static GstFlowReturn
gst_v4l2_buffer_pool_acquire_buffer (GstBufferPool * bpool, GstBuffer ** buffer,
GstBufferPoolAcquireParams * params)
{
GstFlowReturn ret;
GstV4l2BufferPool *pool = GST_V4L2_BUFFER_POOL (bpool);
GstV4l2Object *obj = pool->obj;
GST_DEBUG_OBJECT (pool, "acquire");
if (GST_BUFFER_POOL_IS_FLUSHING (bpool))
goto flushing;
switch (obj->type) {
case V4L2_BUF_TYPE_VIDEO_CAPTURE:
/* 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 = GST_BUFFER_POOL_CLASS (parent_class)->acquire_buffer (bpool,
buffer, params);
break;
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;
/* start copying buffers when we are running low on buffers */
if (pool->num_queued < pool->copy_threshold) {
GstBuffer *copy;
/* copy the memory */
copy = gst_buffer_copy (*buffer);
GST_LOG_OBJECT (pool, "copy buffer %p->%p", *buffer, copy);
/* and requeue so that we can continue capturing */
ret = gst_v4l2_buffer_pool_qbuf (pool, *buffer);
*buffer = copy;
}
break;
case GST_V4L2_IO_USERPTR:
default:
g_assert_not_reached ();
break;
}
break;
case V4L2_BUF_TYPE_VIDEO_OUTPUT:
/* playback, This function should return an empty buffer */
switch (obj->mode) {
case GST_V4L2_IO_RW:
/* get an empty buffer */
ret = GST_BUFFER_POOL_CLASS (parent_class)->acquire_buffer (bpool,
buffer, params);
break;
case GST_V4L2_IO_MMAP:
/* get a free unqueued buffer */
ret = GST_BUFFER_POOL_CLASS (parent_class)->acquire_buffer (bpool,
buffer, params);
break;
case GST_V4L2_IO_USERPTR:
default:
g_assert_not_reached ();
break;
}
break;
default:
g_assert_not_reached ();
break;
}
done:
return ret;
/* ERRORS */
flushing:
{
GST_DEBUG_OBJECT (pool, "We are flushing");
return GST_FLOW_FLUSHING;
}
}
/**
* gst_v4l2_buffer_pool_process:
* @bpool: a #GstBufferPool
* @buf: a #GstBuffer
*
* Process @buf in @bpool. For capture devices, this functions fills @buf with
* data from the device. For output devices, this functions send the contents of
* @buf to the device for playback.
*
* Returns: %GST_FLOW_OK on success.
*/
GstFlowReturn
gst_v4l2_buffer_pool_process (GstV4l2BufferPool * pool, GstBuffer * buf)
{
GstFlowReturn ret = GST_FLOW_OK;
GstBufferPool *bpool = GST_BUFFER_POOL_CAST (pool);
GstV4l2Object *obj = pool->obj;
GST_DEBUG_OBJECT (pool, "process buffer %p", buf);
switch (obj->type) {
case V4L2_BUF_TYPE_VIDEO_CAPTURE:
/* capture */
switch (obj->mode) {
case GST_V4L2_IO_RW:
/* capture into the buffer */
ret = gst_v4l2_do_read (pool, buf);
break;
case GST_V4L2_IO_MMAP:
{
GstBuffer *tmp;
if (buf->pool == bpool)
/* nothing, data was inside the buffer when we did _acquire() */
goto done;
/* buffer not from our pool, grab a frame and copy it into the target */
if ((ret = gst_v4l2_buffer_pool_dqbuf (pool, &tmp)) != GST_FLOW_OK)
goto done;
if (!gst_v4l2_object_copy (obj, buf, tmp))
goto copy_failed;
/* an queue the buffer again after the copy */
if ((ret = gst_v4l2_buffer_pool_qbuf (pool, tmp)) != GST_FLOW_OK)
goto done;
break;
}
case GST_V4L2_IO_USERPTR:
default:
g_assert_not_reached ();
break;
}
break;
case V4L2_BUF_TYPE_VIDEO_OUTPUT:
/* playback */
switch (obj->mode) {
case GST_V4L2_IO_RW:
/* FIXME, do write() */
GST_WARNING_OBJECT (pool, "implement write()");
break;
case GST_V4L2_IO_MMAP:
{
GstBuffer *to_queue;
if (buf->pool == bpool) {
/* nothing, we can queue directly */
to_queue = buf;
GST_LOG_OBJECT (pool, "processing buffer from our pool");
} else {
GST_LOG_OBJECT (pool, "alloc buffer from our pool");
