3 * Copyright (C) 2001-2002 Ronald Bultje <rbultje@ronald.bitfreak.net>
4 * 2006 Edgard Lima <edgard.lima@indt.org.br>
5 * 2009 Texas Instruments, Inc - http://www.ti.com/
7 * gstv4l2bufferpool.c V4L2 buffer pool class
9 * This library is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU Library General Public
11 * License as published by the Free Software Foundation; either
12 * version 2 of the License, or (at your option) any later version.
14 * This library is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 * Library General Public License for more details.
19 * You should have received a copy of the GNU Library General Public
20 * License along with this library; if not, write to the
21 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
22 * Boston, MA 02111-1307, USA.
33 #include "gst/video/video.h"
34 #include "gst/video/gstmetavideo.h"
36 #include <gstv4l2bufferpool.h>
38 #include "gstv4l2src.h"
39 #include "gstv4l2sink.h"
40 #include "v4l2_calls.h"
41 #include "gst/gst-i18n-plugin.h"
43 /* videodev2.h is not versioned and we can't easily check for the presence
44 * of enum values at compile time, but the V4L2_CAP_VIDEO_OUTPUT_OVERLAY define
45 * was added in the same commit as V4L2_FIELD_INTERLACED_{TB,BT} (b2787845) */
46 #ifndef V4L2_CAP_VIDEO_OUTPUT_OVERLAY
47 #define V4L2_FIELD_INTERLACED_TB 8
48 #define V4L2_FIELD_INTERLACED_BT 9
52 GST_DEBUG_CATEGORY_EXTERN (v4l2_debug);
53 #define GST_CAT_DEFAULT v4l2_debug
59 gst_meta_v4l2_get_info (void)
61 static const GstMetaInfo *meta_info = NULL;
63 if (meta_info == NULL) {
65 gst_meta_register ("GstMetaV4l2", "GstMetaV4l2",
66 sizeof (GstMetaV4l2), (GstMetaInitFunction) NULL,
67 (GstMetaFreeFunction) NULL, (GstMetaCopyFunction) NULL,
68 (GstMetaTransformFunction) NULL);
76 #define gst_v4l2_buffer_pool_parent_class parent_class
77 G_DEFINE_TYPE (GstV4l2BufferPool, gst_v4l2_buffer_pool, GST_TYPE_BUFFER_POOL);
79 static void gst_v4l2_buffer_pool_release_buffer (GstBufferPool * bpool,
83 gst_v4l2_buffer_pool_free_buffer (GstBufferPool * bpool, GstBuffer * buffer)
85 GstV4l2BufferPool *pool = GST_V4L2_BUFFER_POOL (bpool);
93 case GST_V4L2_IO_MMAP:
98 meta = GST_META_V4L2_GET (buffer);
99 g_assert (meta != NULL);
101 index = meta->vbuffer.index;
102 GST_LOG_OBJECT (pool,
103 "mmap buffer %p idx %d (data %p, len %u) freed, unmapping", buffer,
104 index, meta->mem, meta->vbuffer.length);
106 v4l2_munmap (meta->mem, meta->vbuffer.length);
107 pool->buffers[index] = NULL;
110 case GST_V4L2_IO_USERPTR:
112 g_assert_not_reached ();
115 gst_buffer_unref (buffer);
119 gst_v4l2_buffer_pool_alloc_buffer (GstBufferPool * bpool, GstBuffer ** buffer,
120 GstBufferPoolParams * params)
122 GstV4l2BufferPool *pool = GST_V4L2_BUFFER_POOL (bpool);
136 gst_buffer_new_allocate (pool->allocator, pool->size, pool->align);
139 case GST_V4L2_IO_MMAP:
141 newbuf = gst_buffer_new ();
142 meta = GST_META_V4L2_ADD (newbuf);
144 index = pool->num_allocated;
146 GST_LOG_OBJECT (pool, "creating buffer %u, %p", index, newbuf, pool);
