/* GStreamer * * Copyright (C) 2001-2002 Ronald Bultje * 2006 Edgard Lima * 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 #endif #ifndef _GNU_SOURCE # define _GNU_SOURCE /* O_CLOEXEC */ #endif #include #include #include #include #include "gst/video/video.h" #include "gst/video/gstvideometa.h" #include "gst/video/gstvideopool.h" #include "gst/allocators/gstdmabuf.h" #include #include "v4l2_calls.h" #include "gst/gst-i18n-plugin.h" #include 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[] = { GST_META_TAG_VIDEO_STR, GST_META_TAG_MEMORY_STR, 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; gint i = 0; meta = GST_V4L2_META_GET (buffer); g_assert (meta != NULL); index = meta->vbuffer.index; for (i = 0; i < meta->n_planes; i++) { GST_LOG_OBJECT (pool, "unmap multiplanar buffer %p idx %d (data %p, len %u, plane %u)", buffer, index, meta->mem[i], meta->vplanes[i].length, i); v4l2_munmap (meta->mem[i], meta->vplanes[i].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; gint i; 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: { if (pool->num_allocated == pool->num_buffers) { struct v4l2_create_buffers create_bufs; memset (&create_bufs, 0, sizeof (struct v4l2_create_buffers)); create_bufs.count = 1; create_bufs.memory = V4L2_MEMORY_MMAP; create_bufs.format.type = obj->type; if (v4l2_ioctl (pool->video_fd, VIDIOC_G_FMT, &create_bufs.format) < 0) goto g_fmt_failed; if (v4l2_ioctl (pool->video_fd, VIDIOC_CREATE_BUFS, &create_bufs) < 0) goto create_bufs_failed; GST_LOG_OBJECT (pool, "created buffer with index: %u", create_bufs.index); pool->num_buffers++; pool->buffers = g_renew (GstBuffer *, pool->buffers, pool->num_buffers); pool->buffers[pool->num_buffers - 1] = NULL; } newbuf = gst_buffer_new (); meta = GST_V4L2_META_ADD (newbuf); index = pool->num_allocated; GST_LOG_OBJECT (pool, "creating buffer %u, %p", index, newbuf); /* prepare the buffer */ memset (&meta->vbuffer, 0x0, sizeof (struct v4l2_buffer)); meta->vbuffer.index = index; meta->vbuffer.type = obj->type; meta->vbuffer.memory = V4L2_MEMORY_MMAP; /* main information */ meta->n_planes = obj->n_v4l2_planes; /* prepare the planes of the buffer */ if (V4L2_TYPE_IS_MULTIPLANAR (obj->type)) { /* length is the number of elements in the * vplanes array */ meta->vbuffer.length = obj->n_v4l2_planes; meta->vbuffer.m.planes = meta->vplanes; } /* the buffer is prepared, now fill in it with meaningful values */ if (v4l2_ioctl (pool->video_fd, VIDIOC_QUERYBUF, &meta->vbuffer) < 0) goto querybuf_failed; /* in non MPLANE mode we emulate one plane in order to * factorize the code */ if (!V4L2_TYPE_IS_MULTIPLANAR (obj->type)) { /* here meta->n_planes == 1 */ meta->vplanes[0].length = meta->vbuffer.length; meta->vplanes[0].bytesused = meta->vbuffer.bytesused; meta->vplanes[0].m.mem_offset = meta->vbuffer.m.offset; meta->vplanes[0].data_offset = 0; } GST_LOG_OBJECT (pool, " index: %u", meta->vbuffer.index); GST_LOG_OBJECT (pool, " type: %d", meta->vbuffer.type); 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); GST_LOG_OBJECT (pool, " planes: %d", meta->n_planes); #ifndef GST_DISABLE_GST_DEBUG if (meta->vbuffer.memory == V4L2_MEMORY_MMAP) { for (i = 0; i < meta->n_planes; i++) { GST_LOG_OBJECT (pool, " bytesused: %u, plane: %u", meta->vplanes[i].bytesused, i); GST_LOG_OBJECT (pool, " MMAP offset: %u, plane: %u", meta->vplanes[i].m.mem_offset, i); } } #endif if (obj->mode == GST_V4L2_IO_MMAP) { /* append one gstmemory for each plane */ for (i = 0; i < meta->n_planes; i++) { meta->mem[i] = v4l2_mmap (0, meta->vplanes[i].length, PROT_READ | PROT_WRITE, MAP_SHARED, pool->video_fd, meta->vplanes[i].m.mem_offset); if (meta->mem[i] == MAP_FAILED) goto mmap_failed; GST_LOG_OBJECT (pool, " buffer length %d, data offset %d, plane %d", meta->vplanes[i].length, meta->vplanes[i].data_offset, i); gst_buffer_append_memory (newbuf, gst_memory_new_wrapped (GST_MEMORY_FLAG_NO_SHARE, meta->mem[i], meta->vplanes[i].length, meta->vplanes[i].data_offset, meta->vplanes[i].length, NULL, NULL)); } } if (obj->mode == GST_V4L2_IO_DMABUF) { struct v4l2_exportbuffer expbuf; memset (&expbuf, 0, sizeof (struct v4l2_exportbuffer)); expbuf.type = meta->vbuffer.type; expbuf.index = meta->vbuffer.index; expbuf.flags = O_CLOEXEC; for (i = 0; i < meta->n_planes; i++) { expbuf.plane = i; if (v4l2_ioctl (pool->video_fd, VIDIOC_EXPBUF, &expbuf) < 0) goto expbuf_failed; gst_buffer_append_memory (newbuf, gst_dmabuf_allocator_alloc (pool->allocator, expbuf.fd, meta->vplanes[i].length)); } meta->vbuffer.memory = V4L2_MEMORY_DMABUF; /* in non-MPLANE mode our meta is not automatically updated * because the plane is emulated (not referenced by * meta->vbuffer) */ if (!V4L2_TYPE_IS_MULTIPLANAR (obj->type)) meta->vplanes[0].m.fd = meta->vbuffer.m.fd; } /* 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_gst_planes, offs, i, stride[GST_VIDEO_MAX_PLANES]; width = GST_VIDEO_INFO_WIDTH (info); height = GST_VIDEO_INFO_HEIGHT (info); /* n_gst_planes is the number of planes * (RGB: 1, YUY2: 1, NV12: 2, I420: 3) * It's greater or equal than the number of v4l2 planes. */ n_gst_planes = GST_VIDEO_INFO_N_PLANES (info); /* the basic are common between MPLANE mode and non MPLANE mode * except a special case inside the loop at the end */ offs = 0; for (i = 0; i < n_gst_planes; i++) { GST_DEBUG_OBJECT (pool, "adding video meta, bytesperline %d", obj->bytesperline[i]); offset[i] = offs; if (GST_VIDEO_FORMAT_INFO_IS_TILED (finfo)) { guint x_tiles, y_tiles, ws, hs, tile_height; ws = GST_VIDEO_FORMAT_INFO_TILE_WS (finfo); hs = GST_VIDEO_FORMAT_INFO_TILE_HS (finfo); tile_height = 1 << hs; x_tiles = obj->bytesperline[i] >> ws; y_tiles = GST_VIDEO_FORMAT_INFO_SCALE_HEIGHT (finfo, i, GST_ROUND_UP_N (height, tile_height) >> hs); stride[i] = GST_VIDEO_TILE_MAKE_STRIDE (x_tiles, y_tiles); } else { stride[i] = obj->bytesperline[i]; } /* when using multiplanar mode and if there is more then one v4l * plane for each gst plane */ if (V4L2_TYPE_IS_MULTIPLANAR (obj->type) && meta->n_planes > 1) /* non_contiguous case here so we have to make sure that gst goes to the * next plane (using default gstvideometa.c::default_map). * And the next plane is after length bytes of the previous one from * the gst buffer point of view. */ offs += meta->vplanes[i].length; else offs += obj->bytesperline[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_gst_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 */ g_fmt_failed: { gint errnosave = errno; GST_WARNING ("Failed G_FMT: %s", g_strerror (errnosave)); errno = errnosave; return GST_FLOW_ERROR; } create_bufs_failed: { gint errnosave = errno; GST_WARNING ("Failed CREATE_BUFS: %s", g_strerror (errnosave)); errno = errnosave; return GST_FLOW_ERROR; } 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; } expbuf_failed: { gint errnosave = errno; GST_WARNING ("Failed EXPBUF: %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; GstAllocator *allocator; GstAllocationParams params; 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) { /* in non MPLANE mode, there is only one bytesperline field */ gint nb_checked_planes = V4L2_TYPE_IS_MULTIPLANAR (obj->type) ? GST_VIDEO_INFO_N_PLANES (&obj-> info) : 1; gint stride = 0; gint i = 0; for (i = 0; i < nb_checked_planes; i++) { /* we don't have video metadata, and we are dealing with raw video, * see if the strides are compatible */ stride = GST_VIDEO_INFO_PLANE_STRIDE (&obj->info, i); if (GST_VIDEO_FORMAT_INFO_IS_TILED (obj->info.finfo)) { stride = GST_VIDEO_TILE_X_TILES (stride) << GST_VIDEO_FORMAT_INFO_TILE_WS ((obj->info.finfo)); } GST_DEBUG_OBJECT (pool, "no videometadata, checking strides %d and %u", stride, obj->bytesperline[i]); if (stride != obj->bytesperline[i]) 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; /* FIXME Check alignement, and S_FMT with new size if different */ if (!gst_buffer_pool_config_get_allocator (config, &allocator, ¶ms)) goto wrong_config; GST_DEBUG_OBJECT (pool, "config %" GST_PTR_FORMAT, config); if (obj->mode == GST_V4L2_IO_DMABUF) allocator = gst_dmabuf_allocator_new (); else if (allocator) gst_object_ref (allocator); if (pool->allocator) gst_object_unref (pool->allocator); pool->allocator = 