Avoid unnecessary downmixing when only determining audio duration.

For the purposes of estimating the duration, we don't need to incur
the overhead of downmixing 5.1 audios.

git-svn-id: svn://svn.daper.net/moc/trunk@3004 910807d9-36e0-0310-a014-e9ea483e2ba4

decoder_plugins/aac/aac.c

@@ -249,13 +249,14 @@ static int aac_count_time (struct aac_data *data)
 		return -1;
 
 	samples /= frames;
-	samples /= MIN(2, data->channels);
+	samples /= data->channels;
 	bytes /= frames;
 
 	return ((file_size / bytes) * samples) / data->sample_rate;
 }
 
-static void *aac_open_internal (struct io_stream *stream, const char *fname)
+static struct aac_data *aac_open_internal (struct io_stream *stream,
+                                           const char *fname, bool timing_only)
 {
 	struct aac_data *data;
 	NeAACDecConfigurationPtr neaac_cfg;
@@ -270,7 +271,7 @@ static void *aac_open_internal (struct io_stream *stream, const char *fname)
 	/* set decoder config */
 	neaac_cfg = NeAACDecGetCurrentConfiguration(data->decoder);
 	neaac_cfg->outputFormat = FAAD_FMT_16BIT;	/* force 16 bit audio */
-	neaac_cfg->downMatrix = 1;			/* 5.1 -> stereo */
+	neaac_cfg->downMatrix = !timing_only;		/* 5.1 -> stereo */
 	neaac_cfg->dontUpSampleImplicitSBR = 0;		/* upsample, please! */
 	NeAACDecSetConfiguration(data->decoder, neaac_cfg);
 
@@ -314,14 +315,16 @@ static void *aac_open_internal (struct io_stream *stream, const char *fname)
 		return data;
 	}
 
-	if (data->channels == 6) {
-		logit ("sample rate %dHz, channels %d (downmixed to stereo)",
-		        data->sample_rate, data->channels);
-		data->channels = 2;
+	if (!timing_only) {
+		if (data->channels == 6) {
+			logit ("sample rate %dHz, channels %d (downmixed to stereo)",
+			        data->sample_rate, data->channels);
+			data->channels = 2;
+		}
+		else
+			logit ("sample rate %dHz, channels %d",
+			        data->sample_rate, data->channels);
 	}
-	else
-		logit ("sample rate %dHz, channels %d", data->sample_rate,
-		                                        data->channels);
 
 	if (!data->sample_rate || !data->channels) {
 		decoder_error (&data->error, ERROR_FATAL, 0,
@@ -349,12 +352,11 @@ static void aac_close (void *prv_data)
 	free (data);
 }
 
-
 static void *aac_open (const char *file)
 {
 	struct aac_data *data;
 
-	data = aac_open_internal (NULL, file);
+	data = aac_open_internal (NULL, file, true);
 
 	if (data->ok) {
 		int duration = -1;
@@ -366,7 +368,8 @@ static void *aac_open (const char *file)
 		if (duration > 0 && file_size != -1)
 			avg_bitrate = file_size / duration * 8;
 		aac_close (data);
-		data = aac_open_internal (NULL, file);
+
+		data = aac_open_internal (NULL, file, false);
 		data->duration = duration;
 		data->avg_bitrate = avg_bitrate;
 	}
@@ -378,7 +381,7 @@ static void *aac_open_stream (struct io_stream *stream)
 {
 	assert (stream != NULL);
 
-	return aac_open_internal (stream, NULL);
+	return aac_open_internal (stream, NULL, false);
 }
 
 static char *get_tag (struct id3_tag *tag, const char *what)
@@ -433,7 +436,7 @@ static void aac_info (const char *file_name,
 	if (tags_sel & TAGS_TIME) {
 		struct aac_data *data;
 
-		data = aac_open_internal (NULL, file_name);
+		data = aac_open_internal (NULL, file_name, true);
 
 		if (data->ok)
 			info->time = aac_count_time (data);