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gstreamer/sys/v4l2/gstv4l2bufferpool.c
Benjamin Gaignard e29ab42922 v4l2: Add support of dmabuf 
v4l has add a new IOCTL to export a buffer by using dmabuf.
This patch allow to use this new IOTCL if it has been defined in videodev2.h
I introduce a new IO mode (GST_V4L2_IO_DMABUF) to enable this way of working.

https://bugzilla.gnome.org/show_bug.cgi?id=693826
2013-02-19 12:57:07 +01:00

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/* 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/
*
* gstv4l2bufferpool.c V4L2 buffer pool class
*
* 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., 51 Franklin St, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include <sys/mman.h>
#include <string.h>
#include <unistd.h>
#if HAVE_DECL_V4L2_MEMORY_DMABUF
#include <fcntl.h>
#endif
#include "gst/video/video.h"
#include "gst/video/gstvideometa.h"
#include "gst/video/gstvideopool.h"
#include "gst/allocators/gstdmabuf.h"
#include <gstv4l2bufferpool.h>
#include "gstv4l2src.h"
#include "gstv4l2sink.h"
#include "v4l2_calls.h"
#include "gst/gst-i18n-plugin.h"
#include <gst/glib-compat-private.h>
/* videodev2.h is not versioned and we can't easily check for the presence
* of enum values at compile time, but the V4L2_CAP_VIDEO_OUTPUT_OVERLAY define
* was added in the same commit as V4L2_FIELD_INTERLACED_{TB,BT} (b2787845) */
#ifndef V4L2_CAP_VIDEO_OUTPUT_OVERLAY
#define V4L2_FIELD_INTERLACED_TB 8
#define V4L2_FIELD_INTERLACED_BT 9
#endif
GST_DEBUG_CATEGORY_EXTERN (v4l2_debug);
#define GST_CAT_DEFAULT v4l2_debug
/*
* GstV4l2Buffer:
*/
GType
gst_v4l2_meta_api_get_type (void)
{
static volatile GType type;
static const gchar *tags[] = { "memory", NULL };
if (g_once_init_enter (&type)) {
GType _type = gst_meta_api_type_register ("GstV4l2MetaAPI", tags);
g_once_init_leave (&type, _type);
}
return type;
}
const GstMetaInfo *
gst_v4l2_meta_get_info (void)
{
static const GstMetaInfo *meta_info = NULL;
if (g_once_init_enter (&meta_info)) {
const GstMetaInfo *meta =
gst_meta_register (gst_v4l2_meta_api_get_type (), "GstV4l2Meta",
sizeof (GstV4l2Meta), (GstMetaInitFunction) NULL,
(GstMetaFreeFunction) NULL, (GstMetaTransformFunction) NULL);
g_once_init_leave (&meta_info, meta);
}
return meta_info;
}
/*
* GstV4l2BufferPool:
*/
#define gst_v4l2_buffer_pool_parent_class parent_class
G_DEFINE_TYPE (GstV4l2BufferPool, gst_v4l2_buffer_pool, GST_TYPE_BUFFER_POOL);
static void gst_v4l2_buffer_pool_release_buffer (GstBufferPool * bpool,
GstBuffer * buffer);
static void
gst_v4l2_buffer_pool_free_buffer (GstBufferPool * bpool, GstBuffer * buffer)
{
GstV4l2BufferPool *pool = GST_V4L2_BUFFER_POOL (bpool);
GstV4l2Object *obj;
obj = pool->obj;
switch (obj->mode) {
case GST_V4L2_IO_RW:
case GST_V4L2_IO_DMABUF:
break;
case GST_V4L2_IO_MMAP:
{
GstV4l2Meta *meta;
gint index;
meta = GST_V4L2_META_GET (buffer);
g_assert (meta != NULL);
index = meta->vbuffer.index;