148 meta->vbuffer.index = index;
149 meta->vbuffer.type = obj->type;
150 meta->vbuffer.memory = V4L2_MEMORY_MMAP;
152 if (v4l2_ioctl (pool->video_fd, VIDIOC_QUERYBUF, &meta->vbuffer) < 0)
153 goto querybuf_failed;
155 GST_LOG_OBJECT (pool, " index: %u", meta->vbuffer.index);
156 GST_LOG_OBJECT (pool, " type: %d", meta->vbuffer.type);
157 GST_LOG_OBJECT (pool, " bytesused: %u", meta->vbuffer.bytesused);
158 GST_LOG_OBJECT (pool, " flags: %08x", meta->vbuffer.flags);
159 GST_LOG_OBJECT (pool, " field: %d", meta->vbuffer.field);
160 GST_LOG_OBJECT (pool, " memory: %d", meta->vbuffer.memory);
161 if (meta->vbuffer.memory == V4L2_MEMORY_MMAP)
162 GST_LOG_OBJECT (pool, " MMAP offset: %u", meta->vbuffer.m.offset);
163 GST_LOG_OBJECT (pool, " length: %u", meta->vbuffer.length);
164 GST_LOG_OBJECT (pool, " input: %u", meta->vbuffer.input);
166 meta->mem = v4l2_mmap (0, meta->vbuffer.length,
167 PROT_READ | PROT_WRITE, MAP_SHARED, pool->video_fd,
168 meta->vbuffer.m.offset);
169 if (meta->mem == MAP_FAILED)
172 gst_buffer_take_memory (newbuf, -1,
173 gst_memory_new_wrapped (0,
174 meta->mem, NULL, meta->vbuffer.length, 0, meta->vbuffer.length));
176 /* add metadata to raw video buffers */
177 if (pool->add_videometa && info->finfo) {
178 gsize offset[GST_VIDEO_MAX_PLANES];
179 gint stride[GST_VIDEO_MAX_PLANES];
182 stride[0] = obj->bytesperline;
184 GST_DEBUG_OBJECT (pool, "adding video meta, stride %d", stride[0]);
185 gst_buffer_add_meta_video_full (newbuf, info->flags,
186 GST_VIDEO_INFO_FORMAT (info), GST_VIDEO_INFO_WIDTH (info),
187 GST_VIDEO_INFO_HEIGHT (info), GST_VIDEO_INFO_N_PLANES (info),
192 case GST_V4L2_IO_USERPTR:
194 g_assert_not_reached ();
198 pool->num_allocated++;
207 gint errnosave = errno;
209 GST_WARNING ("Failed QUERYBUF: %s", g_strerror (errnosave));
210 gst_buffer_unref (newbuf);
212 return GST_FLOW_ERROR;
216 gint errnosave = errno;
218 GST_WARNING ("Failed to mmap: %s", g_strerror (errnosave));
219 gst_buffer_unref (newbuf);
221 return GST_FLOW_ERROR;
226 gst_v4l2_buffer_pool_set_config (GstBufferPool * bpool, GstStructure * config)
228 GstV4l2BufferPool *pool = GST_V4L2_BUFFER_POOL (bpool);
229 GstV4l2Object *obj = pool->obj;
231 guint size, min_buffers, max_buffers;
234 GST_DEBUG_OBJECT (pool, "set config");
236 pool->add_videometa =
237 gst_buffer_pool_config_has_meta (config, GST_META_API_VIDEO);
239 if (!pool->add_videometa) {
242 /* we don't have video metadata, see if the strides are compatible */
243 stride = GST_VIDEO_INFO_PLANE_STRIDE (&obj->info, 0);
245 GST_DEBUG_OBJECT (pool, "no videometadata, checking strides %d and %u",
246 stride, obj->bytesperline);
248 if (stride != obj->bytesperline)
249 goto missing_video_api;
252 /* parse the config and keep around */
253 if (!gst_buffer_pool_config_get (config, &caps, &size, &min_buffers,
254 &max_buffers, &prefix, &align))
257 GST_DEBUG_OBJECT (pool, "config %" GST_PTR_FORMAT, config);
260 pool->max_buffers = MAX (min_buffers, max_buffers);
