/* must be called with the lock */
static gboolean
do_start (GstBufferPool * pool)
{
GstBufferPoolPrivate *priv = pool->priv;
if (!priv->started) {
GstBufferPoolClass *pclass;
pclass = GST_BUFFER_POOL_GET_CLASS (pool);
GST_LOG_OBJECT (pool, "starting");
/* start the pool, subclasses should allocate buffers and put them
* in the queue */
if (G_LIKELY (pclass->start)) {
if (!pclass->start (pool))
return FALSE;
}
priv->started = TRUE;
}
return TRUE;
}
static gboolean
gst_v4l2_buffer_pool_start (GstBufferPool * bpool)
{
GstV4l2BufferPool *pool = GST_V4L2_BUFFER_POOL (bpool);
GstBufferPoolClass *pclass = GST_BUFFER_POOL_CLASS (parent_class);
GstV4l2Object *obj = pool->obj;
GstStructure *config;
GstCaps *caps;
guint size, min_buffers, max_buffers;
guint max_latency, min_latency, copy_threshold = 0;
gboolean can_allocate = FALSE;
GST_DEBUG_OBJECT (pool, "activating pool");
config = gst_buffer_pool_get_config (bpool);
if (!gst_buffer_pool_config_get_params (config, &caps, &size, &min_buffers,
&max_buffers))
goto wrong_config;
min_latency = MAX (GST_V4L2_MIN_BUFFERS, obj->min_buffers);
switch (obj->mode) {
case GST_V4L2_IO_RW:
can_allocate = TRUE;
break;
case GST_V4L2_IO_DMABUF:
case GST_V4L2_IO_MMAP:
{
guint count;
can_allocate = GST_V4L2_ALLOCATOR_CAN_ALLOCATE (pool->vallocator, MMAP);
/* first, lets request buffers, and see how many we can get: */
GST_DEBUG_OBJECT (pool, "requesting %d MMAP buffers", min_buffers);
count = gst_v4l2_allocator_start (pool->vallocator, min_buffers,
V4L2_MEMORY_MMAP);
if (count < GST_V4L2_MIN_BUFFERS) {
min_buffers = count;
goto no_buffers;
}
/* V4L2 buffer pool are often very limited in the amount of buffers it
* can offer. The copy_threshold will workaround this limitation by
* falling back to copy if the pipeline needed more buffers. This also
* prevent having to do REQBUFS(N)/REQBUFS(0) everytime configure is
* called. */
if (count != min_buffers) {
GST_WARNING_OBJECT (pool, "using %u buffers instead of %u",
count, min_buffers);
min_buffers = count;
copy_threshold = min_latency;
/* The initial minimum could be provide either by GstBufferPool or
* driver needs. */
min_buffers = count;
}
break;
}
case GST_V4L2_IO_USERPTR:
{
guint count;
can_allocate =
GST_V4L2_ALLOCATOR_CAN_ALLOCATE (pool->vallocator, USERPTR);
GST_DEBUG_OBJECT (pool, "requesting %d USERPTR buffers", min_buffers);
count = gst_v4l2_allocator_start (pool->vallocator, min_buffers,
V4L2_MEMORY_USERPTR);
/* There is no rational to not get what we asked */
if (count < min_buffers) {
min_buffers = count;
goto no_buffers;
}
min_buffers = count;
break;
}
case GST_V4L2_IO_DMABUF_IMPORT:
{
guint count;
can_allocate = GST_V4L2_ALLOCATOR_CAN_ALLOCATE (pool->vallocator, DMABUF);
GST_DEBUG_OBJECT (pool, "requesting %d DMABUF buffers", min_buffers);
count = gst_v4l2_allocator_start (pool->vallocator, min_buffers,
V4L2_MEMORY_DMABUF);
/* There is no rational to not get what we asked */
if (count < min_buffers) {
min_buffers = count;
goto no_buffers;
}
min_buffers = count;
break;
}
default:
min_buffers = 0;
copy_threshold = 0;
g_assert_not_reached ();
break;
}
if (can_allocate)
max_latency = max_buffers;
else
max_latency = min_buffers;
pool->size = size;
pool->copy_threshold = copy_threshold;
pool->max_latency = max_latency;
pool->min_latency = min_latency;
pool->num_queued = 0;
if (max_buffers < min_buffers)
max_buffers = min_buffers;
gst_buffer_pool_config_set_params (config, caps, size, min_buffers,
max_buffers);
pclass->set_config (bpool, config);
gst_structure_free (config);
if (pool->other_pool)
if (!gst_buffer_pool_set_active (pool->other_pool, TRUE))
goto other_pool_failed;
/* now, allocate the buffers: */
if (!pclass->start (bpool))
goto start_failed;
if (!V4L2_TYPE_IS_OUTPUT (obj->type))
pool->group_released_handler =
g_signal_connect_swapped (pool->vallocator, "group-released",
G_CALLBACK (gst_v4l2_buffer_pool_group_released), pool);
return TRUE;
/* ERRORS */
wrong_config:
{
GST_ERROR_OBJECT (pool, "invalid config %" GST_PTR_FORMAT, config);
gst_structure_free (config);
return FALSE;
}
no_buffers:
{
GST_ERROR_OBJECT (pool,
"we received %d buffer from device '%s', we want at least %d",
min_buffers, obj->videodev, GST_V4L2_MIN_BUFFERS);
gst_structure_free (config);
return FALSE;
}
start_failed:
{
GST_ERROR_OBJECT (pool, "failed to start streaming");
return FALSE;
}
other_pool_failed:
{
GST_ERROR_OBJECT (pool, "failed to active the other pool %"
GST_PTR_FORMAT, pool->other_pool);
return FALSE;
}
}
