[Inputs] Severely reduce metadata update intervals

The Vorbis, Opus, MAD MPEG, and especially the FFmpeg inputs needed to
have their metadata update intervals severely reduced, to reduce CPU
usage, especially on files with lots of tags. Interval reduced to only
once per second.

Signed-off-by: Christopher Snowhill <kode54@gmail.com>

Plugins/FFMPEG/FFMPEGDecoder.h

@@ -43,6 +43,9 @@ int64_t ffmpeg_seek(void *opaque, int64_t offset, int whence);
 	AVFrame *lastDecodedFrame;
 	AVPacket *lastReadPacket;
 
+	int metadataUpdateInterval;
+	int metadataUpdateCount;
+
 	BOOL metadataUpdated;
 
 	AudioChunk *prebufferedChunk;

Plugins/FFMPEG/FFMPEGDecoder.m

@@ -435,6 +435,9 @@ static uint8_t reverse_bits[0x100];
 	endOfStream = NO;
 	endOfAudio = NO;
 
+	metadataUpdateInterval = codecCtx->sample_rate;
+	metadataUpdateCount = 0;
+
 	if(rawDSD) {
 		totalFrames *= 8;
 	}
@@ -899,14 +902,18 @@ static void setDictionary(NSMutableDictionary *dict, NSString *tag, NSString *va
 		}
 	}
 
-	[self updateMetadata];
-
 	int framesReadNow = bytesRead / frameSize;
 	if(totalFrames && (framesRead + framesReadNow > totalFrames))
 		framesReadNow = (int)(totalFrames - framesRead);
 
 	framesRead += framesReadNow;
 
+	metadataUpdateCount += framesReadNow;
+	if(metadataUpdateCount >= metadataUpdateInterval) {
+		metadataUpdateCount -= metadataUpdateInterval;
+		[self updateMetadata];
+	}
+
 	id audioChunkClass = NSClassFromString(@"AudioChunk");
 	AudioChunk *chunk = [[audioChunkClass alloc] initWithProperties:[self properties]];
 	[chunk assignSamples:buffer frameCount:framesReadNow];

Plugins/MAD/MADDecoder.h

@@ -49,6 +49,9 @@
 	long framesToSkip;
 	int layer;
 
+	int metadataUpdateInterval;
+	int metadataUpdateCount;
+
 	NSString *genre;
 	NSString *album;
 	NSString *artist;

Plugins/MAD/MADDecoder.m

@@ -461,6 +461,11 @@
 			DLog(@"Decoding first frame: %i", r);
 		} while(r == 0);
 
+		if(r != -1) {
+			metadataUpdateInterval = sampleRate;
+			metadataUpdateCount = 0;
+		}
+
 		return (r == -1 ? NO : YES);
 	}
 
@@ -472,6 +477,9 @@
 		framesToSkip = _startPadding;
 	}
 
+	metadataUpdateInterval = sampleRate;
+	metadataUpdateCount = 0;
+
 	return ret;
 }
 
@@ -730,7 +738,11 @@
 		[self syncFormat];
 	}
 
-	[self updateMetadata];
+	metadataUpdateCount += chunk ? [chunk frameCount] : 0;
+	if(metadataUpdateCount >= metadataUpdateInterval) {
+		metadataUpdateCount -= metadataUpdateInterval;
+		[self updateMetadata];
+	}
 
 	// DLog(@"Read: %i/%i", bytesRead, size);
 	return chunk;

Plugins/Opus/Opus/OpusDecoder.h

@@ -23,6 +23,9 @@
 	int channels;
 	long totalFrames;
 
+	int metadataUpdateInterval;
+	int metadataUpdateCount;
+
 	NSDictionary *metaDict;
 	NSDictionary *icyMetaDict;
 

Plugins/Opus/Opus/OpusDecoder.m

@@ -129,6 +129,9 @@ opus_int64 sourceTell(void *_stream) {
 
 	[self updateMetadata];
 
+	metadataUpdateInterval = 48000;
+	metadataUpdateCount = 0;
+
 	return YES;
 }
 
@@ -269,7 +272,11 @@ static void setDictionary(NSMutableDictionary *dict, NSString *tag, NSString *va
 
 	} while(total != size && numread != 0);
 
-	[self updateIcyMetadata];
+	metadataUpdateCount += total / channels;
+	if(metadataUpdateCount >= metadataUpdateInterval) {
+		metadataUpdateCount -= metadataUpdateInterval;
+		[self updateIcyMetadata];
+	}
 
 	id audioChunkClass = NSClassFromString(@"AudioChunk");
 	AudioChunk *chunk = [[audioChunkClass alloc] initWithProperties:[self properties]];

Plugins/Vorbis/VorbisDecoder.h

@@ -32,6 +32,9 @@
 	float frequency;
 	long totalFrames;
 
+	int metadataUpdateInterval;
+	int metadataUpdateCount;
+
 	NSDictionary *metaDict;
 	NSDictionary *icyMetaDict;
 

Plugins/Vorbis/VorbisDecoder.m

@@ -109,6 +109,9 @@ long sourceTell(void *datasource) {
 
 	[self updateMetadata];
 
+	metadataUpdateInterval = frequency;
+	metadataUpdateCount = 0;
+
 	return YES;
 }
 
@@ -215,6 +218,9 @@ static void setDictionary(NSMutableDictionary *dict, NSString *tag, NSString *va
 		channels = vi->channels;
 		frequency = vi->rate;
 
+		metadataUpdateInterval = frequency;
+		metadataUpdateCount = 0;
+
 		[self willChangeValueForKey:@"properties"];
 		[self didChangeValueForKey:@"properties"];
 
@@ -254,7 +260,11 @@ static void setDictionary(NSMutableDictionary *dict, NSString *tag, NSString *va
 
 	} while(total != frames && numread != 0);
 
-	[self updateIcyMetadata];
+	metadataUpdateCount += total;
+	if(metadataUpdateCount >= metadataUpdateInterval) {
+		metadataUpdateCount -= metadataUpdateInterval;
+		[self updateIcyMetadata];
+	}
 
 	[chunk assignSamples:buffer frameCount:total];