to_xmp_buffer
Description:
Formats a taglist as a xmp packet using only the selected schemas.
An empty list (null) means that all schemas should be used
Parameters:
| list | 
           tags  | 
      
| read_only | 
           does the container forbid inplace editing  | 
      
| schemas | 
           null terminated array of schemas to be used on serialization  | 
      
Returns:
| 
           new buffer or null, unref the buffer when done  | 
      
Namespace: Gst.Tag.List
  
  Package: gstreamer-tag-1.0