Fix on-demand playback timing drift: use absolute timing instead of sleep(0.058) to prevent audio cuts on long files

bridge_master.py

@@ -790,16 +790,22 @@ def playFileOnRequest(self,fileNumber):
     speech = pkt_gen(_source_id, _nine, bytes_4(9), 1, _say)
     sleep(1)
     _slot  = systems[system].STATUS[2]
+    _next_time = time()
+    _pkt_count = 0
     while True:
         try:
             pkt = next(speech)
         except StopIteration:
                 break
-        sleep(0.058)
+        _next_time += 0.058
+        _delay = _next_time - time()
+        if _delay > 0.001:
+            sleep(_delay)
         _stream_id = pkt[16:20]
         _pkt_time = time()
         reactor.callFromThread(sendVoicePacket,self,pkt,_source_id,_nine,_slot)
-    logger.info('(%s) On-demand playback complete: %s', system, fileNumber)
+        _pkt_count += 1
+    logger.info('(%s) On-demand playback complete: %s (%d packets)', system, fileNumber, _pkt_count)
 
 def threadIdent():
     logger.debug('(IDENT) starting ident thread')