diff --git a/src/output_control.c b/src/output_control.c
index db3ab5622..323ed1276 100644
--- a/src/output_control.c
+++ b/src/output_control.c
@@ -56,22 +56,22 @@ audio_output_open(struct audio_output *audioOutput,
 	audioOutput->reopen_after = 0;
 
 	if (audioOutput->open &&
-	    audio_format_equals(audioFormat, &audioOutput->inAudioFormat)) {
+	    audio_format_equals(audioFormat, &audioOutput->in_audio_format)) {
 		return true;
 	}
 
-	audioOutput->inAudioFormat = *audioFormat;
+	audioOutput->in_audio_format = *audioFormat;
 
-	if (audio_format_defined(&audioOutput->reqAudioFormat)) {
-		/* copy reqAudioFormat to outAudioFormat only if the
+	if (audio_format_defined(&audioOutput->config_audio_format)) {
+		/* copy config_audio_format to out_audio_format only if the
 		   device is not yet open; if it is already open,
-		   plugin->open() may have modified outAudioFormat,
+		   plugin->open() may have modified out_audio_format,
 		   and the value is already ok */
 		if (!audioOutput->open)
-			audioOutput->outAudioFormat =
-				audioOutput->reqAudioFormat;
+			audioOutput->out_audio_format =
+				audioOutput->config_audio_format;
 	} else {
-		audioOutput->outAudioFormat = audioOutput->inAudioFormat;
+		audioOutput->out_audio_format = audioOutput->in_audio_format;
 		if (audioOutput->open)
 			audio_output_close(audioOutput);
 	}
diff --git a/src/output_init.c b/src/output_init.c
index 6d974bdb8..a3231f4d2 100644
--- a/src/output_init.c
+++ b/src/output_init.c
@@ -91,20 +91,21 @@ audio_output_init(struct audio_output *ao, const struct config_param *param)
 	ao->open = false;
 	ao->reopen_after = 0;
 
-	pcm_convert_init(&ao->convState);
+	pcm_convert_init(&ao->convert_state);
 
 	if (format) {
-		if (0 != parseAudioConfig(&ao->reqAudioFormat, format)) {
+		if (0 != parseAudioConfig(&ao->config_audio_format, format)) {
 			g_error("error parsing format at line %i\n", bp->line);
 		}
 	} else
-		audio_format_clear(&ao->reqAudioFormat);
+		audio_format_clear(&ao->config_audio_format);
 
 	ao->thread = NULL;
 	notify_init(&ao->notify);
 	ao->command = AO_COMMAND_NONE;
 
-	ao->data = plugin->init(ao, format ? &ao->reqAudioFormat : NULL, param);
+	ao->data = plugin->init(ao, format ? &ao->config_audio_format : NULL,
+				param);
 	if (ao->data == NULL)
 		return 0;
 
diff --git a/src/output_internal.h b/src/output_internal.h
index e53fc6a61..d2b6e41b2 100644
--- a/src/output_internal.h
+++ b/src/output_internal.h
@@ -63,23 +63,23 @@ struct audio_output {
 	 * The audio_format in which audio data is received from the
 	 * player thread (which in turn receives it from the decoder).
 	 */
-	struct audio_format inAudioFormat;
+	struct audio_format in_audio_format;
 
 	/**
 	 * The audio_format which is really sent to the device.  This
-	 * is basically reqAudioFormat (if configured) or
-	 * inAudioFormat, but may have been modified by
+	 * is basically config_audio_format (if configured) or
+	 * in_audio_format, but may have been modified by
 	 * plugin->open().
 	 */
-	struct audio_format outAudioFormat;
+	struct audio_format out_audio_format;
 
 	/**
 	 * The audio_format which was configured.  Only set if
 	 * convertAudioFormat is true.
 	 */
-	struct audio_format reqAudioFormat;
+	struct audio_format config_audio_format;
 
-	struct pcm_convert_state convState;
+	struct pcm_convert_state convert_state;
 
 	/**
 	 * The thread handle, or NULL if the output thread isn't
diff --git a/src/output_thread.c b/src/output_thread.c
index 883dddcaf..ef636180f 100644
--- a/src/output_thread.c
+++ b/src/output_thread.c
@@ -46,10 +46,10 @@ static void ao_play(struct audio_output *ao)
 
 	assert(size > 0);
 
-	if (!audio_format_equals(&ao->inAudioFormat, &ao->outAudioFormat)) {
-		data = pcm_convert(&ao->convState,
-				   &ao->inAudioFormat, data, size,
-				   &ao->outAudioFormat, &size);
+	if (!audio_format_equals(&ao->in_audio_format, &ao->out_audio_format)) {
+		data = pcm_convert(&ao->convert_state,
+				   &ao->in_audio_format, data, size,
+				   &ao->out_audio_format, &size);
 
 		/* under certain circumstances, pcm_convert() may
 		   return an empty buffer - this condition should be
@@ -63,7 +63,7 @@ static void ao_play(struct audio_output *ao)
 	if (!ret) {
 		ao->plugin->cancel(ao->data);
 		ao->plugin->close(ao->data);
-		pcm_convert_deinit(&ao->convState);
+		pcm_convert_deinit(&ao->convert_state);
 		ao->open = false;
 	}
 
@@ -84,7 +84,7 @@ static void ao_pause(struct audio_output *ao)
 			ret = ao->plugin->pause(ao->data);
 			if (!ret) {
 				ao->plugin->close(ao->data);
-				pcm_convert_deinit(&ao->convState);
+				pcm_convert_deinit(&ao->convert_state);
 				ao->open = false;
 			}
 		} while (ao->command == AO_COMMAND_NONE);
@@ -109,9 +109,9 @@ static gpointer audio_output_task(gpointer arg)
 		case AO_COMMAND_OPEN:
 			assert(!ao->open);
 
-			pcm_convert_init(&ao->convState);
+			pcm_convert_init(&ao->convert_state);
 			ret = ao->plugin->open(ao->data,
-					       &ao->outAudioFormat);
+					       &ao->out_audio_format);
 
 			assert(!ao->open);
 			if (ret == true)