261 pool->min_buffers = MIN (pool->max_buffers, min_buffers);
262 pool->prefix = prefix;
265 gst_buffer_pool_config_set (config, caps, size, min_buffers,
266 max_buffers, prefix, align);
268 return GST_BUFFER_POOL_CLASS (parent_class)->set_config (bpool, config);
273 GST_ERROR_OBJECT (pool, "missing GstMetaVideo API in config, "
274 "default stride: %d, wanted stride %u",
275 GST_VIDEO_INFO_PLANE_STRIDE (&obj->info, 0), obj->bytesperline);
280 GST_ERROR_OBJECT (pool, "invalid config %" GST_PTR_FORMAT, config);
286 start_streaming (GstV4l2BufferPool * pool)
288 GstV4l2Object *obj = pool->obj;
293 case GST_V4L2_IO_MMAP:
294 case GST_V4L2_IO_USERPTR:
295 GST_DEBUG_OBJECT (pool, "STREAMON");
296 if (v4l2_ioctl (pool->video_fd, VIDIOC_STREAMON, &obj->type) < 0)
300 g_assert_not_reached ();
304 pool->streaming = TRUE;
311 GST_ERROR_OBJECT (pool, "error with STREAMON %d (%s)", errno,
318 gst_v4l2_buffer_pool_start (GstBufferPool * bpool)
320 GstV4l2BufferPool *pool = GST_V4L2_BUFFER_POOL (bpool);
321 GstV4l2Object *obj = pool->obj;
323 struct v4l2_requestbuffers breq;
324 gint min_buffers, max_buffers;
326 min_buffers = pool->min_buffers;
327 max_buffers = pool->max_buffers;
334 case GST_V4L2_IO_MMAP:
336 /* first, lets request buffers, and see how many we can get: */
337 GST_DEBUG_OBJECT (pool, "starting, requesting %d MMAP buffers",
340 memset (&breq, 0, sizeof (struct v4l2_requestbuffers));
341 breq.type = obj->type;
342 breq.count = max_buffers;
343 breq.memory = V4L2_MEMORY_MMAP;
345 if (v4l2_ioctl (pool->video_fd, VIDIOC_REQBUFS, &breq) < 0)
348 GST_LOG_OBJECT (pool, " count: %u", breq.count);
349 GST_LOG_OBJECT (pool, " type: %d", breq.type);
350 GST_LOG_OBJECT (pool, " memory: %d", breq.memory);
352 if (breq.count < GST_V4L2_MIN_BUFFERS)
355 if (max_buffers != breq.count) {
356 GST_WARNING_OBJECT (pool, "using %u buffers instead", breq.count);
357 max_buffers = breq.count;
361 case GST_V4L2_IO_USERPTR:
363 g_assert_not_reached ();
368 pool->max_buffers = max_buffers;
369 pool->buffers = g_new0 (GstBuffer *, max_buffers);
370 pool->num_allocated = 0;
372 /* now, allocate the buffers: */
373 for (n = 0; n < min_buffers; n++) {
376 if (gst_v4l2_buffer_pool_alloc_buffer (bpool, &buffer, NULL) != GST_FLOW_OK)
377 goto buffer_new_failed;
379 gst_v4l2_buffer_pool_release_buffer (bpool, buffer);
382 /* we can start capturing now, we wait for the playback case until we queued
383 * the first buffer */
384 if (obj->type == V4L2_BUF_TYPE_VIDEO_CAPTURE)
385 if (!start_streaming (pool))
388 gst_poll_set_flushing (obj->poll, FALSE);
395 GST_ERROR_OBJECT (pool,
396 "error requesting %d buffers: %s", max_buffers, g_strerror (errno));
401 GST_ERROR_OBJECT (pool,
402 "we received %d from device '%s', we want at least %d",
403 breq.count, obj->videodev, GST_V4L2_MIN_BUFFERS);
408 GST_ERROR_OBJECT (pool, "failed to create a buffer");
413 GST_ERROR_OBJECT (pool, "failed to start streaming");
419 gst_v4l2_buffer_pool_stop (GstBufferPool * bpool)