GST_LOG_OBJECT (pool,
"unmap buffer %p idx %d (data %p, len %u)", buffer,
index, meta->mem, meta->vbuffer.length);
v4l2_munmap (meta->mem, meta->vbuffer.length);
pool->buffers[index] = NULL;
break;
}
case GST_V4L2_IO_USERPTR:
default:
g_assert_not_reached ();
break;
}
gst_buffer_unref (buffer);
}
static GstFlowReturn
gst_v4l2_buffer_pool_alloc_buffer (GstBufferPool * bpool, GstBuffer ** buffer,
GstBufferPoolAcquireParams * params)
{
GstV4l2BufferPool *pool = GST_V4L2_BUFFER_POOL (bpool);
GstBuffer *newbuf;
GstV4l2Meta *meta;
GstV4l2Object *obj;
GstVideoInfo *info;
guint index;
obj = pool->obj;
info = &obj->info;
switch (obj->mode) {
case GST_V4L2_IO_RW:
{
newbuf =
gst_buffer_new_allocate (pool->allocator, pool->size, &pool->params);
break;
}
case GST_V4L2_IO_MMAP:
case GST_V4L2_IO_DMABUF:
{
newbuf = gst_buffer_new ();
meta = GST_V4L2_META_ADD (newbuf);
index = pool->num_allocated;
GST_LOG_OBJECT (pool, "creating buffer %u, %p", index, newbuf);
meta->vbuffer.index = index;
meta->vbuffer.type = obj->type;
meta->vbuffer.memory = V4L2_MEMORY_MMAP;
if (v4l2_ioctl (pool->video_fd, VIDIOC_QUERYBUF, &meta->vbuffer) < 0)
goto querybuf_failed;
GST_LOG_OBJECT (pool, " index: %u", meta->vbuffer.index);
GST_LOG_OBJECT (pool, " type: %d", meta->vbuffer.type);
GST_LOG_OBJECT (pool, " bytesused: %u", meta->vbuffer.bytesused);
GST_LOG_OBJECT (pool, " flags: %08x", meta->vbuffer.flags);
GST_LOG_OBJECT (pool, " field: %d", meta->vbuffer.field);
GST_LOG_OBJECT (pool, " memory: %d", meta->vbuffer.memory);
if (meta->vbuffer.memory == V4L2_MEMORY_MMAP)
GST_LOG_OBJECT (pool, " MMAP offset: %u", meta->vbuffer.m.offset);
if (obj->mode == GST_V4L2_IO_MMAP) {
meta->mem = v4l2_mmap (0, meta->vbuffer.length,
PROT_READ | PROT_WRITE, MAP_SHARED, pool->video_fd,
meta->vbuffer.m.offset);
if (meta->mem == MAP_FAILED)
goto mmap_failed;
gst_buffer_append_memory (newbuf,
gst_memory_new_wrapped (GST_MEMORY_FLAG_NO_SHARE,
meta->mem, meta->vbuffer.length, 0, meta->vbuffer.length, NULL,
NULL));
}
#if HAVE_DECL_V4L2_MEMORY_DMABUF
if (obj->mode == GST_V4L2_IO_DMABUF) {
struct v4l2_exportbuffer expbuf;
expbuf.type = meta->vbuffer.type;
expbuf.index = meta->vbuffer.index;
expbuf.flags = O_CLOEXEC;
if (v4l2_ioctl (pool->video_fd, VIDIOC_EXPBUF, &expbuf) < 0)
goto mmap_failed;
meta->vbuffer.memory = V4L2_MEMORY_DMABUF;
gst_buffer_append_memory (newbuf,
gst_dmabuf_allocator_alloc (pool->allocator, expbuf.fd,
meta->vbuffer.length));
}
#endif
/* add metadata to raw video buffers */
if (pool->add_videometa && info->finfo) {
const GstVideoFormatInfo *finfo = info->finfo;
gsize offset[GST_VIDEO_MAX_PLANES];
gint width, height, n_planes, offs, i, stride[GST_VIDEO_MAX_PLANES];
width = GST_VIDEO_INFO_WIDTH (info);
height = GST_VIDEO_INFO_HEIGHT (info);
n_planes = GST_VIDEO_INFO_N_PLANES (info);
GST_DEBUG_OBJECT (pool, "adding video meta, bytesperline %d",
obj->bytesperline);
offs = 0;
for (i = 0; i < n_planes; i++) {