if (!gst_buffer_pool_is_active (bpool)) {
GstStructure *config;
/* this pool was not activated, configure and activate */
GST_DEBUG_OBJECT (pool, "activating pool");
config = gst_buffer_pool_get_config (bpool);
gst_buffer_pool_config_add_option (config,
GST_BUFFER_POOL_OPTION_VIDEO_META);
gst_buffer_pool_set_config (bpool, config);
if (!gst_buffer_pool_set_active (bpool, TRUE))
goto activate_failed;
}
/* this can block if all buffers are outstanding which would be
* strange because we would expect the upstream element to have
* allocated them and returned to us.. */
ret = GST_BUFFER_POOL_CLASS (parent_class)->acquire_buffer (bpool,
&to_queue, NULL);
if (ret != GST_FLOW_OK)
goto acquire_failed;
/* copy into it and queue */
if (!gst_v4l2_object_copy (obj, to_queue, buf))
goto copy_failed;
}
if ((ret = gst_v4l2_buffer_pool_qbuf (pool, to_queue)) != GST_FLOW_OK)
goto done;
/* if we are not streaming yet (this is the first buffer, start
* streaming now */
if (!pool->streaming)
if (!start_streaming (pool))
goto start_failed;
if (pool->num_queued == pool->num_allocated) {
/* all buffers are queued, try to dequeue one and release it back
* into the pool so that _acquire can get to it again. */
ret = gst_v4l2_buffer_pool_dqbuf (pool, &to_queue);
if (ret != GST_FLOW_OK)
goto done;
/* release the rendered buffer back into the pool. This wakes up any
* thread waiting for a buffer in _acquire() */
gst_v4l2_buffer_pool_release_buffer (bpool, to_queue);
}
break;
}
case GST_V4L2_IO_USERPTR:
default:
g_assert_not_reached ();
break;
}
break;
default:
g_assert_not_reached ();
break;
}
done:
return ret;
/* ERRORS */
activate_failed:
{
GST_ERROR_OBJECT (obj->element, "failed to activate pool");
return GST_FLOW_ERROR;
}
acquire_failed:
{
GST_WARNING_OBJECT (obj->element, "failed to acquire a buffer: %s",
gst_flow_get_name (ret));
return ret;
}
copy_failed:
{
GST_ERROR_OBJECT (obj->element, "failed to copy data");
return GST_FLOW_ERROR;
}
start_failed:
{
GST_ERROR_OBJECT (obj->element, "failed to start streaming");
return GST_FLOW_ERROR;
}
}
/**
* gst_v4l2_buffer_pool_process:
* @bpool: a #GstBufferPool
* @buf: a #GstBuffer, maybe be replaced
*
* Process @buf in @bpool. For capture devices, this functions fills @buf with
* data from the device. For output devices, this functions send the contents of
* @buf to the device for playback.
*
* Returns: %GST_FLOW_OK on success.
*/
GstFlowReturn
gst_v4l2_buffer_pool_process (GstV4l2BufferPool * pool, GstBuffer ** buf)
{
GstFlowReturn ret = GST_FLOW_OK;
GstBufferPool *bpool = GST_BUFFER_POOL_CAST (pool);
GstV4l2Object *obj = pool->obj;
GST_DEBUG_OBJECT (pool, "process buffer %p", buf);
g_return_val_if_fail (gst_buffer_pool_is_active (bpool), GST_FLOW_ERROR);
if (GST_BUFFER_POOL_IS_FLUSHING (pool))
return GST_FLOW_FLUSHING;
switch (obj->type) {
case V4L2_BUF_TYPE_VIDEO_CAPTURE:
case V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE:
/* capture */
switch (obj->mode) {
case GST_V4L2_IO_RW:
/* capture into the buffer */
ret = gst_v4l2_do_read (pool, *buf);
break;
case GST_V4L2_IO_MMAP:
case GST_V4L2_IO_DMABUF:
{
GstBuffer *tmp;
if ((*buf)->pool == bpool) {
if (gst_buffer_get_size (*buf) == 0)
goto eos;
/* start copying buffers when we are running low on buffers */
if (g_atomic_int_get (&pool->num_queued) < pool->copy_threshold) {
GstBuffer *copy;
if (GST_V4L2_ALLOCATOR_CAN_ALLOCATE (pool->vallocator, MMAP)) {
if (gst_buffer_pool_acquire_buffer (bpool, ©,