422 GstV4l2BufferPool *pool = GST_V4L2_BUFFER_POOL (bpool);
423 GstV4l2Object *obj = pool->obj;
426 GST_DEBUG_OBJECT (pool, "stopping pool");
428 gst_poll_set_flushing (obj->poll, TRUE);
430 if (pool->streaming) {
434 case GST_V4L2_IO_MMAP:
435 case GST_V4L2_IO_USERPTR:
436 /* we actually need to sync on all queued buffers but not
437 * on the non-queued ones */
438 GST_DEBUG_OBJECT (pool, "STREAMOFF");
439 if (v4l2_ioctl (pool->video_fd, VIDIOC_STREAMOFF, &obj->type) < 0)
443 g_assert_not_reached ();
446 pool->streaming = FALSE;
449 /* first free the buffers in the queue */
450 ret = GST_BUFFER_POOL_CLASS (parent_class)->stop (bpool);
452 /* then free the remaining buffers */
453 for (n = 0; n < pool->num_allocated; n++) {
454 if (pool->buffers[n])
455 gst_v4l2_buffer_pool_free_buffer (bpool, pool->buffers[n]);
462 GST_ERROR_OBJECT (pool, "error with STREAMOFF %d (%s)", errno,
469 gst_v4l2_object_poll (GstV4l2Object * v4l2object)
473 if (v4l2object->can_poll_device) {
474 GST_LOG_OBJECT (v4l2object->element, "polling device");
475 ret = gst_poll_wait (v4l2object->poll, GST_CLOCK_TIME_NONE);
476 if (G_UNLIKELY (ret < 0)) {
479 if (errno == ENXIO) {
480 GST_WARNING_OBJECT (v4l2object->element,
481 "v4l2 device doesn't support polling. Disabling");
482 v4l2object->can_poll_device = FALSE;
484 if (errno != EAGAIN && errno != EINTR)
494 GST_DEBUG ("stop called");
495 return GST_FLOW_WRONG_STATE;
499 GST_ELEMENT_ERROR (v4l2object->element, RESOURCE, READ, (NULL),
500 ("poll error %d: %s (%d)", ret, g_strerror (errno), errno));
501 return GST_FLOW_ERROR;
506 gst_v4l2_buffer_pool_qbuf (GstV4l2BufferPool * pool, GstBuffer * buf)
511 meta = GST_META_V4L2_GET (buf);
512 g_assert (meta != NULL);
514 index = meta->vbuffer.index;
516 GST_LOG_OBJECT (pool, "enqueue buffer %p, index:%d, queued:%d", buf,
517 index, pool->num_queued);
519 if (pool->buffers[index] != NULL)
522 if (v4l2_ioctl (pool->video_fd, VIDIOC_QBUF, &meta->vbuffer) < 0)
525 pool->buffers[index] = buf;
533 GST_WARNING_OBJECT (pool, "the buffer was already queued");
534 return GST_FLOW_ERROR;
538 GST_WARNING_OBJECT (pool, "could not queue a buffer %d (%s)", errno,
540 return GST_FLOW_ERROR;
545 gst_v4l2_buffer_pool_dqbuf (GstV4l2BufferPool * pool, GstBuffer ** buffer)
549 struct v4l2_buffer vbuffer;
550 GstV4l2Object *obj = pool->obj;
552 if (obj->type == V4L2_BUF_TYPE_VIDEO_CAPTURE) {
553 /* select works for input devices when data is available. According to the
554 * specs we can also poll to find out when a frame has been displayed but
555 * that just seems to lock up here */
556 if ((res = gst_v4l2_object_poll (obj)) != GST_FLOW_OK)
560 memset (&vbuffer, 0x00, sizeof (vbuffer));
561 vbuffer.type = obj->type;
562 vbuffer.memory = V4L2_MEMORY_MMAP;
564 GST_LOG_OBJECT (pool, "doing DQBUF");
565 if (v4l2_ioctl (pool->video_fd, VIDIOC_DQBUF, &vbuffer) < 0)
568 /* get our GstBuffer with that index from the pool, if the buffer was
569 * outstanding we have a serious problem.