offset[i] = offs;
stride[i] =
GST_VIDEO_FORMAT_INFO_SCALE_WIDTH (finfo, i, obj->bytesperline);
offs +=
stride[i] * GST_VIDEO_FORMAT_INFO_SCALE_HEIGHT (finfo, i, height);
}
gst_buffer_add_video_meta_full (newbuf, GST_VIDEO_FRAME_FLAG_NONE,
GST_VIDEO_INFO_FORMAT (info), width, height, n_planes,
offset, stride);
}
break;
}
case GST_V4L2_IO_USERPTR:
default:
newbuf = NULL;
g_assert_not_reached ();
}
pool->num_allocated++;
*buffer = newbuf;
return GST_FLOW_OK;
/* ERRORS */
querybuf_failed:
{
gint errnosave = errno;
GST_WARNING ("Failed QUERYBUF: %s", g_strerror (errnosave));
gst_buffer_unref (newbuf);
errno = errnosave;
return GST_FLOW_ERROR;
}
mmap_failed:
{
gint errnosave = errno;
GST_WARNING ("Failed to mmap: %s", g_strerror (errnosave));
gst_buffer_unref (newbuf);
errno = errnosave;
return GST_FLOW_ERROR;
}
}
static gboolean
gst_v4l2_buffer_pool_set_config (GstBufferPool * bpool, GstStructure * config)
{
GstV4l2BufferPool *pool = GST_V4L2_BUFFER_POOL (bpool);
GstV4l2Object *obj = pool->obj;
GstCaps *caps;
guint size, min_buffers, max_buffers, num_buffers, copy_threshold;
GstAllocator *allocator;
GstAllocationParams params;
struct v4l2_requestbuffers breq;
GST_DEBUG_OBJECT (pool, "set config");
pool->add_videometa =
gst_buffer_pool_config_has_option (config,
GST_BUFFER_POOL_OPTION_VIDEO_META);
if (!pool->add_videometa &&
GST_VIDEO_INFO_FORMAT (&obj->info) != GST_VIDEO_FORMAT_ENCODED) {
gint stride;
/* we don't have video metadata, and we are not dealing with raw video,
* see if the strides are compatible */
stride = GST_VIDEO_INFO_PLANE_STRIDE (&obj->info, 0);
GST_DEBUG_OBJECT (pool, "no videometadata, checking strides %d and %u",
stride, obj->bytesperline);
if (stride != obj->bytesperline)
goto missing_video_api;
}
/* parse the config and keep around */
if (!gst_buffer_pool_config_get_params (config, &caps, &size, &min_buffers,
&max_buffers))
goto wrong_config;
if (!gst_buffer_pool_config_get_allocator (config, &allocator, &params))
goto wrong_config;
GST_DEBUG_OBJECT (pool, "config %" GST_PTR_FORMAT, config);
switch (obj->mode) {
case GST_V4L2_IO_RW:
/* we preallocate 1 buffer, this value also instructs the latency
* calculation to have 1 frame latency max */
num_buffers = 1;
copy_threshold = 0;
break;
case GST_V4L2_IO_DMABUF:
case GST_V4L2_IO_MMAP:
{
/* request a reasonable number of buffers when no max specified. We will
* copy when we run out of buffers */
if (max_buffers == 0)
num_buffers = 4;
else
num_buffers = max_buffers;
/* first, lets request buffers, and see how many we can get: */
GST_DEBUG_OBJECT (pool, "starting, requesting %d MMAP buffers",
num_buffers);
memset (&breq, 0, sizeof (struct v4l2_requestbuffers));
breq.type = obj->type;
breq.count = num_buffers;
breq.memory = V4L2_MEMORY_MMAP;
if (v4l2_ioctl (pool->video_fd, VIDIOC_REQBUFS, &breq) < 0)
goto reqbufs_failed;
GST_LOG_OBJECT (pool, " count: %u", breq.count);
GST_LOG_OBJECT (pool, " type: %d", breq.type);
