Changes between Version 2 and Version 3 of MeasuringSoundLatency
- Timestamp:
- Jul 28, 2008 11:24:45 AM (16 years ago)
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MeasuringSoundLatency
v2 v3 8 8 * [http://www.pjsip.org/pjsua.htm pjsua] 9 9 * a computer with microphone and loudspeaker (not headset) 10 * [file:tock8.wav]WAV file attached.10 * {{{tock8.wav}}} WAV file attached. 11 11 * a WAV waveform display/analyzer to visually see the latency (such as Cool Edit on Windows) 12 * or {{{latency.c}}} file if you don't have WAV waveform analyzer program. This file is included in PJSIP version 0.9.5 and later in {{{pjsip-apps/src/samples}}} directory, or if you use older PJSIP you can find the [file:latency.c]file attached.12 * or {{{latency.c}}} file if you don't have WAV waveform analyzer program. This file is included in PJSIP version 0.9.5 and later in {{{pjsip-apps/src/samples}}} directory, or if you use older PJSIP you can find the {{{latency.c}}} file attached. 13 13 14 14 == Setup == … … 62 62 Here's what the recorded signal ({{{rec1.wav}}}) looks like in my WAV analyzer: 63 63 64 [[Image(rec1. png)]]64 [[Image(rec1.PNG, 50%)]] 65 65 66 66 The highlighted area in above picture shows one recording of both original signal and the echo. … … 68 68 If we zoom-in the highlighted area, it will look like this: 69 69 70 [[Image(rec1-zoom. png)]]70 [[Image(rec1-zoom.PNG, 50%)]] 71 71 72 72 And to find out the latency, just measure the interval between original signal and echoed signal: 73 73 74 [[Image(rec1-latency. png)]]74 [[Image(rec1-latency.PNG, 50%)]] 75 75 76 76 In this test, I found out that the latency is approximately 171 milliseconds.