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[0]); return FALSE; } wrong_config: { GST_ERROR_OBJECT (pool, "invalid config %" GST_PTR_FORMAT, config); 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; GstStructure *config; GstCaps *caps; guint size, num_buffers, min_buffers, max_buffers, copy_threshold; struct v4l2_requestbuffers breq; config = gst_buffer_pool_get_config (bpool); if (!gst_buffer_pool_config_get_params (config, &caps, &size, &min_buffers, &max_buffers)) goto wrong_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 = MAX (4, min_buffers); 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; } /* FIXME try to call CREATEBUFS with count 0 to check if max shall * remain 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; gst_buffer_pool_config_set_params (config, caps, size, min_buffers, max_buffers); GST_BUFFER_POOL_CLASS (parent_class)->set_config (bpool, config); 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 (!V4L2_TYPE_IS_OUTPUT (obj->type)) if (!start_streaming (pool)) goto start_failed; gst_poll_set_flushing (obj->poll, FALSE); return TRUE; /* ERRORS */ 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; } start_failed: { GST_ERROR_OBJECT (pool, "failed to start streaming"); return FALSE; } } static void gst_v4l2_buffer_pool_free_buffers (GstV4l2BufferPool * pool) { if (pool->num_buffers > 0) { struct v4l2_requestbuffers breq; memset (&breq, 0, sizeof (struct v4l2_requestbuffers)); breq.type = pool->obj->type; breq.count = 0; breq.memory = V4L2_MEMORY_MMAP; if (v4l2_ioctl (pool->video_fd, VIDIOC_REQBUFS, &breq) < 0) { GST_ERROR_OBJECT (pool, "error releasing buffers: %s", g_strerror (errno)); } pool->num_buffers = 0; } } static gboolean stop_streaming (GstV4l2BufferPool * pool) { GstV4l2Object *obj = pool->obj; GST_DEBUG_OBJECT (pool, "stopping stream"); gst_poll_set_flushing (obj->poll, TRUE); if (!pool->streaming) { /* it avoid error: STREAMOFF 22 (Invalid argument) when * attempting to stop a stream not previously started */ GST_DEBUG_OBJECT (pool, "no need to stop, was not previously started"); return TRUE; } 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, "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; return TRUE; /* ERRORS */ stop_failed: { GST_ERROR_OBJECT (pool, "error with STREAMOFF %d (%s)", errno, g_strerror (errno)); 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_buffers; n++) { if (pool->buffers[n]) gst_v4l2_buffer_pool_free_buffer (bpool, pool->buffers[n]); } pool->num_queued = 0; g_free (pool->buffers); pool->buffers = NULL; gst_v4l2_buffer_pool_free_buffers (pool); 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; gint i = 0; 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; /* this field is common to MPLANE and not MPLANE */ meta->vbuffer.bytesused = gst_buffer_get_size (buf); for (i = 0; i < meta->n_planes; i++) { meta->vplanes[i].bytesused = gst_buffer_get_sizes_range (buf, i, 1, NULL, NULL); GST_LOG_OBJECT (pool, "enqueue buffer %p, index:%d, queued:%d, flags:%08x mem:%p used:%d, plane:%d", buf, index, pool->num_queued, meta->vbuffer.flags, meta->mem[i], meta->vplanes[i].bytesused, i); } 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; struct v4l2_plane vplanes[GST_VIDEO_MAX_PLANES]; GstV4l2Object *obj = pool->obj; GstClockTime timestamp; GstV4l2Meta *meta; gint i; if ((res = gst_v4l2_object_poll (obj)) != GST_FLOW_OK) goto poll_error; /* prepare the buffer */ memset (&vbuffer, 0x00, sizeof (vbuffer)); vbuffer.type = obj->type; if (obj->mode == GST_V4L2_IO_DMABUF) vbuffer.memory = V4L2_MEMORY_DMABUF; else vbuffer.memory = V4L2_MEMORY_MMAP; /* prepare the planes of the buffer */ if (V4L2_TYPE_IS_MULTIPLANAR (obj->type)) { /* length is the number of elements in the * vplanes array */ vbuffer.length = obj->n_v4l2_planes; vbuffer.m.planes = vplanes; } /* the buffer is prepared, now fill in it with meaningful values */ 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); meta = GST_V4L2_META_GET (outbuf); g_assert (meta != NULL); /* The size can change at every frame, esp. with jpeg. The GstMemory * inside the