GST_LOG_OBJECT (pool, " memory: %d", breq.memory);
if (breq.count < GST_V4L2_MIN_BUFFERS)
goto no_buffers;
if (num_buffers != breq.count) {
GST_WARNING_OBJECT (pool, "using %u buffers instead", breq.count);
num_buffers = breq.count;
}
/* update min buffers with the amount of buffers we just reserved. We need
* to configure this value in the bufferpool so that the default start
* implementation calls our allocate function */
min_buffers = breq.count;
if (max_buffers == 0 || num_buffers < max_buffers) {
/* if we are asked to provide more buffers than we have allocated, start
* copying buffers when we only have 2 buffers left in the pool */
copy_threshold = 2;
} else {
/* we are certain that we have enough buffers so we don't need to
* copy */
copy_threshold = 0;
}
break;
}
case GST_V4L2_IO_USERPTR:
default:
num_buffers = 0;
copy_threshold = 0;
g_assert_not_reached ();
break;
}
pool->size = size;
pool->num_buffers = num_buffers;
pool->copy_threshold = copy_threshold;
if (obj->mode == GST_V4L2_IO_DMABUF)
allocator = gst_dmabuf_allocator_obtain ();
if (pool->allocator)
gst_object_unref (pool->allocator);
if ((pool->allocator = allocator))
gst_object_ref (allocator);
pool->params = params;
gst_buffer_pool_config_set_params (config, caps, size, min_buffers,
max_buffers);
return GST_BUFFER_POOL_CLASS (parent_class)->set_config (bpool, config);
/* ERRORS */
missing_video_api:
{
GST_ERROR_OBJECT (pool, "missing GstMetaVideo API in config, "
"default stride: %d, wanted stride %u",
GST_VIDEO_INFO_PLANE_STRIDE (&obj->info, 0), obj->bytesperline);
return FALSE;
}
wrong_config:
{
GST_ERROR_OBJECT (pool, "invalid config %" GST_PTR_FORMAT, config);
return FALSE;
}
reqbufs_failed:
{
GST_ERROR_OBJECT (pool,
"error requesting %d buffers: %s", num_buffers, g_strerror (errno));
return FALSE;
}
no_buffers:
{
GST_ERROR_OBJECT (pool,
"we received %d from device '%s', we want at least %d",
breq.count, obj->videodev, GST_V4L2_MIN_BUFFERS);
return FALSE;
}
}
static gboolean
start_streaming (GstV4l2BufferPool * pool)
{
GstV4l2Object *obj = pool->obj;
switch (obj->mode) {
case GST_V4L2_IO_RW:
break;
case GST_V4L2_IO_MMAP:
case GST_V4L2_IO_USERPTR:
case GST_V4L2_IO_DMABUF:
GST_DEBUG_OBJECT (pool, "STREAMON");
if (v4l2_ioctl (pool->video_fd, VIDIOC_STREAMON, &obj->type) < 0)
goto start_failed;
break;
default:
g_assert_not_reached ();
break;
}
pool->streaming = TRUE;
return TRUE;
/* ERRORS */
start_failed:
{
GST_ERROR_OBJECT (pool, "error with STREAMON %d (%s)", errno,
g_strerror (errno));
return FALSE;
}
}
static gboolean
gst_v4l2_buffer_pool_start (GstBufferPool * bpool)
{
GstV4l2BufferPool *pool = GST_V4L2_BUFFER_POOL (bpool);
GstV4l2Object *obj = pool->obj;
pool->obj = obj;
pool->buffers = g_new0 (GstBuffer *, pool->num_buffers);
pool->num_allocated = 0;
/* now, allocate the buffers: */
if (!GST_BUFFER_POOL_CLASS (parent_class)->start (bpool))
goto start_failed;
