3 * Copyright (C) 2001-2002 Ronald Bultje <rbultje@ronald.bitfreak.net>
4 * 2006 Edgard Lima <edgard.lima@gmail.com>
6 * gstv4l2src.c: Video4Linux2 source element
8 * This library is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Library General Public
10 * License as published by the Free Software Foundation; either
11 * version 2 of the License, or (at your option) any later version.
13 * This library is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Library General Public License for more details.
18 * You should have received a copy of the GNU Library General Public
19 * License along with this library; if not, write to the
20 * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
21 * Boston, MA 02110-1301, USA.
25 * SECTION:element-v4l2src
27 * v4l2src can be used to capture video from v4l2 devices, like webcams and tv
31 * <title>Example launch lines</title>
33 * gst-launch-1.0 v4l2src ! xvimagesink
34 * ]| This pipeline shows the video captured from /dev/video0 tv card and for
37 * gst-launch-1.0 v4l2src ! jpegdec ! xvimagesink
38 * ]| This pipeline shows the video captured from a webcam that delivers jpeg
42 * Since 1.14, the use of libv4l2 has been disabled due to major bugs in the
43 * emulation layer. To enable usage of this library, set the environment
44 * variable GST_V4L2_USE_LIBV4L2=1.
55 #include <gst/video/gstvideometa.h>
56 #include <gst/video/gstvideopool.h>
58 #include "gstv4l2src.h"
60 #include "gstv4l2colorbalance.h"
61 #include "gstv4l2tuner.h"
62 #include "gstv4l2vidorient.h"
64 #include "gst/gst-i18n-plugin.h"
66 GST_DEBUG_CATEGORY (v4l2src_debug);
67 #define GST_CAT_DEFAULT v4l2src_debug
69 #define DEFAULT_PROP_DEVICE "/dev/video0"
74 V4L2_STD_OBJECT_PROPS,
75 #ifdef TIZEN_FEATURE_V4L2SRC_SUPPORT_CAMERA_ID
77 #endif /* TIZEN_FEATURE_V4L2SRC_SUPPORT_CAMERA_ID */
81 /* signals and args */
84 SIGNAL_PRE_SET_FORMAT,
88 static guint gst_v4l2_signals[LAST_SIGNAL] = { 0 };
90 GST_IMPLEMENT_V4L2_COLOR_BALANCE_METHODS (GstV4l2Src, gst_v4l2src);
91 GST_IMPLEMENT_V4L2_TUNER_METHODS (GstV4l2Src, gst_v4l2src);
92 GST_IMPLEMENT_V4L2_VIDORIENT_METHODS (GstV4l2Src, gst_v4l2src);
94 static void gst_v4l2src_uri_handler_init (gpointer g_iface,
97 #define gst_v4l2src_parent_class parent_class
98 G_DEFINE_TYPE_WITH_CODE (GstV4l2Src, gst_v4l2src, GST_TYPE_PUSH_SRC,
99 G_IMPLEMENT_INTERFACE (GST_TYPE_URI_HANDLER, gst_v4l2src_uri_handler_init);
100 G_IMPLEMENT_INTERFACE (GST_TYPE_TUNER, gst_v4l2src_tuner_interface_init);
101 G_IMPLEMENT_INTERFACE (GST_TYPE_COLOR_BALANCE,
102 gst_v4l2src_color_balance_interface_init);
103 G_IMPLEMENT_INTERFACE (GST_TYPE_VIDEO_ORIENTATION,
104 gst_v4l2src_video_orientation_interface_init));
106 static void gst_v4l2src_finalize (GstV4l2Src * v4l2src);
108 /* element methods */
109 static GstStateChangeReturn gst_v4l2src_change_state (GstElement * element,
110 GstStateChange transition);
112 /* basesrc methods */
113 static gboolean gst_v4l2src_start (GstBaseSrc * src);
114 static gboolean gst_v4l2src_unlock (GstBaseSrc * src);
115 static gboolean gst_v4l2src_unlock_stop (GstBaseSrc * src);
116 static gboolean gst_v4l2src_stop (GstBaseSrc * src);
117 static GstCaps *gst_v4l2src_get_caps (GstBaseSrc * src, GstCaps * filter);
118 static gboolean gst_v4l2src_query (GstBaseSrc * bsrc, GstQuery * query);
119 static gboolean gst_v4l2src_decide_allocation (GstBaseSrc * src,
