replay_gain: reimplement as a filter plugin

Apply the replay gain in the output thread.  This means a new setting
will be active instantly, without going through the whole music pipe.
And we might have different replay gain settings for each audio output
device.

4 files changed, 33 insertions, 18 deletions

diff --git a/src/decoder_api.c b/src/decoder_api.c
index 7dfe84062..285e21a6b 100644
--- a/src/decoder_api.c
+++ b/src/decoder_api.c
@@ -27,8 +27,6 @@
 #include "buffer.h"
 #include "pipe.h"
 #include "chunk.h"
-#include "replay_gain_state.h"
-#include "replay_gain_config.h"
 
 #include <glib.h>
 
@@ -343,13 +341,6 @@ decoder_data(struct decoder *decoder,
 
 		memcpy(dest, data, nbytes);
 
-		/* apply replay gain or normalization */
-
-		replay_gain_state_set_mode(decoder->replay_gain,
-					   replay_gain_mode);
-		replay_gain_state_apply(decoder->replay_gain,
-					dest, nbytes, &dc->out_audio_format);
-
 		/* expand the music pipe chunk */
 
 		full = music_chunk_expand(chunk, &dc->out_audio_format, nbytes);
@@ -418,5 +409,21 @@ decoder_replay_gain(struct decoder *decoder,
 {
 	assert(decoder != NULL);
 
-	replay_gain_state_set_info(decoder->replay_gain, replay_gain_info);
+	if (replay_gain_info != NULL) {
+		static unsigned serial;
+		if (++serial == 0)
+			serial = 1;
+
+		decoder->replay_gain_info = *replay_gain_info;
+		decoder->replay_gain_serial = serial;
+
+		if (decoder->chunk != NULL) {
+			/* flush the current chunk because the new
+			   replay gain values affect the following
+			   samples */
+			decoder_flush_chunk(decoder);
+			player_lock_signal();
+		}
+	} else
+		decoder->replay_gain_serial = 0;
 }
diff --git a/src/decoder_internal.c b/src/decoder_internal.c
index 7829b4d76..990d728e9 100644
--- a/src/decoder_internal.c
+++ b/src/decoder_internal.c
@@ -86,8 +86,15 @@ decoder_get_chunk(struct decoder *decoder, struct input_stream *is)
 
 	do {
 		decoder->chunk = music_buffer_allocate(dc->buffer);
-		if (decoder->chunk != NULL)
+		if (decoder->chunk != NULL) {
+			decoder->chunk->replay_gain_serial =
+				decoder->replay_gain_serial;
+			if (decoder->replay_gain_serial != 0)
+				decoder->chunk->replay_gain_info =
+					decoder->replay_gain_info;
+
 			return decoder->chunk;
+		}
 
 		decoder_lock(dc);
 		cmd = need_chunks(dc, is, true);
diff --git a/src/decoder_internal.h b/src/decoder_internal.h
index 159b40b92..9e7e2037a 100644
--- a/src/decoder_internal.h
+++ b/src/decoder_internal.h
@@ -22,6 +22,7 @@
 
 #include "decoder_command.h"
 #include "pcm_convert.h"
+#include "replay_gain_info.h"
 
 struct input_stream;
 
@@ -53,7 +54,13 @@ struct decoder {
 	/** the chunk currently being written to */
 	struct music_chunk *chunk;
 
-	struct replay_gain_state *replay_gain;
+	struct replay_gain_info replay_gain_info;
+
+	/**
+	 * A positive serial number for checking if replay gain info
+	 * has changed since the last check.
+	 */
+	unsigned replay_gain_serial;
 };
 
 /**
diff --git a/src/decoder_thread.c b/src/decoder_thread.c
index 42a537ffe..99fa2c7e2 100644
--- a/src/decoder_thread.c
+++ b/src/decoder_thread.c
@@ -31,8 +31,6 @@
 #include "mapper.h"
 #include "path.h"
 #include "uri.h"
-#include "replay_gain_state.h"
-#include "replay_gain_config.h"
 
 #include <glib.h>
 
@@ -351,8 +349,6 @@ decoder_run_song(struct decoder_control *dc,
 {
 	struct decoder decoder = {
 		.dc = dc,
-		.replay_gain = replay_gain_state_new(replay_gain_preamp,
-						     replay_gain_missing_preamp),
 	};
 	int ret;
 
@@ -380,8 +376,6 @@ decoder_run_song(struct decoder_control *dc,
 	pcm_convert_deinit(&decoder.conv_state);
 
 	/* flush the last chunk */
-	if (decoder.replay_gain != NULL)
-		replay_gain_state_free(decoder.replay_gain);
 
 	if (decoder.chunk != NULL)
 		decoder_flush_chunk(&decoder);