Query the original opaque parameter of an allocated buffer in the pool.
@param ref a buffer reference to a buffer returned by av_buffer_pool_get.
@return the opaque parameter set by the buffer allocator function of the
buffer pool.
@note the opaque parameter of ref is used by the buffer pool implementation,
therefore you have to use this function to access the original opaque
parameter of an allocated buffer.
Query the original opaque parameter of an allocated buffer in the pool.
@param ref a buffer reference to a buffer returned by av_buffer_pool_get. @return the opaque parameter set by the buffer allocator function of the buffer pool.
@note the opaque parameter of ref is used by the buffer pool implementation, therefore you have to use this function to access the original opaque parameter of an allocated buffer.