121 static GstFlowReturn gst_v4l2src_create (GstPushSrc * src, GstBuffer ** out);
122 static GstCaps *gst_v4l2src_fixate (GstBaseSrc * basesrc, GstCaps * caps,
123 GstStructure * pref_s);
124 static gboolean gst_v4l2src_negotiate (GstBaseSrc * basesrc);
126 static void gst_v4l2src_set_property (GObject * object, guint prop_id,
127 const GValue * value, GParamSpec * pspec);
128 static void gst_v4l2src_get_property (GObject * object, guint prop_id,
129 GValue * value, GParamSpec * pspec);
132 gst_v4l2src_class_init (GstV4l2SrcClass * klass)
134 GObjectClass *gobject_class;
135 GstElementClass *element_class;
136 GstBaseSrcClass *basesrc_class;
137 GstPushSrcClass *pushsrc_class;
139 gobject_class = G_OBJECT_CLASS (klass);
140 element_class = GST_ELEMENT_CLASS (klass);
141 basesrc_class = GST_BASE_SRC_CLASS (klass);
142 pushsrc_class = GST_PUSH_SRC_CLASS (klass);
144 gobject_class->finalize = (GObjectFinalizeFunc) gst_v4l2src_finalize;
145 gobject_class->set_property = gst_v4l2src_set_property;
146 gobject_class->get_property = gst_v4l2src_get_property;
148 element_class->change_state = gst_v4l2src_change_state;
150 gst_v4l2_object_install_properties_helper (gobject_class,
151 DEFAULT_PROP_DEVICE);
153 #ifdef TIZEN_FEATURE_V4L2SRC_SUPPORT_CAMERA_ID
155 * GstV4l2Src:camera-id:
157 * The value which is set by application will be used as a number of device node.
158 * ex) 1 -> /dev/video1
160 g_object_class_install_property (gobject_class, PROP_CAMERA_ID,
161 g_param_spec_uint ("camera-id", "Camera ID",
162 "Camera ID for device node", 0, G_MAXUINT, 0,
163 G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
164 #endif /* TIZEN_FEATURE_V4L2SRC_SUPPORT_CAMERA_ID */
167 * GstV4l2Src::prepare-format:
168 * @v4l2src: the v4l2src instance
169 * @fd: the file descriptor of the current device
170 * @caps: the caps of the format being set
172 * This signal gets emitted before calling the v4l2 VIDIOC_S_FMT ioctl
173 * (set format). This allows for any custom configuration of the device to
174 * happen prior to the format being set.
175 * This is mostly useful for UVC H264 encoding cameras which need the H264
176 * Probe & Commit to happen prior to the normal Probe & Commit.
178 gst_v4l2_signals[SIGNAL_PRE_SET_FORMAT] = g_signal_new ("prepare-format",
179 G_TYPE_FROM_CLASS (klass),
181 0, NULL, NULL, NULL, G_TYPE_NONE, 2, G_TYPE_INT, GST_TYPE_CAPS);
183 gst_element_class_set_static_metadata (element_class,
184 "Video (video4linux2) Source", "Source/Video",
185 "Reads frames from a Video4Linux2 device",
186 "Edgard Lima <edgard.lima@gmail.com>, "
187 "Stefan Kost <ensonic@users.sf.net>");
189 gst_element_class_add_pad_template
191 gst_pad_template_new ("src", GST_PAD_SRC, GST_PAD_ALWAYS,
192 gst_v4l2_object_get_all_caps ()));
194 basesrc_class->get_caps = GST_DEBUG_FUNCPTR (gst_v4l2src_get_caps);
195 basesrc_class->start = GST_DEBUG_FUNCPTR (gst_v4l2src_start);
196 basesrc_class->unlock = GST_DEBUG_FUNCPTR (gst_v4l2src_unlock);
197 basesrc_class->unlock_stop = GST_DEBUG_FUNCPTR (gst_v4l2src_unlock_stop);
198 basesrc_class->stop = GST_DEBUG_FUNCPTR (gst_v4l2src_stop);
199 basesrc_class->query = GST_DEBUG_FUNCPTR (gst_v4l2src_query);
200 basesrc_class->negotiate = GST_DEBUG_FUNCPTR (gst_v4l2src_negotiate);
201 basesrc_class->decide_allocation =
202 GST_DEBUG_FUNCPTR (gst_v4l2src_decide_allocation);
204 pushsrc_class->create = GST_DEBUG_FUNCPTR (gst_v4l2src_create);
