gstreamer/sys/v4l2/gstv4l2bufferpool.c
Rob Clark 99e2ac121d v4l2sink: change where buffers get dequeued
It seems to cause strange occasional high latencies (almost 200ms) when dequeuing buffers from _buffer_alloc().  It is simpler and seems to work much better to dqbuf from the same thread that is queuing the next buffer.
2009-08-04 09:22:29 +02:00

600 lines
17 KiB
C

/* GStreamer
*
* Copyright (C) 2001-2002 Ronald Bultje <rbultje@ronald.bitfreak.net>
* 2006 Edgard Lima <edgard.lima@indt.org.br>
* 2009 Texas Instruments, Inc - http://www.ti.com/
*
* gstv4l2src.h: BT8x8/V4L2 source element
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include <sys/mman.h>
#include <string.h>
#include <unistd.h>
#include <gstv4l2bufferpool.h>
#include "gstv4l2src.h"
#include "gstv4l2sink.h"
#include "v4l2_calls.h"
#include "gst/gst-i18n-plugin.h"
GST_DEBUG_CATEGORY_EXTERN (v4l2_debug);
#define GST_CAT_DEFAULT v4l2_debug
/*
* GstV4l2Buffer:
*/
static GstBufferClass *v4l2buffer_parent_class = NULL;
static void
gst_v4l2_buffer_finalize (GstV4l2Buffer * buffer)
{
GstV4l2BufferPool *pool;
gboolean resuscitated = FALSE;
gint index;
pool = buffer->pool;
index = buffer->vbuffer.index;
GST_LOG_OBJECT (pool->v4l2elem, "finalizing buffer %p %d", buffer, index);
GST_V4L2_BUFFER_POOL_LOCK (pool);
if (pool->running) {
if (pool->requeuebuf) {
if (!gst_v4l2_buffer_pool_qbuf (pool, buffer)) {
GST_WARNING ("could not requeue buffer %p %d", buffer, index);
} else {
resuscitated = TRUE;
}
} else {
resuscitated = TRUE;
/* XXX double check this... I think it is ok to not synchronize this
* w.r.t. destruction of the pool, since the buffer is still live and
* the buffer holds a ref to the pool..
*/
g_async_queue_push (pool->avail_buffers, buffer);
}
} else {
GST_LOG_OBJECT (pool->v4l2elem, "the pool is shutting down");
}
if (resuscitated) {
/* FIXME: check that the caps didn't change */
GST_LOG_OBJECT (pool->v4l2elem, "reviving buffer %p, %d", buffer, index);
gst_buffer_ref (GST_BUFFER (buffer));
GST_BUFFER_SIZE (buffer) = 0;
pool->buffers[index] = buffer;
}
GST_V4L2_BUFFER_POOL_UNLOCK (pool);
if (!resuscitated) {
GST_LOG_OBJECT (pool->v4l2elem, "buffer %p not recovered, unmapping",
buffer);
gst_mini_object_unref (GST_MINI_OBJECT (pool));
v4l2_munmap ((void *) GST_BUFFER_DATA (buffer), buffer->vbuffer.length);
GST_MINI_OBJECT_CLASS (v4l2buffer_parent_class)->finalize (GST_MINI_OBJECT
(buffer));
}
}
static void
gst_v4l2_buffer_class_init (gpointer g_class, gpointer class_data)
{
GstMiniObjectClass *mini_object_class = GST_MINI_OBJECT_CLASS (g_class);
v4l2buffer_parent_class = g_type_class_peek_parent (g_class);
mini_object_class->finalize = (GstMiniObjectFinalizeFunction)
gst_v4l2_buffer_finalize;
}
GType
gst_v4l2_buffer_get_type (void)
{
static GType _gst_v4l2_buffer_type;
if (G_UNLIKELY (_gst_v4l2_buffer_type == 0)) {
static const GTypeInfo v4l2_buffer_info = {
sizeof (GstBufferClass),
NULL,
NULL,
gst_v4l2_buffer_class_init,
NULL,
NULL,
sizeof (GstV4l2Buffer),
0,
NULL,
NULL
};
_gst_v4l2_buffer_type = g_type_register_static (GST_TYPE_BUFFER,
"GstV4l2Buffer", &v4l2_buffer_info, 0);
}
return _gst_v4l2_buffer_type;
}
static GstV4l2Buffer *
gst_v4l2_buffer_new (GstV4l2BufferPool * pool, guint index, GstCaps * caps)
{
GstV4l2Buffer *ret;
guint8 *data;
ret = (GstV4l2Buffer *) gst_mini_object_new (GST_TYPE_V4L2_BUFFER);
