AirPlay: moveback to simplified sync - release

components/squeezelite/decode_external.c

@@ -50,7 +50,7 @@ static bool enable_airplay;
 static raop_event_t	raop_state;
 
 static EXT_RAM_ATTR struct {
-	bool enabled, init;
+	bool enabled;
 	int sum, count, win, errors[SYNC_WIN_SLOW];
 	s32_t len;
 	u32_t start_time, playtime;
@@ -181,21 +181,6 @@ static void raop_sink_data_handler(const uint8_t *data, uint32_t len, u32_t play
 	sink_data_handler(data, len);
 }	
 
-/****************************************************************************************
- * AirPlay apply sync
- */
-static void resync(int error) {
-	if (error < 0) {
-		output.skip_frames = -(error * RAOP_SAMPLE_RATE) / 1000;
-		output.state = OUTPUT_SKIP_FRAMES;					
-		LOG_INFO("skipping %u frames (count:%d)", output.skip_frames, raop_sync.count);
-	} else {
-		output.pause_frames = (error * RAOP_SAMPLE_RATE) / 1000;
-		output.state = OUTPUT_PAUSE_FRAMES;
-		LOG_INFO("pausing for %u frames (count: %d)", output.pause_frames, raop_sync.count);
-	}
-}	
-
 /****************************************************************************************
  * AirPlay sink command handler
  */
@@ -214,55 +199,52 @@ static bool raop_sink_cmd_handler(raop_event_t event, va_list args)
 	// this is async, so player might have been deleted
 	switch (event) {
 		case RAOP_TIMING: {
-			u32_t ms, now = gettime_ms();
-			int error;
 									
 			if (!raop_sync.enabled || output.state != OUTPUT_RUNNING || output.frames_played_dmp < output.device_frames) break;
-			
-			// do one (only one) time-based adjustement in case we started totally off)
-			if (raop_sync.init) {
-				// how many ms have we really played
-				ms = now - output.updated + ((output.frames_played_dmp - output.device_frames) * 10) / (RAOP_SAMPLE_RATE / 100);
-				error = ms - (now - raop_sync.start_time);
-				resync(error);
-											
-				LOG_INFO("backend played %u, desired %u, (delta:%d)", ms, now - raop_sync.start_time, error);
-					
-				raop_sync.init = false;
-				raop_sync.win = SYNC_WIN_FAST;
-				raop_sync.sum = raop_sync.count = 0 ;
-				memset(raop_sync.errors, 0, sizeof(raop_sync.errors));
-			} else {	
-				u32_t level = _buf_used(outputbuf);
+
+			u32_t ms, now = gettime_ms();
+			u32_t level = _buf_used(outputbuf);
+			int error;
 				
-				// in how many ms will the most recent block play 
-				ms = (((s32_t)(level - raop_sync.len) / BYTES_PER_FRAME + output.device_frames + output.frames_in_process) * 10) / (RAOP_SAMPLE_RATE / 100) - (s32_t) (now - output.updated);
+			// in how many ms will the most recent block play 
+			ms = (((s32_t)(level - raop_sync.len) / BYTES_PER_FRAME + output.device_frames + output.frames_in_process) * 10) / (RAOP_SAMPLE_RATE / 100) - (s32_t) (now - output.updated);
 				
-				// when outputbuf is empty, it means we have a network black-out or something
-				error = level ? (raop_sync.playtime - now) - ms : 0;
+			// when outputbuf is empty, it means we have a network black-out or something
+			error = level ? (raop_sync.playtime - now) - ms : 0;
 				
-				if (loglevel == lDEBUG || !level) {
-					LOG_INFO("head local:%d, remote:%d (delta:%d)", ms, raop_sync.playtime - now, error);
-					LOG_INFO("obuf:%u, sync_len:%u, devframes:%u, inproc:%u", _buf_used(outputbuf), raop_sync.len, output.device_frames, output.frames_in_process);
-				}	
-			
-				// calculate sum, error and update sliding window
-				raop_sync.errors[raop_sync.count++ % raop_sync.win] = error;
-				raop_sync.sum += error;
-				error = raop_sync.sum / min(raop_sync.count, raop_sync.win);
+			if (loglevel == lDEBUG || !level) {
+				LOG_INFO("head local:%d, remote:%d (delta:%d)", ms, raop_sync.playtime - now, error);
+				LOG_INFO("obuf:%u, sync_len:%u, devframes:%u, inproc:%u", _buf_used(outputbuf), raop_sync.len, output.device_frames, output.frames_in_process);
+			}	
 			
-				// move to normal mode if possible
-				if (raop_sync.win == SYNC_WIN_FAST && raop_sync.count >= SYNC_WIN_FAST && abs(error) < 10) {
-					raop_sync.win = SYNC_WIN_SLOW;
-					LOG_INFO("switching to slow sync mode %u", raop_sync.win);
-				}	
+			// calculate sum, error and update sliding window
+			raop_sync.errors[raop_sync.count++ % raop_sync.win] = error;
+			raop_sync.sum += error;
+			error = raop_sync.sum / min(raop_sync.count, raop_sync.win);
 
-				// wait till we have enough data or there is a strong deviation
-				if ((raop_sync.count >= raop_sync.win && abs(error) > 10) || (raop_sync.count >= SYNC_WIN_CHECK && abs(error) > 100)) {
-					resync(error);
-					raop_sync.sum = raop_sync.count = 0;
-					memset(raop_sync.errors, 0, sizeof(raop_sync.errors));
-				}	
+			// wait till we have enough data or there is a strong deviation
+			if ((raop_sync.count >= raop_sync.win && abs(error) > 10) || (raop_sync.count >= SYNC_WIN_CHECK && abs(error) > 100)) {
+				if (error < 0) {
+					output.skip_frames = -(error * RAOP_SAMPLE_RATE) / 1000;
+					output.state = OUTPUT_SKIP_FRAMES;					
+					LOG_INFO("skipping %u frames (count:%d)", output.skip_frames, raop_sync.count);
+				} else {
+					output.pause_frames = (error * RAOP_SAMPLE_RATE) / 1000;
+					output.state = OUTPUT_PAUSE_FRAMES;
+					LOG_INFO("pausing for %u frames (count: %d)", output.pause_frames, raop_sync.count);
+				}
+				
+				raop_sync.sum = raop_sync.count = 0;
+				memset(raop_sync.errors, 0, sizeof(raop_sync.errors));
+			}	
+			
+			// move to normal mode if possible			
+			if (raop_sync.win == 1) {
+				raop_sync.win = SYNC_WIN_FAST;
+				LOG_INFO("backend played %u, desired %u, (delta:%d)", ms, raop_sync.playtime - now, error);
+			} else if (raop_sync.win == SYNC_WIN_FAST && raop_sync.count >= SYNC_WIN_FAST && abs(error) < 10) {
+				raop_sync.win = SYNC_WIN_SLOW;
+				LOG_INFO("switching to slow sync mode %u", raop_sync.win);
 			}	
 
 			break;
@@ -279,7 +261,9 @@ static bool raop_sink_cmd_handler(raop_event_t event, va_list args)
 		case RAOP_STREAM:
 			LOG_INFO("Stream", NULL);
 			raop_state = event;
-			raop_sync.init = true;
+			raop_sync.win = 1;
+			raop_sync.sum = raop_sync.count = 0;
+			memset(raop_sync.errors, 0, sizeof(raop_sync.errors));
 			raop_sync.enabled = !strcasestr(output.device, "BT");
 			output.next_sample_rate = output.current_sample_rate = RAOP_SAMPLE_RATE;
 			break;