571 outbuf = pool->buffers[vbuffer.index];
575 /* mark the buffer outstanding */
576 pool->buffers[vbuffer.index] = NULL;
579 GST_LOG_OBJECT (pool,
580 "dequeued buffer %p seq:%d (ix=%d), used %d, flags %08x, pool-queued=%d, buffer=%p",
581 outbuf, vbuffer.sequence, vbuffer.index, vbuffer.bytesused, vbuffer.flags,
582 pool->num_queued, outbuf);
584 /* set top/bottom field first if v4l2_buffer has the information */
585 if (vbuffer.field == V4L2_FIELD_INTERLACED_TB)
586 GST_BUFFER_FLAG_SET (outbuf, GST_VIDEO_BUFFER_TFF);
587 if (vbuffer.field == V4L2_FIELD_INTERLACED_BT)
588 GST_BUFFER_FLAG_UNSET (outbuf, GST_VIDEO_BUFFER_TFF);
590 /* this can change at every frame, esp. with jpeg */
591 if (obj->type == V4L2_BUF_TYPE_VIDEO_CAPTURE)
592 gst_buffer_resize (outbuf, 0, vbuffer.bytesused);
594 gst_buffer_resize (outbuf, 0, vbuffer.length);
603 GST_DEBUG_OBJECT (pool, "poll error %s", gst_flow_get_name (res));
608 GST_WARNING_OBJECT (pool,
609 "problem dequeuing frame %d (ix=%d), pool-ct=%d, buf.flags=%d",
610 vbuffer.sequence, vbuffer.index,
611 GST_MINI_OBJECT_REFCOUNT (pool), vbuffer.flags);
615 GST_WARNING_OBJECT (pool,
616 "Non-blocking I/O has been selected using O_NONBLOCK and"
617 " no buffer was in the outgoing queue. device %s", obj->videodev);
620 GST_ERROR_OBJECT (pool,
621 "The buffer type is not supported, or the index is out of bounds, "
622 "or no buffers have been allocated yet, or the userptr "
623 "or length are invalid. device %s", obj->videodev);
626 GST_ERROR_OBJECT (pool,
627 "insufficient memory to enqueue a user pointer buffer");
630 GST_INFO_OBJECT (pool,
631 "VIDIOC_DQBUF failed due to an internal error."
632 " Can also indicate temporary problems like signal loss."
633 " Note the driver might dequeue an (empty) buffer despite"
634 " returning an error, or even stop capturing."
635 " device %s", obj->videodev);
636 /* have we de-queued a buffer ? */
637 if (!(vbuffer.flags & (V4L2_BUF_FLAG_QUEUED | V4L2_BUF_FLAG_DONE))) {
638 GST_DEBUG_OBJECT (pool, "reenqueing buffer");
639 /* FIXME ... should we do something here? */
643 GST_WARNING_OBJECT (pool,
644 "could not sync on a buffer on device %s", obj->videodev);
647 GST_WARNING_OBJECT (pool,
648 "Grabbing frame got interrupted on %s unexpectedly. %d: %s.",
649 obj->videodev, errno, g_strerror (errno));
652 return GST_FLOW_ERROR;
656 GST_ERROR_OBJECT (pool, "No free buffer found in the pool at index %d.",
658 return GST_FLOW_ERROR;
663 gst_v4l2_buffer_pool_acquire_buffer (GstBufferPool * bpool, GstBuffer ** buffer,
664 GstBufferPoolParams * params)
667 GstV4l2BufferPool *pool = GST_V4L2_BUFFER_POOL (bpool);
668 GstV4l2Object *obj = pool->obj;
670 GST_DEBUG_OBJECT (pool, "acquire");
672 if (GST_BUFFER_POOL_IS_FLUSHING (bpool))
676 case V4L2_BUF_TYPE_VIDEO_CAPTURE:
677 /* capture, This function should return a buffer with new captured data */
680 /* take empty buffer from the pool */
681 ret = GST_BUFFER_POOL_CLASS (parent_class)->acquire_buffer (bpool,
685 case GST_V4L2_IO_MMAP:
686 /* just dequeue a buffer, we basically use the queue of v4l2 as the
687 * storage for our buffers. This function does poll first so we can
688 * interrupt it fine. */
689 ret = gst_v4l2_buffer_pool_dqbuf (pool, buffer);