/* we can start capturing now, we wait for the playback case until we queued
* the first buffer */
if (obj->type == V4L2_BUF_TYPE_VIDEO_CAPTURE)
if (!start_streaming (pool))
goto start_failed;
gst_poll_set_flushing (obj->poll, FALSE);
return TRUE;
/* ERRORS */
start_failed:
{
GST_ERROR_OBJECT (pool, "failed to start streaming");
return FALSE;
}
}
static gboolean
gst_v4l2_buffer_pool_stop (GstBufferPool * bpool)
{
gboolean ret;
GstV4l2BufferPool *pool = GST_V4L2_BUFFER_POOL (bpool);
GstV4l2Object *obj = pool->obj;
guint n;
GST_DEBUG_OBJECT (pool, "stopping pool");
gst_poll_set_flushing (obj->poll, TRUE);
if (pool->streaming) {
switch (obj->mode) {
case GST_V4L2_IO_RW:
break;
case GST_V4L2_IO_MMAP:
case GST_V4L2_IO_USERPTR:
case GST_V4L2_IO_DMABUF:
/* we actually need to sync on all queued buffers but not
* on the non-queued ones */
GST_DEBUG_OBJECT (pool, "STREAMOFF");
if (v4l2_ioctl (pool->video_fd, VIDIOC_STREAMOFF, &obj->type) < 0)
goto stop_failed;
break;
default:
g_assert_not_reached ();
break;
}
pool->streaming = FALSE;
}
/* first free the buffers in the queue */
ret = GST_BUFFER_POOL_CLASS (parent_class)->stop (bpool);
/* then free the remaining buffers */
for (n = 0; n < pool->num_queued; n++) {
gst_v4l2_buffer_pool_free_buffer (bpool, pool->buffers[n]);
}
pool->num_queued = 0;
g_free (pool->buffers);
pool->buffers = NULL;
return ret;
/* ERRORS */
stop_failed:
{
GST_ERROR_OBJECT (pool, "error with STREAMOFF %d (%s)", errno,
g_strerror (errno));
return FALSE;
}
}
static GstFlowReturn
gst_v4l2_object_poll (GstV4l2Object * v4l2object)
{
gint ret;
if (v4l2object->can_poll_device) {
GST_LOG_OBJECT (v4l2object->element, "polling 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_WARNING_OBJECT (v4l2object->element,
"v4l2 device doesn't support polling. Disabling");
v4l2object->can_poll_device = FALSE;
} else {
if (errno != EAGAIN && errno != EINTR)
goto select_error;
}
}
}
return GST_FLOW_OK;
/* ERRORS */
stopped:
{
GST_DEBUG ("stop called");
return GST_FLOW_FLUSHING;
}
select_error:
{
GST_ELEMENT_ERROR (v4l2object->element, RESOURCE, READ, (NULL),
("poll error %d: %s (%d)", ret, g_strerror (errno), errno));
return GST_FLOW_ERROR;
}
}
static GstFlowReturn
gst_v4l2_buffer_pool_qbuf (GstV4l2BufferPool * pool, GstBuffer * buf)
{
GstV4l2Meta *meta;
gint index;
meta = GST_V4L2_META_GET (buf);
if (meta == NULL) {
GST_LOG_OBJECT (pool, "unref copied buffer %p", buf);
/* no meta, it was a copied buffer that we can unref */
gst_buffer_unref (buf);
return GST_FLOW_OK;
}
index = meta->vbuffer.index;
GST_LOG_OBJECT (pool, "enqueue buffer %p, index:%d, queued:%d, flags:%08x",
buf, index, pool->num_queued, meta->vbuffer.flags);
if (pool->buffers[index] != NULL)
goto already_queued;
GST_LOG_OBJECT (pool, "doing QBUF");
if (v4l2_ioctl (pool->video_fd, VIDIOC_QBUF, &meta->vbuffer) < 0)
goto queue_failed;
pool->buffers[index] = buf;
pool->num_queued++;
return GST_FLOW_OK;
/* ERRORS */
already_queued:
