demux: adaptative: fix mp4 seek after streamdemux restart

modules/demux/adaptative/plumbing/Demuxer.cpp

@@ -51,6 +51,11 @@ StreamDemux::StreamDemux(demux_t *p_realdemux_, const std::string &name_, es_out
     name = name_;
     p_realdemux = p_realdemux_;
 
+    if(name == "mp4")
+    {
+        b_startsfromzero = true;
+    }
+
     restart();
 
     if(!demuxstream)

modules/demux/adaptative/plumbing/StreamOutput.cpp

@@ -121,6 +121,10 @@ void BaseStreamOutput::setPosition(mtime_t nztime)
         restart();
         fakeesout->commandsqueue.Abort( true );
         fakeesout->recycleAll();
+        /* Check if we need to set an offset as the demuxer
+         * will start from zero from seek point */
+        if(demuxer->alwaysStartsFromZero())
+            fakeesout->setTimestampOffset(nztime);
     }
 
     es_out_Control(realdemux->out, ES_OUT_SET_NEXT_DISPLAY_TIME,