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v4l2: dequeue buffers when all are queued

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Prefer to always use the default bufferpool queue for the _acquire function
because it properly supports unblocking when setting inactive etc. As a result,
we need to dequeue buffers and put them back in the bufferpool queue when we
have queued all buffers in the sink.
Rename some variables to more meaningfull names to avoid a problem with
freeing the wrong amount of buffers.
This commit is contained in:
Wim Taymans 2011-07-25 14:47:05 +01:00
parent 7ca40d7a53
commit 0a88ac4c92
2 changed files with 30 additions and 35 deletions
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59
sys/v4l2/gstv4l2bufferpool.c
View file

@ -141,7 +141,7 @@ gst_v4l2_buffer_pool_alloc_buffer (GstBufferPool * bpool, GstBuffer ** buffer,
newbuf = gst_buffer_new ();
meta = GST_META_V4L2_ADD (newbuf);
index = pool->index;
index = pool->num_allocated;
GST_LOG_OBJECT (pool, "creating buffer %u, %p", index, newbuf, pool);
@ -195,7 +195,7 @@ gst_v4l2_buffer_pool_alloc_buffer (GstBufferPool * bpool, GstBuffer ** buffer,
break;
}
pool->index++;
pool->num_allocated++;
*buffer = newbuf;
@ -342,7 +342,7 @@ gst_v4l2_buffer_pool_start (GstBufferPool * bpool)
pool->obj = obj;
pool->max_buffers = max_buffers;
pool->buffers = g_new0 (GstBuffer *, max_buffers);
pool->index = 0;
pool->num_allocated = 0;
/* now, allocate the buffers: */
for (n = 0; n < min_buffers; n++) {
@ -421,7 +421,7 @@ gst_v4l2_buffer_pool_stop (GstBufferPool * bpool)
ret = GST_BUFFER_POOL_CLASS (parent_class)->stop (bpool);
/* then free the remaining buffers */
for (n = 0; n < pool->num_buffers; n++) {
for (n = 0; n < pool->num_allocated; n++) {
if (pool->buffers[n])
gst_v4l2_buffer_pool_free_buffer (bpool, pool->buffers[n]);
}
@ -655,7 +655,8 @@ gst_v4l2_buffer_pool_acquire_buffer (GstBufferPool * bpool, GstBuffer ** buffer,
case GST_V4L2_IO_MMAP:
/* just dequeue a buffer, we basically use the queue of v4l2 as the
* storage for our buffers. */
* storage for our buffers. This function does poll first so we can
* interrupt it fine. */
ret = gst_v4l2_buffer_pool_dqbuf (pool, buffer);
break;
@ -676,24 +677,10 @@ gst_v4l2_buffer_pool_acquire_buffer (GstBufferPool * bpool, GstBuffer ** buffer,
break;
case GST_V4L2_IO_MMAP:
{
GstBufferPoolParams tparams = { 0, };
if (params)
tparams = *params;
tparams.flags |= GST_BUFFER_POOL_FLAG_DONTWAIT;
/* first try to get a free unqueued buffer */
/* get a free unqueued buffer */
ret = GST_BUFFER_POOL_CLASS (parent_class)->acquire_buffer (bpool,
buffer, &tparams);
if (ret == GST_FLOW_UNEXPECTED) {
GST_DEBUG_OBJECT (pool, "pool empty, try to dequeue a buffer");
/* all buffers are queued, try to dequeue one */
ret = gst_v4l2_buffer_pool_dqbuf (pool, buffer);
}
buffer, params);
break;
}
case GST_V4L2_IO_USERPTR:
default:
@ -758,6 +745,9 @@ gst_v4l2_buffer_pool_release_buffer (GstBufferPool * bpool, GstBuffer * buffer)
/* playback, put the buffer back in the queue to refill later. */
GST_BUFFER_POOL_CLASS (parent_class)->release_buffer (bpool, buffer);
} else {
/* the buffer is queued in the device but maybe not played yet. We just
* leave it there and not make it available for future calls to acquire
* for now. The buffer will be dequeued and reused later. */
GST_LOG_OBJECT (pool, "buffer is queued");
}
break;
@ -810,15 +800,10 @@ gst_v4l2_buffer_pool_class_init (GstV4l2BufferPoolClass * klass)
/**
* gst_v4l2_buffer_pool_new:
* @obj: the v4l2 object owning the pool
* @num_buffers: the requested number of buffers in the pool
* @requeuebuf: if %TRUE, and if the pool is still in the running state, a
* buffer with no remaining references is immediately passed back to v4l2
* (VIDIOC_QBUF), otherwise it is returned to the pool of available buffers
* (which can be accessed via gst_v4l2_buffer_pool_get().
*
* Construct a new buffer pool.
*
* Returns: the new pool, use gst_v4l2_buffer_pool_destroy() to free resources
* Returns: the new pool, use gst_object_unref() to free resources
*/
GstBufferPool *
gst_v4l2_buffer_pool_new (GstV4l2Object * obj)
@ -976,13 +961,11 @@ gst_v4l2_buffer_pool_process (GstBufferPool * bpool, GstBuffer * buf)
/* nothing, we can queue directly */
to_queue = buf;
} else {
/* 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_UNEXPECTED) {
GST_DEBUG_OBJECT (pool, "pool empty, try to dequeue a buffer");
/* all buffers are queued, try to dequeue one */
ret = gst_v4l2_buffer_pool_dqbuf (pool, &to_queue);
}
if (ret != GST_FLOW_OK)
goto done;
@ -999,6 +982,18 @@ gst_v4l2_buffer_pool_process (GstBufferPool * bpool, GstBuffer * buf)
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;
}

6
sys/v4l2/gstv4l2bufferpool.h
View file

@ -57,9 +57,9 @@ struct _GstV4l2BufferPool
guint prefix;
guint align;
guint num_buffers; /* number of buffers allocated by the driver */
guint num_queued; /* number of buffers queued in the driver */
gint index;
guint num_buffers;
guint num_allocated; /* number of buffers allocated by the driver */
guint num_queued; /* number of buffers queued in the driver */
gboolean streaming;