692 case GST_V4L2_IO_USERPTR:
694 g_assert_not_reached ();
699 case V4L2_BUF_TYPE_VIDEO_OUTPUT:
700 /* playback, This function should return an empty buffer */
703 /* get an empty buffer */
704 ret = GST_BUFFER_POOL_CLASS (parent_class)->acquire_buffer (bpool,
708 case GST_V4L2_IO_MMAP:
709 /* get a free unqueued buffer */
710 ret = GST_BUFFER_POOL_CLASS (parent_class)->acquire_buffer (bpool,
714 case GST_V4L2_IO_USERPTR:
716 g_assert_not_reached ();
722 g_assert_not_reached ();
730 GST_DEBUG_OBJECT (pool, "We are flushing");
731 return GST_FLOW_WRONG_STATE;
736 gst_v4l2_buffer_pool_release_buffer (GstBufferPool * bpool, GstBuffer * buffer)
738 GstV4l2BufferPool *pool = GST_V4L2_BUFFER_POOL (bpool);
739 GstV4l2Object *obj = pool->obj;
741 GST_DEBUG_OBJECT (pool, "release buffer %p", buffer);
744 case V4L2_BUF_TYPE_VIDEO_CAPTURE:
745 /* capture, put the buffer back in the queue so that we can refill it
749 /* release back in the pool */
750 GST_BUFFER_POOL_CLASS (parent_class)->release_buffer (bpool, buffer);
753 case GST_V4L2_IO_MMAP:
754 /* queue back in the device */
755 gst_v4l2_buffer_pool_qbuf (pool, buffer);
758 case GST_V4L2_IO_USERPTR:
760 g_assert_not_reached ();
765 case V4L2_BUF_TYPE_VIDEO_OUTPUT:
768 /* release back in the pool */
769 GST_BUFFER_POOL_CLASS (parent_class)->release_buffer (bpool, buffer);
772 case GST_V4L2_IO_MMAP:
776 meta = GST_META_V4L2_GET (buffer);
777 g_assert (meta != NULL);
779 if (pool->buffers[meta->vbuffer.index] == NULL) {
780 GST_LOG_OBJECT (pool, "buffer not queued, putting on free list");
781 /* playback, put the buffer back in the queue to refill later. */
782 GST_BUFFER_POOL_CLASS (parent_class)->release_buffer (bpool,
785 /* the buffer is queued in the device but maybe not played yet. We just
786 * leave it there and not make it available for future calls to acquire
787 * for now. The buffer will be dequeued and reused later. */
788 GST_LOG_OBJECT (pool, "buffer is queued");
793 case GST_V4L2_IO_USERPTR:
795 g_assert_not_reached ();
801 g_assert_not_reached ();
807 gst_v4l2_buffer_pool_finalize (GObject * object)
809 GstV4l2BufferPool *pool = GST_V4L2_BUFFER_POOL (object);
811 if (pool->video_fd >= 0)
812 v4l2_close (pool->video_fd);
815 g_free (pool->buffers);
816 pool->buffers = NULL;
819 G_OBJECT_CLASS (parent_class)->finalize (object);
823 gst_v4l2_buffer_pool_init (GstV4l2BufferPool * pool)
828 gst_v4l2_buffer_pool_class_init (GstV4l2BufferPoolClass * klass)
830 GObjectClass *object_class = G_OBJECT_CLASS (klass);
831 GstBufferPoolClass *bufferpool_class = GST_BUFFER_POOL_CLASS (klass);
833 object_class->finalize = gst_v4l2_buffer_pool_finalize;
835 bufferpool_class->start = gst_v4l2_buffer_pool_start;
836 bufferpool_class->stop = gst_v4l2_buffer_pool_stop;
837 bufferpool_class->set_config = gst_v4l2_buffer_pool_set_config;
838 bufferpool_class->alloc_buffer = gst_v4l2_buffer_pool_alloc_buffer;
839 bufferpool_class->acquire_buffer = gst_v4l2_buffer_pool_acquire_buffer;
840 bufferpool_class->release_buffer = gst_v4l2_buffer_pool_release_buffer;
841 bufferpool_class->free_buffer = gst_v4l2_buffer_pool_free_buffer;
845 * gst_v4l2_buffer_pool_new:
846 * @obj: the v4l2 object owning the pool
848 * Construct a new buffer pool.
