/* 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., 59 Temple Place - Suite 330, * Boston, MA 02111-1307, USA. */ #ifdef HAVE_CONFIG_H # include #endif #include #include #include #include "gst/video/video.h" #include "gst/video/gstmetavideo.h" #include #include "gstv4l2src.h" #include "gstv4l2sink.h" #include "v4l2_calls.h" #include "gst/gst-i18n-plugin.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: */ const GstMetaInfo * gst_meta_v4l2_get_info (void) { static const GstMetaInfo *meta_info = NULL; if (meta_info == NULL) { meta_info = gst_meta_register ("GstMetaV4l2", "GstMetaV4l2", sizeof (GstMetaV4l2), (GstMetaInitFunction) NULL, (GstMetaFreeFunction) NULL, (GstMetaCopyFunction) NULL, (GstMetaTransformFunction) NULL); } 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: break; case GST_V4L2_IO_MMAP: { GstMetaV4l2 *meta; gint index; meta = GST_META_V4L2_GET (buffer); g_assert (meta != NULL); index = meta->vbuffer.index; GST_LOG_OBJECT (pool, "mmap buffer %p idx %d (data %p, len %u) freed, unmapping", 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, GstBufferPoolParams * params) { GstV4l2BufferPool *pool = GST_V4L2_BUFFER_POOL (bpool); GstBuffer *newbuf; GstMetaV4l2 *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->align); break; } case GST_V4L2_IO_MMAP: { newbuf = gst_buffer_new (); meta = GST_META_V4L2_ADD (newbuf); index = pool->index; GST_LOG_OBJECT (pool, "creating buffer %u, %p", index, newbuf, pool); 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); GST_LOG_OBJECT (pool, " length: %u", meta->vbuffer.length); GST_LOG_OBJECT (pool, " input: %u", meta->vbuffer.input); 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_take_memory (newbuf, -1, gst_memory_new_wrapped (0, meta->mem, NULL, meta->vbuffer.length, 0, meta->vbuffer.length)); /* add metadata to raw video buffers */ if (info->finfo) { gsize offset[GST_VIDEO_MAX_PLANES]; gint stride[GST_VIDEO_MAX_PLANES]; offset[0] = 0; stride[0] = obj->bytesperline; GST_DEBUG_OBJECT (pool, "adding video meta, stride %d", stride[0]); gst_buffer_add_meta_video_full (newbuf, info->flags, GST_VIDEO_INFO_FORMAT (info), GST_VIDEO_INFO_WIDTH (info), GST_VIDEO_INFO_HEIGHT (info), GST_VIDEO_INFO_N_PLANES (info), offset, stride); } break; } case GST_V4L2_IO_USERPTR: default: g_assert_not_reached (); break; } pool->index++; *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); const GstCaps *caps; guint size, min_buffers, max_buffers; guint prefix, align; GST_DEBUG_OBJECT (pool, "set config"); /* parse the config and keep around */ if (!gst_buffer_pool_config_get (config, &caps, &size, &min_buffers, &max_buffers, &prefix, &align)) goto wrong_config; GST_DEBUG_OBJECT (pool, "config %" GST_PTR_FORMAT, config); pool->size = size; pool->min_buffers = min_buffers; pool->max_buffers = max_buffers; pool->prefix = prefix; pool->align = align; gst_buffer_pool_config_set (config, caps, size, min_buffers, max_buffers, prefix, align); return GST_BUFFER_POOL_CLASS (parent_class)->set_config (bpool, config); wrong_config: { GST_WARNING_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: 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; gint n; struct v4l2_requestbuffers breq; gint min_buffers, max_buffers; min_buffers = pool->min_buffers; max_buffers = pool->max_buffers; switch (obj->mode) { case GST_V4L2_IO_RW: { break; } case GST_V4L2_IO_MMAP: { /* first, lets request buffers, and see how many we can get: */ GST_DEBUG_OBJECT (pool, "starting, requesting %d MMAP buffers", max_buffers); memset (&breq, 0, sizeof (struct v4l2_requestbuffers)); breq.type = obj->type; breq.count = max_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 (max_buffers != breq.count) { GST_WARNING_OBJECT (pool, "using %u buffers instead", breq.count); max_buffers = breq.count; } break; } case GST_V4L2_IO_USERPTR: default: g_assert_not_reached (); break; } pool->obj = obj; pool->max_buffers = max_buffers; pool->buffers = g_new0 (GstBuffer *, max_buffers); pool->index = 0; /* now, allocate the buffers: */ for (n = 0; n < min_buffers; n++) { GstBuffer *buffer; if (gst_v4l2_buffer_pool_alloc_buffer (bpool, &buffer, NULL) != GST_FLOW_OK) goto buffer_new_failed; gst_v4l2_buffer_pool_release_buffer (bpool, buffer); } /* 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; return TRUE; /* ERRORS */ reqbufs_failed: { GST_ERROR_OBJECT (pool, "error requesting %d buffers: %s", max_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; } buffer_new_failed: { GST_ERROR_OBJECT (pool, "failed to create a buffer"); return FALSE; } 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"); if (pool->streaming) { switch (obj->mode) { case GST_V4L2_IO_RW: break; case GST_V4L2_IO_MMAP: case GST_V4L2_IO_USERPTR: /* 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]); } 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_WRONG_STATE; } 