NULL) == GST_FLOW_OK) {
gst_v4l2_buffer_pool_release_buffer (bpool, copy);
goto done;
}
}
/* copy the buffer */
copy = gst_buffer_copy_region (*buf,
GST_BUFFER_COPY_ALL | GST_BUFFER_COPY_DEEP, 0, -1);
GST_LOG_OBJECT (pool, "copy buffer %p->%p", *buf, copy);
/* and requeue so that we can continue capturing */
gst_buffer_unref (*buf);
*buf = copy;
}
/* nothing, data was inside the buffer when we did _acquire() */
goto done;
}
/* buffer not from our pool, grab a frame and copy it into the target */
if ((ret = gst_v4l2_buffer_pool_dqbuf (pool, &tmp)) != GST_FLOW_OK)
goto done;
/* An empty buffer on capture indicates the end of stream */
if (gst_buffer_get_size (tmp) == 0) {
gst_v4l2_buffer_pool_release_buffer (bpool, tmp);
goto eos;
}
ret = gst_v4l2_buffer_pool_copy_buffer (pool, *buf, tmp);
/* an queue the buffer again after the copy */
gst_v4l2_buffer_pool_release_buffer (bpool, tmp);
if (ret != GST_FLOW_OK)
goto copy_failed;
break;
}
case GST_V4L2_IO_USERPTR:
{
struct UserPtrData *data;
/* Replace our buffer with downstream allocated buffer */
data = gst_mini_object_steal_qdata (GST_MINI_OBJECT (*buf),
GST_V4L2_IMPORT_QUARK);
gst_buffer_replace (buf, data->buffer);
_unmap_userptr_frame (data);
break;
}
case GST_V4L2_IO_DMABUF_IMPORT:
{
GstBuffer *tmp;
/* Replace our buffer with downstream allocated buffer */
tmp = gst_mini_object_steal_qdata (GST_MINI_OBJECT (*buf),
GST_V4L2_IMPORT_QUARK);
gst_buffer_replace (buf, tmp);
gst_buffer_unref (tmp);
break;
}
default:
g_assert_not_reached ();
break;
}
break;
case V4L2_BUF_TYPE_VIDEO_OUTPUT:
case V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE:
/* playback */
switch (obj->mode) {
case GST_V4L2_IO_RW:
/* FIXME, do write() */
GST_WARNING_OBJECT (pool, "implement write()");
break;
case GST_V4L2_IO_USERPTR:
case GST_V4L2_IO_DMABUF_IMPORT:
case GST_V4L2_IO_DMABUF:
case GST_V4L2_IO_MMAP:
{
GstBuffer *to_queue = NULL;
GstV4l2MemoryGroup *group;
gint index;
if ((*buf)->pool != bpool)
goto copying;
if (!gst_v4l2_is_buffer_valid (*buf, &group))
goto copying;
index = group->buffer.index;
GST_LOG_OBJECT (pool, "processing buffer %i from our pool", index);
index = group->buffer.index;
if (pool->buffers[index] != NULL) {
GST_LOG_OBJECT (pool, "buffer %i already queued, copying", index);
goto copying;
}
/* we can queue directly */
to_queue = gst_buffer_ref (*buf);
copying:
if (to_queue == NULL) {
GstBufferPoolAcquireParams params = { 0 };
GST_LOG_OBJECT (pool, "alloc buffer from our pool");
/* this can return EOS if all buffers are outstanding which would
* be strange because we would expect the upstream element to have
* allocated them and returned to us.. */
params.flags = GST_BUFFER_POOL_ACQUIRE_FLAG_DONTWAIT;
ret = gst_buffer_pool_acquire_buffer (bpool, &to_queue, ¶ms);
if (ret != GST_FLOW_OK)
goto acquire_failed;
ret = gst_v4l2_buffer_pool_prepare_buffer (pool, to_queue, *buf);
if (ret != GST_FLOW_OK) {
gst_buffer_unref (to_queue);
goto prepare_failed;
}
}
if ((ret = gst_v4l2_buffer_pool_qbuf (pool, to_queue)) != GST_FLOW_OK)
goto queue_failed;
/* if we are not streaming yet (this is the first buffer, start
* streaming now */
if (!gst_v4l2_buffer_pool_streamon (pool)) {
/* don't check return value because qbuf would have failed */
gst_v4l2_is_buffer_valid (to_queue, &group);
/* qbuf has taken the ref of the to_queue buffer but we are no in
* streaming state, so the flush logic won't be performed.