{
GST_WARNING_OBJECT (pool, "the buffer was already queued");
return GST_FLOW_ERROR;
}
queue_failed:
{
GST_WARNING_OBJECT (pool, "could not queue a buffer %d (%s)", errno,
g_strerror (errno));
return GST_FLOW_ERROR;
}
}
static GstFlowReturn
gst_v4l2_buffer_pool_dqbuf (GstV4l2BufferPool * pool, GstBuffer ** buffer)
{
GstFlowReturn res;
GstBuffer *outbuf;
struct v4l2_buffer vbuffer;
GstV4l2Object *obj = pool->obj;
GstClockTime timestamp;
if (obj->type == V4L2_BUF_TYPE_VIDEO_CAPTURE) {
/* select works for input devices when data is available. According to the
* specs we can also poll to find out when a frame has been displayed but
* that just seems to lock up here */
if ((res = gst_v4l2_object_poll (obj)) != GST_FLOW_OK)
goto poll_error;
}
memset (&vbuffer, 0x00, sizeof (vbuffer));
vbuffer.type = obj->type;
#if HAVE_DECL_V4L2_MEMORY_DMABUF
if (obj->mode == GST_V4L2_IO_DMABUF)
vbuffer.memory = V4L2_MEMORY_DMABUF;
else
#endif
vbuffer.memory = V4L2_MEMORY_MMAP;
GST_LOG_OBJECT (pool, "doing DQBUF");
if (v4l2_ioctl (pool->video_fd, VIDIOC_DQBUF, &vbuffer) < 0)
goto error;
/* get our GstBuffer with that index from the pool, if the buffer was
* outstanding we have a serious problem.
*/
outbuf = pool->buffers[vbuffer.index];
if (outbuf == NULL)
goto no_buffer;
/* mark the buffer outstanding */
pool->buffers[vbuffer.index] = NULL;
pool->num_queued--;
timestamp = GST_TIMEVAL_TO_TIME (vbuffer.timestamp);
GST_LOG_OBJECT (pool,
"dequeued buffer %p seq:%d (ix=%d), used %d, flags %08x, ts %"
GST_TIME_FORMAT ", pool-queued=%d, buffer=%p", outbuf, vbuffer.sequence,
vbuffer.index, vbuffer.bytesused, vbuffer.flags,
GST_TIME_ARGS (timestamp), pool->num_queued, outbuf);
/* set top/bottom field first if v4l2_buffer has the information */
if (vbuffer.field == V4L2_FIELD_INTERLACED_TB) {
GST_BUFFER_FLAG_SET (outbuf, GST_VIDEO_BUFFER_FLAG_TFF);
}
if (vbuffer.field == V4L2_FIELD_INTERLACED_BT) {
GST_BUFFER_FLAG_UNSET (outbuf, GST_VIDEO_BUFFER_FLAG_TFF);
}
/* this can change at every frame, esp. with jpeg */
if (obj->type == V4L2_BUF_TYPE_VIDEO_CAPTURE)
gst_buffer_resize (outbuf, 0, vbuffer.bytesused);
else
gst_buffer_resize (outbuf, 0, vbuffer.length);
GST_BUFFER_TIMESTAMP (outbuf) = timestamp;
*buffer = outbuf;
return GST_FLOW_OK;
/* ERRORS */
poll_error:
{
GST_DEBUG_OBJECT (pool, "poll error %s", gst_flow_get_name (res));
return res;
}
error:
{
GST_WARNING_OBJECT (pool,
"problem dequeuing frame %d (ix=%d), pool-ct=%d, buf.flags=%d",
vbuffer.sequence, vbuffer.index,
GST_MINI_OBJECT_REFCOUNT (pool), vbuffer.flags);
switch (errno) {
case EAGAIN:
GST_WARNING_OBJECT (pool,
"Non-blocking I/O has been selected using O_NONBLOCK and"
" no buffer was in the outgoing queue. device %s", obj->videodev);
break;
case EINVAL:
GST_ERROR_OBJECT (pool,
"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", obj->videodev);
break;
case ENOMEM:
GST_ERROR_OBJECT (pool,
"insufficient memory to enqueue a user pointer buffer");