206 klass->v4l2_class_devices = NULL;
208 GST_DEBUG_CATEGORY_INIT (v4l2src_debug, "v4l2src", 0, "V4L2 source element");
212 gst_v4l2src_init (GstV4l2Src * v4l2src)
214 /* fixme: give an update_fps_function */
215 v4l2src->v4l2object = gst_v4l2_object_new (GST_ELEMENT (v4l2src),
216 GST_OBJECT (GST_BASE_SRC_PAD (v4l2src)), V4L2_BUF_TYPE_VIDEO_CAPTURE,
217 DEFAULT_PROP_DEVICE, gst_v4l2_get_input, gst_v4l2_set_input, NULL);
219 /* Avoid the slow probes */
220 v4l2src->v4l2object->skip_try_fmt_probes = TRUE;
222 gst_base_src_set_format (GST_BASE_SRC (v4l2src), GST_FORMAT_TIME);
223 gst_base_src_set_live (GST_BASE_SRC (v4l2src), TRUE);
228 gst_v4l2src_finalize (GstV4l2Src * v4l2src)
230 gst_v4l2_object_destroy (v4l2src->v4l2object);
232 G_OBJECT_CLASS (parent_class)->finalize ((GObject *) (v4l2src));
237 gst_v4l2src_set_property (GObject * object,
238 guint prop_id, const GValue * value, GParamSpec * pspec)
240 GstV4l2Src *v4l2src = GST_V4L2SRC (object);
242 if (!gst_v4l2_object_set_property_helper (v4l2src->v4l2object,
243 prop_id, value, pspec)) {
245 #ifdef TIZEN_FEATURE_V4L2SRC_SUPPORT_CAMERA_ID
247 g_free (v4l2src->v4l2object->videodev);
249 v4l2src->camera_id = g_value_get_uint (value);
250 v4l2src->v4l2object->videodev = g_strdup_printf ("/dev/video%u", v4l2src->camera_id);
252 GST_INFO_OBJECT(v4l2src, "videodev [%s]", v4l2src->v4l2object->videodev);
254 #endif /* TIZEN_FEATURE_V4L2SRC_SUPPORT_CAMERA_ID */
256 G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
263 gst_v4l2src_get_property (GObject * object,
264 guint prop_id, GValue * value, GParamSpec * pspec)
266 GstV4l2Src *v4l2src = GST_V4L2SRC (object);
268 if (!gst_v4l2_object_get_property_helper (v4l2src->v4l2object,
269 prop_id, value, pspec)) {
271 #ifdef TIZEN_FEATURE_V4L2SRC_SUPPORT_CAMERA_ID
273 g_value_set_uint (value, v4l2src->camera_id);
275 #endif /* TIZEN_FEATURE_V4L2SRC_SUPPORT_CAMERA_ID */
277 G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
283 struct PreferedCapsInfo
292 gst_vl42_src_fixate_fields (GQuark field_id, GValue * value, gpointer user_data)
294 GstStructure *s = user_data;
296 if (field_id == g_quark_from_string ("interlace-mode"))
299 if (field_id == g_quark_from_string ("colorimetry"))
302 gst_structure_fixate_field (s, g_quark_to_string (field_id));
308 gst_v4l2_src_fixate_struct_with_preference (GstStructure * s,
309 struct PreferedCapsInfo *pref)
311 if (gst_structure_has_field (s, "width"))
312 gst_structure_fixate_field_nearest_int (s, "width", pref->width);
314 if (gst_structure_has_field (s, "height"))
315 gst_structure_fixate_field_nearest_int (s, "height", pref->height);
317 if (gst_structure_has_field (s, "framerate"))
318 gst_structure_fixate_field_nearest_fraction (s, "framerate", pref->fps_n,
321 /* Finally, fixate everything else except the interlace-mode and colorimetry
322 * which still need further negotiation as it wasn't probed */
323 gst_structure_map_in_place (s, gst_vl42_src_fixate_fields, s);
327 gst_v4l2_src_parse_fixed_struct (GstStructure * s,
328 gint * width, gint * height, gint * fps_n, gint * fps_d)
330 if (gst_structure_has_field (s, "width") && width)
331 gst_structure_get_int (s, "width", width);
333 if (gst_structure_has_field (s, "height") && height)
334 gst_structure_get_int (s, "height", height);
336 if (gst_structure_has_field (s, "framerate") && fps_n && fps_d)
