- , _frame_rate (node->number_child<int> ("FrameRate"))
- , _channels (node->number_child<int64_t> ("Channels"))
- , _mapping (node->node_child ("Mapping"), version)
+ , AudioStream (
+ node->number_child<int> ("FrameRate"),
+ node->optional_number_child<Frame>("Length").get_value_or (0),
+ AudioMapping (node->node_child ("Mapping"), version)
+ )