break;
case EIO:
GST_INFO_OBJECT (pool,
"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", obj->videodev);
/* have we de-queued a buffer ? */
if (!(vbuffer.flags & (V4L2_BUF_FLAG_QUEUED | V4L2_BUF_FLAG_DONE))) {
GST_DEBUG_OBJECT (pool, "reenqueing buffer");
/* FIXME ... should we do something here? */
}
break;
case EINTR:
GST_WARNING_OBJECT (pool,
"could not sync on a buffer on device %s", obj->videodev);
break;
default:
GST_WARNING_OBJECT (pool,
"Grabbing frame got interrupted on %s unexpectedly. %d: %s.",
obj->videodev, errno, g_strerror (errno));
break;
}
return GST_FLOW_ERROR;
}
no_buffer:
{
GST_ERROR_OBJECT (pool, "No free buffer found in the pool at index %d.",
vbuffer.index);
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);
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_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;
/* 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:
ret = GST_FLOW_ERROR;
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:
ret = GST_FLOW_ERROR;
g_assert_not_reached ();
break;
}
break;
default:
ret = GST_FLOW_ERROR;
g_assert_not_reached ();
break;
}
done:
return ret;
/* ERRORS */
flushing:
{
GST_DEBUG_OBJECT (pool, "We are flushing");
return GST_FLOW_FLUSHING;
}
}
static void
gst_v4l2_buffer_pool_release_buffer (GstBufferPool * bpool, GstBuffer * buffer)
{
GstV4l2BufferPool *pool = GST_V4L2_BUFFER_POOL (bpool);
GstV4l2Object *obj = pool->obj;
GST_DEBUG_OBJECT (pool, "release buffer %p", buffer);
switch (obj->type) {
case V4L2_BUF_TYPE_VIDEO_CAPTURE:
/* capture, put the buffer back in the queue so that we can refill it
* later. */
switch (obj->mode) {
case GST_V4L2_IO_RW:
/* release back in the pool */
GST_BUFFER_POOL_CLASS (parent_class)->release_buffer (bpool, buffer);
break;
case GST_V4L2_IO_DMABUF:
case GST_V4L2_IO_MMAP:
/* queue back in the device */
gst_v4l2_buffer_pool_qbuf (pool, buffer);
break;
case GST_V4L2_IO_USERPTR:
default:
g_assert_not_reached ();
break;
}
break;
case V4L2_BUF_TYPE_VIDEO_OUTPUT:
switch (obj->mode) {
case GST_V4L2_IO_RW:
/* release back in the pool */
GST_BUFFER_POOL_CLASS (parent_class)->release_buffer (bpool, buffer);
break;
case GST_V4L2_IO_MMAP:
{
GstV4l2Meta *meta;
meta = GST_V4L2_META_GET (buffer);
g_assert (meta != NULL);
if (pool->buffers[meta->vbuffer.index] == NULL) {
GST_LOG_OBJECT (pool, "buffer not queued, putting on free list");
/* 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;
}
case GST_V4L2_IO_USERPTR:
default:
g_assert_not_reached ();
break;
}
break;
default:
g_assert_not_reached ();
break;
}
}
static void
gst_v4l2_buffer_pool_finalize (GObject * object)
{
GstV4l2BufferPool *pool = GST_V4L2_BUFFER_POOL (object);
if (pool->video_fd >= 0)
v4l2_close (pool->video_fd);
if (pool->allocator)
gst_object_unref (pool->allocator);
g_free (pool->buffers);
G_OBJECT_CLASS (parent_class)->finalize (object);
}
static void
gst_v4l2_buffer_pool_init (GstV4l2BufferPool * pool)
