<div style="line-height:1.7;color:#000000;font-size:14px;font-family:arial">Hi, Ross,<div><span class="Apple-tab-span" style="white-space:pre"> </span>I saw the DeviceSource code in live555 project.</div><div><span class="Apple-tab-span" style="white-space:pre">      </span>I found that the the fPresentationTime would be set by gettimeofday when doGetNextFrame is called.</div><div><span class="Apple-tab-span" style="white-space:pre">   </span>I remembered you said the fPresentationTime must be same at the first time, <span style="line-height: 1.7;">       So how should it sync audio and video? </span></div><div><br></div></div><br><br><span title="neteasefooter"><span id="netease_mail_footer"></span></span>