GST_LOG_OBJECT (pool->v4l2elem, "creating buffer %u, %p in pool %p", index,
ret, pool);
ret->pool =
(GstV4l2BufferPool *) gst_mini_object_ref (GST_MINI_OBJECT (pool));
ret->vbuffer.index = index;
ret->vbuffer.type = pool->type;
ret->vbuffer.memory = V4L2_MEMORY_MMAP;
if (v4l2_ioctl (pool->video_fd, VIDIOC_QUERYBUF, &ret->vbuffer) < 0)
goto querybuf_failed;
GST_LOG_OBJECT (pool->v4l2elem, " index: %u", ret->vbuffer.index);
GST_LOG_OBJECT (pool->v4l2elem, " type: %d", ret->vbuffer.type);
GST_LOG_OBJECT (pool->v4l2elem, " bytesused: %u", ret->vbuffer.bytesused);
GST_LOG_OBJECT (pool->v4l2elem, " flags: %08x", ret->vbuffer.flags);
GST_LOG_OBJECT (pool->v4l2elem, " field: %d", ret->vbuffer.field);
GST_LOG_OBJECT (pool->v4l2elem, " memory: %d", ret->vbuffer.memory);
if (ret->vbuffer.memory == V4L2_MEMORY_MMAP)
GST_LOG_OBJECT (pool->v4l2elem, " MMAP offset: %u",
ret->vbuffer.m.offset);
GST_LOG_OBJECT (pool->v4l2elem, " length: %u", ret->vbuffer.length);
GST_LOG_OBJECT (pool->v4l2elem, " input: %u", ret->vbuffer.input);
data = (guint8 *) v4l2_mmap (0, ret->vbuffer.length,
PROT_READ | PROT_WRITE, MAP_SHARED, pool->video_fd,
ret->vbuffer.m.offset);
if (data == MAP_FAILED)
goto mmap_failed;
GST_BUFFER_DATA (ret) = data;
GST_BUFFER_SIZE (ret) = ret->vbuffer.length;
GST_BUFFER_FLAG_SET (ret, GST_BUFFER_FLAG_READONLY);
gst_buffer_set_caps (GST_BUFFER (ret), caps);
return ret;
/* ERRORS */
querybuf_failed:
{
gint errnosave = errno;
GST_WARNING ("Failed QUERYBUF: %s", g_strerror (errnosave));
gst_buffer_unref (GST_BUFFER (ret));
errno = errnosave;
return NULL;
}
mmap_failed:
{
gint errnosave = errno;
GST_WARNING ("Failed to mmap: %s", g_strerror (errnosave));
gst_buffer_unref (GST_BUFFER (ret));
errno = errnosave;
return NULL;
}
}
/*
* GstV4l2BufferPool:
*/
static GstMiniObjectClass *buffer_pool_parent_class = NULL;
static void
gst_v4l2_buffer_pool_finalize (GstV4l2BufferPool * pool)
{
g_mutex_free (pool->lock);
pool->lock = NULL;
g_async_queue_unref (pool->avail_buffers);
pool->avail_buffers = NULL;
if (pool->video_fd >= 0)
v4l2_close (pool->video_fd);
if (pool->buffers) {
g_free (pool->buffers);
pool->buffers = NULL;
}
GST_MINI_OBJECT_CLASS (buffer_pool_parent_class)->finalize (GST_MINI_OBJECT
(pool));
}
static void
gst_v4l2_buffer_pool_init (GstV4l2BufferPool * pool, gpointer g_class)
{
pool->lock = g_mutex_new ();
pool->running = FALSE;
pool->num_live_buffers = 0;
}
static void
gst_v4l2_buffer_pool_class_init (gpointer g_class, gpointer class_data)
{
GstMiniObjectClass *mini_object_class = GST_MINI_OBJECT_CLASS (g_class);
buffer_pool_parent_class = g_type_class_peek_parent (g_class);
mini_object_class->finalize = (GstMiniObjectFinalizeFunction)
gst_v4l2_buffer_pool_finalize;
}
GType
gst_v4l2_buffer_pool_get_type (void)
{
static GType _gst_v4l2_buffer_pool_type;
if (G_UNLIKELY (_gst_v4l2_buffer_pool_type == 0)) {
static const GTypeInfo v4l2_buffer_pool_info = {
sizeof (GstBufferClass),
NULL,
NULL,
gst_v4l2_buffer_pool_class_init,
NULL,
NULL,
sizeof (GstV4l2BufferPool),
0,
(GInstanceInitFunc) gst_v4l2_buffer_pool_init,
NULL
};
_gst_v4l2_buffer_pool_type = g_type_register_static (GST_TYPE_MINI_OBJECT,
"GstV4l2BufferPool", &v4l2_buffer_pool_info, 0);
}
return _gst_v4l2_buffer_pool_type;
}
/* this is somewhat of a hack.. but better to keep the hack in
* one place than copy/pasting it around..