850 * Returns: the new pool, use gst_object_unref() to free resources
853 gst_v4l2_buffer_pool_new (GstV4l2Object * obj)
855 GstV4l2BufferPool *pool;
858 fd = v4l2_dup (obj->video_fd);
862 pool = (GstV4l2BufferPool *) g_object_new (GST_TYPE_V4L2_BUFFER_POOL, NULL);
871 GST_DEBUG ("failed to dup fd %d (%s)", errno, g_strerror (errno));
877 gst_v4l2_do_read (GstV4l2BufferPool * pool, GstBuffer * buf)
880 GstV4l2Object *obj = pool->obj;
885 toread = obj->sizeimage;
887 GST_LOG_OBJECT (pool, "reading %d bytes into buffer %p", toread, buf);
889 data = gst_buffer_map (buf, NULL, NULL, GST_MAP_WRITE);
892 if ((res = gst_v4l2_object_poll (obj)) != GST_FLOW_OK)
895 amount = v4l2_read (obj->video_fd, data, toread);
897 if (amount == toread) {
899 } else if (amount == -1) {
900 if (errno == EAGAIN || errno == EINTR) {
905 /* short reads can happen if a signal interrupts the read */
910 GST_LOG_OBJECT (pool, "read %d bytes", amount);
911 gst_buffer_unmap (buf, data, amount);
918 GST_DEBUG ("poll error %s", gst_flow_get_name (res));
923 GST_ELEMENT_ERROR (obj->element, RESOURCE, READ,
924 (_("Error reading %d bytes from device '%s'."),
925 toread, obj->videodev), GST_ERROR_SYSTEM);
926 res = GST_FLOW_ERROR;
931 gst_buffer_unmap (buf, data, 0);
937 * gst_v4l2_buffer_pool_process:
938 * @bpool: a #GstBufferPool
941 * Process @buf in @bpool. For capture devices, this functions fills @buf with
942 * data from the device. For output devices, this functions send the contents of
943 * @buf to the device for playback.
945 * Returns: %GST_FLOW_OK on success.
948 gst_v4l2_buffer_pool_process (GstV4l2BufferPool * pool, GstBuffer * buf)
950 GstFlowReturn ret = GST_FLOW_OK;
951 GstBufferPool *bpool = GST_BUFFER_POOL_CAST (pool);
952 GstV4l2Object *obj = pool->obj;
954 GST_DEBUG_OBJECT (pool, "process buffer %p", buf);
957 case V4L2_BUF_TYPE_VIDEO_CAPTURE:
961 /* capture into the buffer */
962 ret = gst_v4l2_do_read (pool, buf);
965 case GST_V4L2_IO_MMAP:
969 if (buf->pool == bpool)
970 /* nothing, data was inside the buffer when we did _acquire() */
973 /* buffer not from our pool, grab a frame and copy it into the target */
974 if ((ret = gst_v4l2_buffer_pool_dqbuf (pool, &tmp)) != GST_FLOW_OK)
977 if (!gst_v4l2_object_copy (obj, buf, tmp))
980 /* an queue the buffer again after the copy */
981 if ((ret = gst_v4l2_buffer_pool_qbuf (pool, tmp)) != GST_FLOW_OK)
986 case GST_V4L2_IO_USERPTR:
988 g_assert_not_reached ();
993 case V4L2_BUF_TYPE_VIDEO_OUTPUT:
997 /* FIXME, do write() */
998 GST_WARNING_OBJECT (pool, "implement write()");
1001 case GST_V4L2_IO_MMAP:
1003 GstBuffer *to_queue;
1005 if (buf->pool == bpool) {
1006 /* nothing, we can queue directly */
1009 /* this can block if all buffers are outstanding which would be
1010 * strange because we would expect the upstream element to have
1011 * allocated them and returned to us.. */
1012 ret = GST_BUFFER_POOL_CLASS (parent_class)->acquire_buffer (bpool,
1014 if (ret != GST_FLOW_OK)
1017 /* copy into it and queue */
1018 if (!gst_v4l2_object_copy (obj, to_queue, buf))
1022 if ((ret = gst_v4l2_buffer_pool_qbuf (pool, to_queue)) != GST_FLOW_OK)
1025 /* if we are not streaming yet (this is the first buffer, start
1027 if (!pool->streaming)
1028 if (!start_streaming (pool))
1031 if (pool->num_queued == pool->num_allocated) {
1032 /* all buffers are queued, try to dequeue one and release it back
1033 * into the pool so that _acquire can get to it again. */
1034 ret = gst_v4l2_buffer_pool_dqbuf (pool, &to_queue);
1035 if (ret != GST_FLOW_OK)
1038 /* release the rendered buffer back into the pool. This wakes up any
1039 * thread waiting for a buffer in _acquire() */
1040 gst_v4l2_buffer_pool_release_buffer (bpool, to_queue);
1045 case GST_V4L2_IO_USERPTR:
1047 g_assert_not_reached ();
1052 g_assert_not_reached ();
1061 GST_ERROR_OBJECT (obj->element, "failed to copy data");
1062 return GST_FLOW_ERROR;
1066 GST_ERROR_OBJECT (obj->element, "failed to start streaming");
1067 return GST_FLOW_ERROR;