replay_gain: added mode "auto"

NEWS

@@ -77,6 +77,7 @@ ver 0.16 (20??/??/??)
   - reimplemented as a filter plugin
   - fall back to track gain if album gain is unavailable
   - optionally use hardware mixer to apply replay gain
+  - added mode "auto"
 * log unused/unknown block parameters
 * removed the deprecated "error_file" option
 * save state when stopped

doc/mpd.conf.5

@@ -170,12 +170,14 @@ only choice) if MPD was compiled without libsamplerate.
 For an up-to-date list of available converters, please see the libsamplerate
 documentation (available online at <\fBhttp://www.mega-nerd.com/SRC/\fP>).
 .TP
-.B replaygain <off or album or track>
+.B replaygain <off or album or track or auto>
 If specified, mpd will adjust the volume of songs played using ReplayGain tags
 (see <\fBhttp://www.replaygain.org/\fP>).  Setting this to "album" will adjust
 volume using the album's ReplayGain tags, while setting it to "track" will
-adjust it using the track ReplayGain tags.  Currently only FLAC, Ogg Vorbis,
-Musepack, and MP3 (through ID3v2 ReplayGain tags, not APEv2) are supported.
+adjust it using the track ReplayGain tags.  "auto" uses the track ReplayGain
+tags if random play is activated otherwise the album ReplayGain tags. Currently
+only FLAC, Ogg Vorbis, Musepack, and MP3 (through ID3v2 ReplayGain tags, not
+APEv2) are supported.
 .TP
 .B replaygain_preamp <-15 to 15>
 This is the gain (in dB) applied to songs with ReplayGain tags.

src/filter/replay_gain_filter_plugin.c

@@ -28,6 +28,7 @@
 #include "replay_gain_info.h"
 #include "replay_gain_config.h"
 #include "mixer_control.h"
+#include "playlist.h"
 
 #include <assert.h>
 #include <string.h>
@@ -114,7 +115,11 @@ replay_gain_filter_init(G_GNUC_UNUSED const struct config_param *param,
 	filter_init(&filter->filter, &replay_gain_filter_plugin);
 	filter->mixer = NULL;
 
+	if (replay_gain_mode == REPLAY_GAIN_AUTO) {
+	    filter->mode = g_playlist.queue.random ? REPLAY_GAIN_TRACK : REPLAY_GAIN_ALBUM;
+	} else {
 	    filter->mode = replay_gain_mode;
+	}
 	replay_gain_info_init(&filter->info);
 	filter->volume = PCM_VOLUME_1;
 
@@ -161,10 +166,18 @@ replay_gain_filter_filter(struct filter *_filter,
 		(struct replay_gain_filter *)_filter;
 	bool success;
 	void *dest;
+	enum replay_gain_mode rg_mode;
 
 	/* check if the mode has been changed since the last call */
-	if (filter->mode != replay_gain_mode) {
-		filter->mode = replay_gain_mode;
+	if (replay_gain_mode == REPLAY_GAIN_AUTO) {
+	    rg_mode = g_playlist.queue.random ? REPLAY_GAIN_TRACK : REPLAY_GAIN_ALBUM;
+	} else {
+	    rg_mode = replay_gain_mode;
+	}
+
+	if (filter->mode != rg_mode) {
+		g_debug("replay gain mode has changed %d->%d\n", filter->mode, rg_mode);
+		filter->mode = rg_mode;
 		replay_gain_filter_update(filter);
 	}
 

src/replay_gain_config.c

@@ -43,6 +43,9 @@ const char *
 replay_gain_get_mode_string(void)
 {
 	switch (replay_gain_mode) {
+	case REPLAY_GAIN_AUTO:
+		return "auto";
+
 	case REPLAY_GAIN_OFF:
 		return "off";
 
@@ -69,6 +72,8 @@ replay_gain_set_mode_string(const char *p)
 		replay_gain_mode = REPLAY_GAIN_TRACK;
 	else if (strcmp(p, "album") == 0)
 		replay_gain_mode = REPLAY_GAIN_ALBUM;
+	else if (strcmp(p, "auto") == 0)
+		replay_gain_mode = REPLAY_GAIN_AUTO;
 	else
 		return false;
 

src/replay_gain_info.h

@@ -26,7 +26,8 @@
 #include <math.h>
 
 enum replay_gain_mode {
-	REPLAY_GAIN_OFF = -1,
+	REPLAY_GAIN_AUTO = -2,
+	REPLAY_GAIN_OFF,
 	REPLAY_GAIN_ALBUM,
 	REPLAY_GAIN_TRACK,
 };

test/run_filter.c

@@ -25,6 +25,7 @@
 #include "pcm_volume.h"
 #include "idle.h"
 #include "mixer_control.h"
+#include "playlist.h"
 
 #include <glib.h>
 
@@ -33,6 +34,8 @@
 #include <errno.h>
 #include <unistd.h>
 
+struct playlist g_playlist;
+
 void
 idle_add(G_GNUC_UNUSED unsigned flags)
 {

test/run_output.c

@@ -27,6 +27,7 @@
 #include "pcm_convert.h"
 #include "event_pipe.h"
 #include "idle.h"
+#include "playlist.h"
 
 #include <glib.h>
 
@@ -34,6 +35,8 @@
 #include <string.h>
 #include <unistd.h>
 
+struct playlist g_playlist;
+
 void
 idle_add(G_GNUC_UNUSED unsigned flags)
 {