*/
static GstV4l2Object *
get_v4l2_object (GstElement * v4l2elem)
{
GstV4l2Object *v4l2object = NULL;
if (GST_IS_V4L2SRC (v4l2elem)) {
v4l2object = (GST_V4L2SRC (v4l2elem))->v4l2object;
} else if (GST_IS_V4L2SINK (v4l2elem)) {
v4l2object = (GST_V4L2SINK (v4l2elem))->v4l2object;
} else {
GST_ERROR_OBJECT (v4l2elem, "unknown v4l2 element");
}
return v4l2object;
}
/**
* Construct a new buffer pool
*
* @v4l2elem the v4l2 element (src or sink) that owns this pool
* @fd the video device file descriptor
* @num_buffers the requested number of buffers in the pool
* @caps the caps to set on the buffer
* @requeuebuf if <code>TRUE</code>, and if the pool is still in the
* <code>running</code> state, a buffer with no remaining references
* is immediately passed back to v4l2 (<code>VIDIOC_QBUF</code>),
* otherwise it is returned to the pool of available buffers
* (which can be accessed via <code>gst_v4l2_buffer_pool_get()</code>.
*/
GstV4l2BufferPool *
gst_v4l2_buffer_pool_new (GstElement * v4l2elem, gint fd, gint num_buffers,
GstCaps * caps, gboolean requeuebuf, enum v4l2_buf_type type)
{
GstV4l2BufferPool *pool;
gint n;
struct v4l2_requestbuffers breq;
pool = (GstV4l2BufferPool *) gst_mini_object_new (GST_TYPE_V4L2_BUFFER_POOL);
pool->video_fd = v4l2_dup (fd);
if (pool->video_fd < 0)
goto dup_failed;
/* first, lets request buffers, and see how many we can get: */
GST_DEBUG_OBJECT (v4l2elem, "STREAMING, requesting %d MMAP buffers",
num_buffers);
memset (&breq, 0, sizeof (struct v4l2_requestbuffers));
breq.type = type;
breq.count = num_buffers;
breq.memory = V4L2_MEMORY_MMAP;
if (v4l2_ioctl (fd, VIDIOC_REQBUFS, &breq) < 0)
goto reqbufs_failed;
GST_LOG_OBJECT (v4l2elem, " count: %u", breq.count);
GST_LOG_OBJECT (v4l2elem, " type: %d", breq.type);
GST_LOG_OBJECT (v4l2elem, " memory: %d", breq.memory);
if (breq.count < GST_V4L2_MIN_BUFFERS)
goto no_buffers;
if (num_buffers != breq.count) {
GST_WARNING_OBJECT (v4l2elem, "using %u buffers instead", breq.count);
num_buffers = breq.count;
}
pool->v4l2elem = v4l2elem;
pool->requeuebuf = requeuebuf;
pool->type = type;
pool->buffer_count = num_buffers;
pool->buffers = g_new0 (GstV4l2Buffer *, num_buffers);
pool->avail_buffers = g_async_queue_new ();
/* now, map the buffers: */
for (n = 0; n < num_buffers; n++) {
pool->buffers[n] = gst_v4l2_buffer_new (pool, n, caps);
if (!pool->buffers[n])
goto buffer_new_failed;
pool->num_live_buffers++;
g_async_queue_push (pool->avail_buffers, pool->buffers[n]);
}
return pool;
/* ERRORS */
dup_failed:
{
gint errnosave = errno;
gst_mini_object_unref (GST_MINI_OBJECT (pool));
errno = errnosave;
return NULL;
}
reqbufs_failed:
{
GstV4l2Object *v4l2object = get_v4l2_object (v4l2elem);
GST_ELEMENT_ERROR (v4l2elem, RESOURCE, READ,
(_("Could not get buffers from device '%s'."),
v4l2object->videodev),
("error requesting %d buffers: %s", num_buffers, g_strerror (errno)));