* To avoid leaks, flush the allocator and restore the queued
* buffer as non-queued */
gst_v4l2_allocator_flush (pool->vallocator);
pool->buffers[group->buffer.index] = NULL;
gst_mini_object_set_qdata (GST_MINI_OBJECT (to_queue),
GST_V4L2_IMPORT_QUARK, NULL, NULL);
gst_buffer_unref (to_queue);
g_atomic_int_add (&pool->num_queued, -1);
goto start_failed;
}
if (g_atomic_int_get (&pool->num_queued) >= pool->min_latency) {
GstBuffer *out;
/* all buffers are queued, try to dequeue one and release it back
* into the pool so that _acquire can get to it again. */
ret = gst_v4l2_buffer_pool_dqbuf (pool, &out);
if (ret == GST_FLOW_OK)
/* release the rendered buffer back into the pool. This wakes up any
* thread waiting for a buffer in _acquire(). */
gst_buffer_unref (out);
}
break;
}
default:
g_assert_not_reached ();
break;
}
break;
default:
g_assert_not_reached ();
break;
}
done:
return ret;
/* ERRORS */
copy_failed:
{
GST_ERROR_OBJECT (pool, "failed to copy buffer");
return ret;
}
eos:
{
GST_DEBUG_OBJECT (pool, "end of stream reached");
return GST_FLOW_EOS;
}
acquire_failed:
{
if (ret == GST_FLOW_FLUSHING)
GST_DEBUG_OBJECT (pool, "flushing");
else
GST_WARNING_OBJECT (pool, "failed to acquire a buffer: %s",
gst_flow_get_name (ret));
return ret;
}
prepare_failed:
{
GST_ERROR_OBJECT (pool, "failed to prepare data");
return ret;
}
queue_failed:
{
GST_ERROR_OBJECT (pool, "failed to queue buffer");
return ret;
}
start_failed:
{
GST_ERROR_OBJECT (pool, "failed to start streaming");
return GST_FLOW_ERROR;
}
}
/******************************************************
* gst_v4l2src_grab_frame ():
* grab a frame for capturing
* return value: GST_FLOW_OK, GST_FLOW_WRONG_STATE or GST_FLOW_ERROR
******************************************************/
GstFlowReturn
gst_v4l2src_grab_frame (GstV4l2Src * v4l2src, GstBuffer ** buf)
{
#define NUM_TRIALS 50
GstV4l2Object *v4l2object;
GstV4l2BufferPool *pool;
gint32 trials = NUM_TRIALS;
GstBuffer *pool_buffer;
gboolean need_copy;
gint ret;
v4l2object = v4l2src->v4l2object;
pool = v4l2src->pool;
if (!pool)
goto no_buffer_pool;
GST_DEBUG_OBJECT (v4l2src, "grab frame");
for (;;) {
if (v4l2object->can_poll_device) {
ret = gst_poll_wait (v4l2object->poll, GST_CLOCK_TIME_NONE);
if (G_UNLIKELY (ret < 0)) {
if (errno == EBUSY)
goto stopped;
if (errno == ENXIO) {
GST_DEBUG_OBJECT (v4l2src,
"v4l2 device doesn't support polling. Disabling");
v4l2object->can_poll_device = FALSE;
} else {
if (errno != EAGAIN && errno != EINTR)
goto select_error;
}
}
}
pool_buffer = GST_BUFFER (gst_v4l2_buffer_pool_dqbuf (pool));
if (pool_buffer)
break;
GST_WARNING_OBJECT (pool->v4l2elem, "trials=%d", trials);
/* if the sync() got interrupted, we can retry */
switch (errno) {
case EINVAL:
case ENOMEM:
/* fatal */
return GST_FLOW_ERROR;
case EAGAIN:
case EIO:
case EINTR:
default:
/* try again, until too many trials */
break;
}
/* check nr. of attempts to capture */
if (--trials == -1) {
goto too_many_trials;
}
}
/* if we are handing out the last buffer in the pool, we need to make a
* copy and bring the buffer back in the pool. */
need_copy = v4l2src->always_copy
|| !gst_v4l2_buffer_pool_available_buffers (pool);
if (G_UNLIKELY (need_copy)) {
if (!v4l2src->always_copy) {
GST_CAT_LOG_OBJECT (GST_CAT_PERFORMANCE, v4l2src,
"running out of buffers, making a copy to reuse current one");
}
*buf = gst_buffer_copy (pool_buffer);
GST_BUFFER_FLAG_UNSET (*buf, GST_BUFFER_FLAG_READONLY);
/* this will requeue */
gst_buffer_unref (pool_buffer);
} else {
*buf = pool_buffer;
}
/* we set the buffer metadata in gst_v4l2src_create() */
return GST_FLOW_OK;
/* ERRORS */
no_buffer_pool:
{
GST_DEBUG ("no buffer pool");
return GST_FLOW_WRONG_STATE;
}
select_error:
{
GST_ELEMENT_ERROR (pool->v4l2elem, RESOURCE, READ, (NULL),
("select error %d: %s (%d)", ret, g_strerror (errno), errno));
return GST_FLOW_ERROR;
}
stopped:
{
GST_DEBUG ("stop called");
return GST_FLOW_WRONG_STATE;
}
too_many_trials:
{
GST_ELEMENT_ERROR (pool->v4l2elem, RESOURCE, FAILED,
(_("Failed trying to get video frames from device '%s'."),
v4l2object->videodev),
(_("Failed after %d tries. device %s. system error: %s"),
NUM_TRIALS, v4l2object->videodev, g_strerror (errno)));
return GST_FLOW_ERROR;
}
}
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;
}
