Adding on the fly volume normalization support. Code originally from mplayer,…

doc/mpd.conf.5

@@ -92,6 +92,9 @@ Musepack, and MP3 (through ID3v2 replaygain tags, not APEv2) are supported.
 .B replaygain_preamp <-15 to 15>
 This is the gain (in dB) applied to songs with replaygain tags.
 .TP
+.B volume_normalization <yes or no>
+If yes, mpd will normalize the volume of songs as they play.  Default is no.
+.TP
 .B audio_buffer_size <size in KiB>
 This specifies the size of the audio output buffer that mpd uses.  The default
 is 2048.

doc/mpdconf.example

@@ -126,7 +126,7 @@ pid_file 		"~/.mpd/mpd.pid"
 ##########################################################
 
 
-################# REPLAYGAIN #############################
+################# Normalization ##########################
 #
 # Use Replay Gain (album or track)
 #	http://www.replaygain.org
@@ -138,6 +138,13 @@ pid_file 		"~/.mpd/mpd.pid"
 #
 #replaygain_preamp	"0"
 #
+# Normalization increases the amplitude of the audio
+# waveform to the maximum level without introducing any 
+# distortion into the recording. This option will 
+# normalize when replaygain is not on, utilizing the 
+# CPU for calculation.
+#
+#volume_normalization	"yes"
 ##########################################################
 
 

src/Makefile.am

@@ -49,6 +49,7 @@ mpd_headers = \
 	metadataChunk.h \
 	mpd_types.h \
 	myfprintf.h \
+	normalize.h \
 	outputBuffer.h \
 	path.h \
 	pcm_utils.h \
@@ -93,6 +94,7 @@ mpd_SOURCES = \
 	main.c \
 	metadataChunk.c \
 	myfprintf.c \
+	normalize.c \
 	outputBuffer.c \
 	path.c \
 	pcm_utils.c \

src/conf.c

@@ -171,6 +171,7 @@ void initConf(void)
 	registerConfigParam(CONF_REPLAYGAIN_PREAMP, 0, 0);
 	registerConfigParam(CONF_METADATA_TO_USE, 0, 0);
 	registerConfigParam(CONF_ID3V1_ENCODING, 0, 0);
+	registerConfigParam(CONF_VOLUME_NORMALIZATION, 0, 0);
 }
 
 static void addBlockParam(ConfigParam * param, char *name, char *value,

src/conf.h

@@ -58,6 +58,7 @@
 #define CONF_HTTP_PREBUFFER_SIZE	"http_prebuffer_size"
 #define CONF_METADATA_TO_USE		"metadata_to_use"
 #define CONF_ID3V1_ENCODING		"id3v1_encoding"
+#define CONF_VOLUME_NORMALIZATION	"volume_normalization"
 
 typedef struct _BlockParam {
 	char *name;

src/outputBuffer.c

@@ -22,6 +22,8 @@
 #include "playerData.h"
 #include "utils.h"
 #include "log.h"
+#include "normalize.h"
+#include "conf.h"
 
 #include <string.h>
 
@@ -76,6 +78,22 @@ int sendDataToOutputBuffer(OutputBuffer * cb, InputStream * inStream,
 	size_t datalen;
 	static char *convBuffer = NULL;
 	static long convBufferLen = 0;
+	static int normalEnable = -1;
+	ConfigParam *param;
+
+	if (normalEnable == -1) {
+		normalEnable = getBoolConfigParam(CONF_VOLUME_NORMALIZATION);
+		if (normalEnable == -1) {
+			/* not set */
+			normalEnable = 0;
+		} else if (normalEnable < 0) {
+			param = getConfigParam(CONF_VOLUME_NORMALIZATION);
+			WARNING("%s is not \"yes\" or \"no\" on line %i, "
+			        "disabling\n", CONF_VOLUME_NORMALIZATION,
+			        param->line);
+			normalEnable = 0;
+		}
+	}
 
 	if (cmpAudioFormat(&(cb->audioFormat), &(dc->audioFormat)) == 0) {
 		data = dataIn;
@@ -99,6 +117,8 @@ int sendDataToOutputBuffer(OutputBuffer * cb, InputStream * inStream,
 
 	if (replayGainInfo) {
 		doReplayGain(replayGainInfo, data, datalen, &cb->audioFormat);
+	} else if (normalEnable) {
+		normalizeData(data, datalen, &cb->audioFormat);
 	}
 
 	while (datalen) {