return NULL;
}
no_buffers:
{
GstV4l2Object *v4l2object = get_v4l2_object (v4l2elem);
GST_ELEMENT_ERROR (v4l2elem, RESOURCE, READ,
(_("Could not get enough buffers from device '%s'."),
v4l2object->videodev),
("we received %d from device '%s', we want at least %d",
breq.count, v4l2object->videodev, GST_V4L2_MIN_BUFFERS));
return NULL;
}
buffer_new_failed:
{
gint errnosave = errno;
gst_v4l2_buffer_pool_destroy (pool);
errno = errnosave;
return NULL;
}
}
void
gst_v4l2_buffer_pool_destroy (GstV4l2BufferPool * pool)
{
gint n;
GST_V4L2_BUFFER_POOL_LOCK (pool);
pool->running = FALSE;
GST_V4L2_BUFFER_POOL_UNLOCK (pool);
GST_DEBUG_OBJECT (pool->v4l2elem, "destroy pool");
/* after this point, no more buffers will be queued or dequeued; no buffer
* from pool->buffers that is NULL will be set to a buffer, and no buffer that
* is not NULL will be pushed out. */
/* miniobjects have no dispose, so they can't break ref-cycles, as buffers ref
* the pool, we need to unref the buffer to properly finalize te pool */
for (n = 0; n < pool->buffer_count; n++) {
GstBuffer *buf;
GST_V4L2_BUFFER_POOL_LOCK (pool);
buf = GST_BUFFER (pool->buffers[n]);
GST_V4L2_BUFFER_POOL_UNLOCK (pool);
if (buf)
/* we own the ref if the buffer is in pool->buffers; drop it. */
gst_buffer_unref (buf);
}
gst_mini_object_unref (GST_MINI_OBJECT (pool));
}
/**
* Get an available buffer in the pool
*
* @pool the "this" object
*/
GstV4l2Buffer *
gst_v4l2_buffer_pool_get (GstV4l2BufferPool * pool)
{
GstV4l2Buffer *buf = g_async_queue_try_pop (pool->avail_buffers);
if (buf)
GST_BUFFER_SIZE (buf) = buf->vbuffer.length;
pool->running = TRUE;
return buf;
}
/**
* Queue a buffer to the driver
*
* @pool the "this" object
* @buf the buffer to queue
*/
gboolean
gst_v4l2_buffer_pool_qbuf (GstV4l2BufferPool * pool, GstV4l2Buffer * buf)
{
GST_LOG_OBJECT (pool->v4l2elem, "enqueue pool buffer %d", buf->vbuffer.index);
if (v4l2_ioctl (pool->video_fd, VIDIOC_QBUF, &buf->vbuffer) < 0)
return FALSE;
pool->num_live_buffers--;
GST_DEBUG_OBJECT (pool->v4l2elem, "num_live_buffers--: %d",
pool->num_live_buffers);
return TRUE;
}
/**
* Dequeue a buffer from the driver. Some generic error handling is done in
* this function, but any error handling specific to v4l2src (capture) or
* v4l2sink (output) can be done outside this function by checking 'errno'
*
* @pool the "this" object
*/
GstV4l2Buffer *
gst_v4l2_buffer_pool_dqbuf (GstV4l2BufferPool * pool)
{
GstV4l2Object *v4l2object = get_v4l2_object (pool->v4l2elem);
GstV4l2Buffer *pool_buffer;
struct v4l2_buffer buffer;
memset (&buffer, 0x00, sizeof (buffer));
buffer.type = pool->type;
buffer.memory = V4L2_MEMORY_MMAP;
if (v4l2_ioctl (pool->video_fd, VIDIOC_DQBUF, &buffer) >= 0) {
GST_V4L2_BUFFER_POOL_LOCK (pool);
/* get our GstBuffer with that index from the pool, if the buffer was
* outstanding we have a serious problem.
