res/ari/resource_bridges.c: Normalize channel_format ref handling for bridge media

Always take an explicit reference on the format used for bridge playback
and recording channels, regardless of where it was sourced, and release
it after prepare_bridge_media_channel. This aligns the code paths and
avoids mixing borrowed and owned references while preserving behavior.

Fixes: #1648

res/ari/resource_bridges.c

@@ -450,21 +450,18 @@ static void ari_bridges_play_new(const char **args_media,
 				"specified announcer_format is unknown on this system");
 			return;
 		}
-		/*
-		 * ast_format_cache_get() bumps the refcount but the other calls
-		 * to retrieve formats don't so we'll drop this reference.
-		 * It'll be bumped again in the prepare_bridge_media_channel() call below.
-		 */
-		ao2_ref(channel_format, -1);
 	} else {
 		ast_bridge_lock(bridge);
 		if (bridge->num_channels == 0) {
-			channel_format = ast_format_slin;
+			channel_format = ao2_bump(ast_format_slin);
 		} else if (bridge->num_channels == 1) {
 			struct ast_bridge_channel *bc = NULL;
 			bc = AST_LIST_FIRST(&bridge->channels);
 			if (bc) {
 				channel_format = ast_channel_rawwriteformat(bc->chan);
+				if (channel_format) {
+					channel_format = ao2_bump(channel_format);
+				}
 			}
 		} else {
 			struct ast_bridge_channel *bc = NULL;
@@ -473,17 +470,18 @@ static void ari_bridges_play_new(const char **args_media,
 				struct ast_format *fmt = ast_channel_rawwriteformat(bc->chan);
 				max_sample_rate = MAX(ast_format_get_sample_rate(fmt), max_sample_rate);
 			}
-			channel_format = ast_format_cache_get_slin_by_rate(max_sample_rate);
+			channel_format = ao2_bump(ast_format_cache_get_slin_by_rate(max_sample_rate));
 		}
 		ast_bridge_unlock(bridge);
 	}
 
 	if (!channel_format) {
-		channel_format = ast_format_slin;
+		channel_format = ao2_bump(ast_format_slin);
 	}
 
 	play_channel = prepare_bridge_media_channel("Announcer", channel_format);
 	ao2_cleanup(channel_format);
+
 	if (!play_channel) {
 		ast_ari_response_error(
 			response, 500, "Internal Error", "Could not create playback channel");
@@ -741,15 +739,8 @@ void ast_ari_bridges_record(struct ast_variable *headers,
 				"specified recorder_format is unknown on this system");
 			return;
 		}
-		/*
-		 * ast_format_cache_get() bumps the refcount but the other calls
-		 * to retrieve formats don't so we'll drop this reference.
-		 * It'll be bumped again in the prepare_bridge_media_channel() call below.
-		 */
-		ao2_ref(channel_format, -1);
-
 	} else {
-		channel_format = file_format;
+		channel_format = ao2_bump(file_format);
 	}
 
 	if (!(record_channel = prepare_bridge_media_channel("Recorder", channel_format))) {
@@ -758,6 +749,8 @@ void ast_ari_bridges_record(struct ast_variable *headers,
 		return;
 	}
 
+	ao2_cleanup(channel_format);
+
 	bridge_topic = ast_bridge_topic(bridge);
 	channel_topic = ast_channel_topic(record_channel);