 deletions speech/grpc/src/main/java/com/examples/cloud/speech/StreamingRecognizeClient.java
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Original file line number Diff line number Diff line change
Expand Up @@ -138,8 +138,8 @@ public void onCompleted() {
.build();
requestObserver.onNext(request);
// To simulate real-time audio, sleep after sending each audio buffer.
// For 16000 Hz sample rate, sleep 100 milliseconds.
Thread.sleep(samplingRate / 160);
// Sleep 100ms
Thread.sleep(100);
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Approximating realtime is dependent on the samplingRate, so you can't hard-code 100ms unless you're also hard-coding the samplingRate.

The calculation here should instead be dependent on samplingRate, buffer size, and encoding. Since encoding is hard-coded to 2 bytes per sample, you should sleep for:

int BYTES_PER_SAMPLE = 2;  // because LINEAR16 - ie 16 bits per sample, at 8 bits per byte
int BYTES_PER_BUFFER = 3200;
int SAMPLES_PER_BUFFER = BYTES_PER_BUFFER / BYTES_PER_SAMPLE; // 1600

int samplesPerMillisecond = samplingRate / 1000;
int millisecondsPerBuffer = SAMPLES_PER_BUFFER / samplesPerMillisecond;
Thread.sleep(millisecondsPerBuffer);

which for 16000 Hz is 1600 / 16 = 100 (as expected), and for 32000 Hz is 1600 / 32 = 50 (which is faster than the original 32000 / 160 = 200). I suspect there was just an error in the original calculation. (feel free to check my math as well - but at least it gives a shorter sleep duration, which is what you'd expect if you increase the sample rate while keeping the buffer size the same)

}
logger.info("Sent " + totalBytes + " bytes from audio file: " + file);
} catch (RuntimeException e) {
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