GstBuffer could have been changed by some other * element. So update our meta */ if (obj->type == V4L2_BUF_TYPE_VIDEO_CAPTURE || obj->type == V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE) { /* this field is common to MPLANE and not MPLANE */ meta->vbuffer.length = vbuffer.length; meta->vbuffer.bytesused = vbuffer.bytesused; if (obj->type == V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE) { for (i = 0; i < meta->n_planes; i++) { /* the following also update meta->vbuffer.m.planes[i].length */ meta->vplanes[i].length = vbuffer.m.planes[i].length; /* the following also update meta->vbuffer.m.planes[i].bytesused */ meta->vplanes[i].bytesused = vbuffer.m.planes[i].bytesused; /* the following also update meta->vbuffer.m.planes[i].data_offset */ meta->vplanes[i].data_offset = vbuffer.m.planes[i].data_offset; } } else { meta->vplanes[0].length = vbuffer.length; meta->vplanes[0].bytesused = vbuffer.bytesused; meta->vplanes[0].data_offset = 0; } } #ifndef GST_DISABLE_GST_DEBUG for (i = 0; i < meta->n_planes; i++) { GST_LOG_OBJECT (pool, "dequeued buffer %p seq:%d (ix=%d), mem %p used %d, plane=%d, flags %08x, ts %" GST_TIME_FORMAT ", pool-queued=%d, buffer=%p", outbuf, vbuffer.sequence, vbuffer.index, meta->mem[i], meta->vplanes[i].bytesused, i, vbuffer.flags, GST_TIME_ARGS (timestamp), pool->num_queued, outbuf); } #endif /* 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_INTERLACED); GST_BUFFER_FLAG_SET (outbuf, GST_VIDEO_BUFFER_FLAG_TFF); } else if (vbuffer.field == V4L2_FIELD_INTERLACED_BT) { GST_BUFFER_FLAG_SET (outbuf, GST_VIDEO_BUFFER_FLAG_INTERLACED); GST_BUFFER_FLAG_UNSET (outbuf, GST_VIDEO_BUFFER_FLAG_TFF); } else { GST_BUFFER_FLAG_UNSET (outbuf, GST_VIDEO_BUFFER_FLAG_INTERLACED); GST_BUFFER_FLAG_UNSET (outbuf, GST_VIDEO_BUFFER_FLAG_TFF); } if (GST_VIDEO_INFO_FORMAT (&obj->info) == GST_VIDEO_FORMAT_ENCODED) { if (vbuffer.flags & V4L2_BUF_FLAG_KEYFRAME) GST_BUFFER_FLAG_UNSET (outbuf, GST_BUFFER_FLAG_DELTA_UNIT); else GST_BUFFER_FLAG_SET (outbuf, GST_BUFFER_FLAG_DELTA_UNIT); } /* The size can change at every frame, esp. with jpeg. The GstMemory * inside the GstBuffer could have been changed by some other * element, so just put back the original one. We always set it as * no share, so if it's not there, it's not used at all. */ if (obj->type == V4L2_BUF_TYPE_VIDEO_CAPTURE || obj->type == V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE) { gst_buffer_remove_all_memory (outbuf); for (i = 0; i < meta->n_planes; i++) { gst_buffer_append_memory (outbuf, gst_memory_new_wrapped (GST_MEMORY_FLAG_NO_SHARE, meta->mem[i], meta->vplanes[i].length, meta->vplanes[i].data_offset, meta->vplanes[i].bytesused, NULL, NULL)); } } 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: 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 = 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; if (pool->can_alloc) { if (GST_BUFFER_POOL_CLASS (parent_class)->acquire_buffer (bpool, ©, params) == GST_FLOW_OK) { gst_v4l2_buffer_pool_release_buffer (bpool, copy); break; } else { pool->can_alloc = FALSE; } } /* copy the buffer */ copy = gst_buffer_copy_region (*buffer, GST_BUFFER_COPY_ALL | GST_BUFFER_COPY_DEEP, 0, -1); 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: 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 = 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: case V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE: /* 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: case V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE: 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; guint index; meta = GST_V4L2_META_GET (buffer); g_assert (meta != NULL); index = meta->vbuffer.index; if (pool->buffers[index] == NULL) { GST_LOG_OBJECT (pool, "buffer %u not queued, putting on free list", index); /* reset to the full length, in case it was changed */ if (V4L2_TYPE_IS_MULTIPLANAR (obj->type)) { gint i = 0; gint total_length = 0; for (i = 0; i < meta->n_planes; i++) total_length += meta->vplanes[i].length; if (total_length != gst_buffer_get_size (buffer) && obj->info.finfo->n_planes > 