the offset of the new buffer in the stream
the size of the new buffer
the caps of the new buffer
a newly allocated buffer
a result code indicating success of the operation. Any result code other than GST_FLOW_OK is an error and buf should not be used. An error can occur if the pad is not connected or when the downstream peer elements cannot provide an acceptable buffer. MT safe.
In addition to the function gst_pad_alloc_buffer(), this function automatically calls gst_pad_set_caps() when the caps of the newly allocated buffer are different from the pad caps.