{
}
static void
gst_v4l2_buffer_pool_class_init (GstV4l2BufferPoolClass * klass)
{
GObjectClass *object_class = G_OBJECT_CLASS (klass);
GstBufferPoolClass *bufferpool_class = GST_BUFFER_POOL_CLASS (klass);
object_class->finalize = gst_v4l2_buffer_pool_finalize;
bufferpool_class->start = gst_v4l2_buffer_pool_start;
bufferpool_class->stop = gst_v4l2_buffer_pool_stop;
bufferpool_class->set_config = gst_v4l2_buffer_pool_set_config;
bufferpool_class->alloc_buffer = gst_v4l2_buffer_pool_alloc_buffer;
bufferpool_class->acquire_buffer = gst_v4l2_buffer_pool_acquire_buffer;
bufferpool_class->release_buffer = gst_v4l2_buffer_pool_release_buffer;
bufferpool_class->free_buffer = gst_v4l2_buffer_pool_free_buffer;
}
/**
* gst_v4l2_buffer_pool_new:
* @obj: the v4l2 object owning the pool
*
* Construct a new buffer pool.
*
* Returns: the new pool, use gst_object_unref() to free resources
*/
GstBufferPool *
gst_v4l2_buffer_pool_new (GstV4l2Object * obj, GstCaps * caps)
{
GstV4l2BufferPool *pool;
GstStructure *s;
gint fd;
fd = v4l2_dup (obj->video_fd);
if (fd < 0)
goto dup_failed;
pool = (GstV4l2BufferPool *) g_object_new (GST_TYPE_V4L2_BUFFER_POOL, NULL);
pool->video_fd = fd;
pool->obj = obj;
s = gst_buffer_pool_get_config (GST_BUFFER_POOL_CAST (pool));
gst_buffer_pool_config_set_params (s, caps, obj->sizeimage, 2, 0);
gst_buffer_pool_set_config (GST_BUFFER_POOL_CAST (pool), s);
return GST_BUFFER_POOL (pool);
/* ERRORS */
dup_failed:
{
GST_DEBUG ("failed to dup fd %d (%s)", errno, g_strerror (errno));
return NULL;
}
}
static GstFlowReturn
gst_v4l2_do_read (GstV4l2BufferPool * pool, GstBuffer * buf)
{
GstFlowReturn res;
GstV4l2Object *obj = pool->obj;
gint amount;
GstMapInfo map;
gint toread;
toread = obj->sizeimage;
GST_LOG_OBJECT (pool, "reading %d bytes into buffer %p", toread, buf);
gst_buffer_map (buf, &map, GST_MAP_WRITE);
do {
if ((res = gst_v4l2_object_poll (obj)) != GST_FLOW_OK)
goto poll_error;
amount = v4l2_read (obj->video_fd, map.data, toread);
if (amount == toread) {
break;
} else if (amount == -1) {
if (errno == EAGAIN || errno == EINTR) {
continue;
} else
goto read_error;
} else {
/* short reads can happen if a signal interrupts the read */
continue;
}
} while (TRUE);
GST_LOG_OBJECT (pool, "read %d bytes", amount);
gst_buffer_unmap (buf, &map);
gst_buffer_resize (buf, 0, amount);
return GST_FLOW_OK;
/* ERRORS */
poll_error:
{
GST_DEBUG ("poll error %s", gst_flow_get_name (res));
goto cleanup;
}
read_error:
{
GST_ELEMENT_ERROR (obj->element, RESOURCE, READ,
(_("Error reading %d bytes from device '%s'."),
toread, obj->videodev), GST_ERROR_SYSTEM);
res = GST_FLOW_ERROR;
goto cleanup;
}
cleanup:
{
gst_buffer_unmap (buf, &map);
gst_buffer_resize (buf, 0, 0);
return res;
}
}
/**
* 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_DMABUF:
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;
}
}
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