/**
* gst_buffer_pool_acquire_buffer:
* @pool: a #GstBufferPool
* @buffer: (out): a location for a #GstBuffer
* @params: (transfer none) (allow-none) parameters.
*
* Acquire a buffer from @pool. @buffer should point to a memory location that
* can hold a pointer to the new buffer.
*
* @params can be NULL or contain optional parameters to influence the allocation.
*
* Returns: a #GstFlowReturn such as GST_FLOW_FLUSHING when the pool is
* inactive.
*/
GstFlowReturn
gst_buffer_pool_acquire_buffer (GstBufferPool * pool, GstBuffer ** buffer,
GstBufferPoolAcquireParams * params)
{
GstBufferPoolClass *pclass;
GstFlowReturn result;
g_return_val_if_fail (GST_IS_BUFFER_POOL (pool), GST_FLOW_ERROR);
g_return_val_if_fail (buffer != NULL, GST_FLOW_ERROR);
pclass = GST_BUFFER_POOL_GET_CLASS (pool);
/* assume we'll have one more outstanding buffer we need to do that so
* that concurrent set_active doesn't clear the buffers */
g_atomic_int_inc (&pool->priv->outstanding);
if (G_LIKELY (pclass->acquire_buffer))
result = pclass->acquire_buffer (pool, buffer, params);
else
result = GST_FLOW_NOT_SUPPORTED;
if (G_LIKELY (result == GST_FLOW_OK)) {
/* all buffers from the pool point to the pool and have the refcount of the
* pool incremented */
(*buffer)->pool = gst_object_ref (pool);
} else {
dec_outstanding (pool);
}
return result;
}
static GstFlowReturn
gst_v4l2_buffer_pool_acquire_buffer (GstBufferPool * bpool, GstBuffer ** buffer,
GstBufferPoolAcquireParams * params)
{
GstFlowReturn ret;
GstV4l2BufferPool *pool = GST_V4L2_BUFFER_POOL (bpool);
GstBufferPoolClass *pclass = GST_BUFFER_POOL_CLASS (parent_class);
GstV4l2Object *obj = pool->obj;
GST_DEBUG_OBJECT (pool, "acquire");
/* If this is being called to resurect a lost buffer */
if (params && params->flags & GST_V4L2_BUFFER_POOL_ACQUIRE_FLAG_RESURRECT) {
ret = pclass->acquire_buffer (bpool, buffer, params);
goto done;
}
switch (obj->type) {
case V4L2_BUF_TYPE_VIDEO_CAPTURE:
case V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE:
/* capture, This function should return a buffer with new captured data */
switch (obj->mode) {
case GST_V4L2_IO_RW:
{
/* take empty buffer from the pool */
ret = pclass->acquire_buffer (bpool, buffer, params);
break;
}
case GST_V4L2_IO_DMABUF:
case GST_V4L2_IO_MMAP:
{
/* just dequeue a buffer, we basically use the queue of v4l2 as the
* storage for our buffers. This function does poll first so we can
* interrupt it fine. */
ret = gst_v4l2_buffer_pool_dqbuf (pool, buffer);
if (G_UNLIKELY (ret != GST_FLOW_OK))
goto done;
break;
}
case GST_V4L2_IO_USERPTR:
case GST_V4L2_IO_DMABUF_IMPORT:
{
/* dequeue filled buffer */
ret = gst_v4l2_buffer_pool_dqbuf (pool, buffer);
break;
}
default:
ret = GST_FLOW_ERROR;
g_assert_not_reached ();
break;
}
break;
case V4L2_BUF_TYPE_VIDEO_OUTPUT:
case V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE:
/* playback, This function should return an empty buffer */
switch (obj->mode) {
case GST_V4L2_IO_RW:
/* get an empty buffer */
ret = pclass->acquire_buffer (bpool, buffer, params);
break;
case GST_V4L2_IO_MMAP:
case GST_V4L2_IO_DMABUF:
case GST_V4L2_IO_USERPTR:
case GST_V4L2_IO_DMABUF_IMPORT:
/* get a free unqueued buffer */
ret = pclass->acquire_buffer (bpool, buffer, params);
break;
default:
ret = GST_FLOW_ERROR;
g_assert_not_reached ();
break;
}
break;
default:
ret = GST_FLOW_ERROR;
g_assert_not_reached ();
break;
}
done:
return ret;
}