*/
pool_buffer = pool->buffers[buffer.index];
if (pool_buffer == NULL) {
GST_ELEMENT_ERROR (pool->v4l2elem, RESOURCE, FAILED,
(_("Failed trying to get video frames from device '%s'."),
v4l2object->videodev),
(_("No free buffers found in the pool at index %d."), buffer.index));
GST_V4L2_BUFFER_POOL_UNLOCK (pool);
return NULL;
}
GST_LOG_OBJECT (pool->v4l2elem,
"grabbed frame %d (ix=%d), flags %08x, pool-ct=%d, buffer=%p",
buffer.sequence, buffer.index, buffer.flags, pool->num_live_buffers,
pool_buffer);
pool->num_live_buffers++;
GST_DEBUG_OBJECT (pool->v4l2elem, "num_live_buffers++: %d",
pool->num_live_buffers);
GST_V4L2_BUFFER_POOL_UNLOCK (pool);
/* this can change at every frame, esp. with jpeg */
GST_BUFFER_SIZE (pool_buffer) = buffer.bytesused;
return pool_buffer;
}
GST_WARNING_OBJECT (pool->v4l2elem,
"problem grabbing frame %d (ix=%d), pool-ct=%d, buf.flags=%d",
buffer.sequence, buffer.index,
GST_MINI_OBJECT_REFCOUNT (pool), buffer.flags);
switch (errno) {
case EAGAIN:
GST_WARNING_OBJECT (pool->v4l2elem,
"Non-blocking I/O has been selected using O_NONBLOCK and"
" no buffer was in the outgoing queue. device %s",
v4l2object->videodev);
break;
case EINVAL:
GST_ELEMENT_ERROR (pool->v4l2elem, RESOURCE, FAILED,
(_("Failed trying to get video frames from device '%s'."),
v4l2object->videodev),
(_("The buffer type is not supported, or the index is out of bounds,"
" or no buffers have been allocated yet, or the userptr"
" or length are invalid. device %s"), v4l2object->videodev));
break;
case ENOMEM:
GST_ELEMENT_ERROR (pool->v4l2elem, RESOURCE, FAILED,
(_("Failed trying to get video frames from device '%s'. Not enough memory."), v4l2object->videodev), (_("insufficient memory to enqueue a user pointer buffer. device %s."), v4l2object->videodev));
break;
case EIO:
GST_INFO_OBJECT (pool->v4l2elem,
"VIDIOC_DQBUF failed due to an internal error."
" Can also indicate temporary problems like signal loss."
" Note the driver might dequeue an (empty) buffer despite"
" returning an error, or even stop capturing."
" device %s", v4l2object->videodev);
/* have we de-queued a buffer ? */
if (!(buffer.flags & (V4L2_BUF_FLAG_QUEUED | V4L2_BUF_FLAG_DONE))) {
GST_DEBUG_OBJECT (pool->v4l2elem, "reenqueing buffer");
/* FIXME ... should we do something here? */
}
break;
case EINTR:
GST_WARNING_OBJECT (pool->v4l2elem,
"could not sync on a buffer on device %s", v4l2object->videodev);
break;
default:
GST_WARNING_OBJECT (pool->v4l2elem,
"Grabbing frame got interrupted on %s unexpectedly. %d: %s.",
v4l2object->videodev, errno, g_strerror (errno));
break;
}
return NULL;
}
/**
* gst_v4l2_buffer_pool_available_buffers:
* Returns the number of buffers available to the driver, ie. buffers that
* have been QBUF'd but not yet DQBUF'd.
*/
gint
gst_v4l2_buffer_pool_available_buffers (GstV4l2BufferPool * pool)
{
return pool->buffer_count - pool->num_live_buffers;
}