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) { GstMetaV4l2 *meta; gint index; meta = GST_META_V4L2_GET (buf); g_assert (meta != NULL); index = meta->vbuffer.index; GST_LOG_OBJECT (pool, "enqueue buffer %p, index:%d, queued:%d", buf, index, pool->num_queued); if (pool->buffers[index] != NULL) goto already_queued; 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; 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; 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--; GST_LOG_OBJECT (pool, "dequeued buffer %p seq:%d (ix=%d), used %d, flags %08x, pool-queued=%d, buffer=%p", outbuf, vbuffer.sequence, vbuffer.index, vbuffer.bytesused, vbuffer.flags, 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_TFF); if (vbuffer.field == V4L2_FIELD_INTERLACED_BT) GST_BUFFER_FLAG_UNSET (outbuf, GST_VIDEO_BUFFER_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); *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, GstBufferPoolParams * params) { GstFlowReturn ret; GstV4l2BufferPool *pool = GST_V4L2_BUFFER_POOL (bpool); GstV4l2Object *obj = pool->obj; GST_DEBUG_OBJECT (pool, "acquire"); if (GST_BUFFER_POOL_IS_FLUSHING (bpool)) goto flushing; switch (obj->type) { case V4L2_BUF_TYPE_VIDEO_CAPTURE: /* capture, This function should return a buffer with new captured data */ switch (obj->mode) { case GST_V4L2_IO_RW: /* take empty buffer from the pool */ ret = GST_BUFFER_POOL_CLASS (parent_class)->acquire_buffer (bpool, buffer, params); break; case GST_V4L2_IO_MMAP: /* just dequeue a buffer, we basically use the queue of v4l2 as the * storage for our buffers. */ ret = gst_v4l2_buffer_pool_dqbuf (pool, buffer); break; case GST_V4L2_IO_USERPTR: default: g_assert_not_reached (); break; } break; case V4L2_BUF_TYPE_VIDEO_OUTPUT: /* playback, This function should return an empty buffer */ switch (obj->mode) { case GST_V4L2_IO_RW: /* get an empty buffer */ ret = GST_BUFFER_POOL_CLASS (parent_class)->acquire_buffer (bpool, buffer, params); break; case GST_V4L2_IO_MMAP: { GstBufferPoolParams tparams = { 0, }; if (params) tparams = *params; tparams.flags |= GST_BUFFER_POOL_FLAG_DONTWAIT; /* first try to 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); } break; } case GST_V4L2_IO_USERPTR: default: g_assert_not_reached (); break; } break; default: g_assert_not_reached (); break; } return ret; /* ERRORS */ flushing: { GST_DEBUG_OBJECT (pool, "We are flushing"); return GST_FLOW_WRONG_STATE; } } 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_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: { GstMetaV4l2 *meta; meta = GST_META_V4L2_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 { GST_LOG_OBJECT (pool, "buffer is queued"); } 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->buffers) { g_free (pool->buffers); pool->buffers = NULL; } 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 * @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 */ GstBufferPool * gst_v4l2_buffer_pool_new (GstV4l2Object * obj) { GstV4l2BufferPool *pool; 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; return GST_BUFFER_POOL_CAST (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; gpointer data; gint buffersize; buffersize = gst_buffer_get_size (buf); GST_LOG_OBJECT (pool, "reading %d bytes into buffer %p", buffersize, buf); data = gst_buffer_map (buf, NULL, NULL, GST_MAP_WRITE); do { if ((res = gst_v4l2_object_poll (obj)) != GST_FLOW_OK) goto poll_error; amount = v4l2_read (obj->video_fd, data, buffersize); if (amount == buffersize) { 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, data, 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'."), buffersize, obj->videodev), GST_ERROR_SYSTEM); res = GST_FLOW_ERROR; goto cleanup; } cleanup: { gst_buffer_unmap (buf, data, 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 (GstBufferPool * bpool, GstBuffer * buf) { GstFlowReturn ret = GST_FLOW_OK; GstV4l2BufferPool *pool = GST_V4L2_BUFFER_POOL (bpool); 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() */ break; case GST_V4L2_IO_MMAP: { GstBuffer *to_queue; if (buf->pool == bpool) { /* nothing, we can queue directly */ to_queue = buf; } else { 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; /* 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; break; } case GST_V4L2_IO_USERPTR: default: g_assert_not_reached (); break; } break; default: g_assert_not_reached (); break; } done: return ret; /* ERRORS */ 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_available_buffers: * @pool: the pool * * Check the number of buffers available to the driver, ie. buffers that * have been QBUF'd but not yet DQBUF'd. * * Returns: the number of buffers available. */ gint gst_v4l2_buffer_pool_available_buffers (GstBufferPool * bpool) { GstV4l2BufferPool *pool = GST_V4L2_BUFFER_POOL (bpool); return pool->num_queued; }