Get the total size of @length memory blocks stating from @idx in @buffer.
When not %NULL, @offset will contain the offset of the data in the
memory block in @buffer at @idx and @maxsize will contain the sum of the size
and @offset and the amount of extra padding on the memory block at @idx +
@length -1.
@offset and @maxsize can be used to resize the buffer memory blocks with
gst_buffer_resize_range().
Get the total size of @length memory blocks stating from @idx in @buffer.
When not %NULL, @offset will contain the offset of the data in the memory block in @buffer at @idx and @maxsize will contain the sum of the size and @offset and the amount of extra padding on the memory block at @idx + @length -1. @offset and @maxsize can be used to resize the buffer memory blocks with gst_buffer_resize_range().