1) { /* FIXME if the lengths has actually changed it may require * to restore the sizes of the individual memories and * re-add them */ GST_WARNING_OBJECT (pool, "lengths changed, more work required"); } gst_buffer_resize (buffer, 0, total_length); } else { gst_buffer_resize (buffer, 0, meta->vbuffer.length); } /* 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 %u is queued", index); } 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); gst_v4l2_buffer_pool_free_buffers (pool); if (pool->video_fd >= 0) v4l2_close (pool->video_fd); if (pool->allocator) gst_object_unref (pool->allocator); g_free (pool->buffers); gst_object_unref (pool->obj->element); 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 *config; gboolean res = FALSE; 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; pool->can_alloc = TRUE; config = gst_buffer_pool_get_config (GST_BUFFER_POOL_CAST (pool)); gst_buffer_pool_config_set_params (config, caps, obj->sizeimage, 2, 0); res = gst_buffer_pool_set_config (GST_BUFFER_POOL_CAST (pool), config); if (!res) goto config_failed; gst_object_ref (obj->element); return GST_BUFFER_POOL (pool); /* ERRORS */ dup_failed: { GST_DEBUG ("failed to dup fd %d (%s)", errno, g_strerror (errno)); return NULL; } config_failed: { GST_WARNING ("failed to set pool config"); 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: 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: { 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: 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_DMABUF: case GST_V4L2_IO_MMAP: { GstBuffer *to_queue; if (buf->pool == bpool) { /* nothing, we can queue directly */ to_queue = gst_buffer_ref (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_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) { 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) { gst_buffer_unref (to_queue); goto done; } /* release the rendered buffer back into the pool. This wakes up any * thread waiting for a buffer in _acquire(). If the buffer still has * a pool then this will happen when the refcount reaches 0 */ if (!out->pool) gst_v4l2_buffer_pool_release_buffer (bpool, out); } gst_buffer_unref (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_flush: * @bpool: a #GstBufferPool * * First, set obj->poll to be flushing * Call STREAMOFF to clear QUEUED flag on every driver buffers. * Then release all buffers that are in pool->buffers array. * Finally call STREAMON if CAPTURE type * The caller is responsible to unset flushing on obj->pool * * Returns: TRUE on success. */ gboolean gst_v4l2_buffer_pool_flush (GstV4l2BufferPool * pool) { GstBufferPool *bpool = GST_BUFFER_POOL_CAST (pool); GstV4l2Object *obj = pool->obj; gint i = 0; GST_DEBUG_OBJECT (pool, "flush"); stop_streaming (pool); switch (obj->type) { case V4L2_BUF_TYPE_VIDEO_CAPTURE: case V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE: case V4L2_BUF_TYPE_VIDEO_OUTPUT: case V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE: switch (obj->mode) { case GST_V4L2_IO_RW: break; case GST_V4L2_IO_MMAP: case GST_V4L2_IO_USERPTR: case GST_V4L2_IO_DMABUF: { for (i = 0; i < pool->num_buffers; i++) { GstBuffer *buf = pool->buffers[i]; if (buf) { /* it's necessary to set to NULL before to call * gst_v4l2_buffer_pool_release_buffer * otherwise it won't go back to the pool */ pool->buffers[i] = NULL; /* dicrease counter */ pool->num_queued--; /* in CAPTURE mode the pool->num_queued will be re-incremented * because the buffers are queued when released */ if (buf->pool) gst_buffer_unref (buf); else gst_v4l2_buffer_pool_release_buffer (bpool, buf); } } /* do not set pool->num_queued to 0 because * the buffers are queued when released */ break; } default: g_assert_not_reached (); break; } break; default: g_assert_not_reached (); break; } /* we can start capturing now, we wait for the playback * case until we queued the first buffer */ if (!V4L2_TYPE_IS_OUTPUT (obj->type)) if (!start_streaming (pool)) goto start_failed; return TRUE; /* ERRORS */ start_failed: { GST_ERROR_OBJECT (pool, "failed to start streaming"); return FALSE; } }