[gst-devel] Re: bufferpools

[David Schleef]

On Thu, Jan 08, 2004 at 04:10:00PM +0100, Julien MOUTTE wrote:
> 
> Hi David,
> 
> I'd like to implement bufferpools again in x[v]imagesink asap.. Could
> you please point me to a template/doc on how to do that ?
> 
> The best for me would be a simple testcase showing how to use the buffer
> free methods to replace bufferpools.


x[v]imagesink should call gst_pad_set_bufferalloc_function() on
their sink pads with a bufferalloc implementation.  This bufferalloc
function is to allocate buffers that _peers_ will send _to_ that pad.

A trivial version of a bufferalloc function, i.e., one that just
allocates normal buffers:

static GstBuffer *
gst_ximagesink_sink_bufferalloc (GstPad *pad, guint64 offset, guint
size)
{
  GstBuffer *buffer;

  buffer = gst_buffer_new_and_alloc (size);
  GST_DATA_FREE_FUNC (data) = gst_ximagesink_buffer_free;
  GST_BUFFER_POOL_PRIVATE (data) = ximagesink; /* whatever */

  return buffer;
}

static void
gst_ximagesink_buffer_free (GstData *data)
{
  g_free (GST_BUFFER_DATA (data));
}

The hard part is going through each element, and every time it
allocates a buffer using gst_buffer_new_and_alloc () that is then
sent to a sink pad, the call should be replaced with
gst_pad_alloc_buffer (sinkpad, offset, size).



dave...