337 gst_structure_get_fraction (s, "framerate", fps_n, fps_d);
340 /* TODO Consider framerate */
342 gst_v4l2src_fixed_caps_compare (GstCaps * caps_a, GstCaps * caps_b,
343 struct PreferedCapsInfo *pref)
346 gint aw = G_MAXINT, ah = G_MAXINT, ad = G_MAXINT;
347 gint bw = G_MAXINT, bh = G_MAXINT, bd = G_MAXINT;
350 a = gst_caps_get_structure (caps_a, 0);
351 b = gst_caps_get_structure (caps_b, 0);
353 gst_v4l2_src_parse_fixed_struct (a, &aw, &ah, NULL, NULL);
354 gst_v4l2_src_parse_fixed_struct (b, &bw, &bh, NULL, NULL);
356 /* When both are smaller then pref, just append to the end */
357 if ((bw < pref->width || bh < pref->height)
358 && (aw < pref->width || ah < pref->height)) {
363 /* If a is smaller then pref and not b, then a goes after b */
364 if (aw < pref->width || ah < pref->height) {
369 /* If b is smaller then pref and not a, then a goes before b */
370 if (bw < pref->width || bh < pref->height) {
375 /* Both are larger or equal to the preference, prefer the smallest */
376 ad = MAX (1, aw - pref->width) * MAX (1, ah - pref->height);
377 bd = MAX (1, bw - pref->width) * MAX (1, bh - pref->height);
379 /* Adjust slightly in case width/height matched the preference */
380 if (aw == pref->width)
383 if (ah == pref->height)
386 if (bw == pref->width)
389 if (bh == pref->height)
392 /* If the choices are equivalent, maintain the order */
399 GST_TRACE ("Placing %ix%i (%s) %s %ix%i (%s)", aw, ah,
400 gst_structure_get_string (a, "format"), ret > 0 ? "after" : "before", bw,
401 bh, gst_structure_get_string (b, "format"));
406 gst_v4l2src_set_format (GstV4l2Src * v4l2src, GstCaps * caps,
407 GstV4l2Error * error)
411 obj = v4l2src->v4l2object;
413 /* make sure we stop capturing and dealloc buffers */
414 if (!gst_v4l2_object_stop (obj))
417 g_signal_emit (v4l2src, gst_v4l2_signals[SIGNAL_PRE_SET_FORMAT], 0,
418 v4l2src->v4l2object->video_fd, caps);
420 return gst_v4l2_object_set_format (obj, caps, error);
424 gst_v4l2src_fixate (GstBaseSrc * basesrc, GstCaps * caps, GstStructure * pref_s)
426 /* Let's prefer a good resolutiion as of today's standard. */
427 struct PreferedCapsInfo pref = {
430 GstV4l2Src *v4l2src = GST_V4L2SRC (basesrc);
431 GstV4l2Object *obj = v4l2src->v4l2object;
432 GList *caps_list = NULL;
435 GstV4l2Error error = GST_V4L2_ERROR_INIT;
436 GstCaps *fcaps = NULL;
438 GST_DEBUG_OBJECT (basesrc, "fixating caps %" GST_PTR_FORMAT, caps);
440 /* We consider the first structure from peercaps to be a preference. This is
441 * useful for matching a reported native display, or simply to avoid
442 * transformation to happen downstream. */
444 pref_s = gst_structure_copy (pref_s);
445 gst_v4l2_src_fixate_struct_with_preference (pref_s, &pref);
446 gst_v4l2_src_parse_fixed_struct (pref_s, &pref.width, &pref.height,
447 &pref.fps_n, &pref.fps_d);
448 gst_structure_free (pref_s);
451 GST_DEBUG_OBJECT (basesrc, "Prefered size %ix%i", pref.width, pref.height);
453 /* Sort the structures to get the caps that is nearest to our preferences,
454 * first. Use single struct caps for sorting so we preserve the features. */
455 for (i = 0; i < gst_caps_get_size (caps); i++) {
456 GstCaps *tmp = gst_caps_copy_nth (caps, i);
458 s = gst_caps_get_structure (tmp, 0);
459 gst_v4l2_src_fixate_struct_with_preference (s, &pref);
461 caps_list = g_list_insert_sorted_with_data (caps_list, tmp,
462 (GCompareDataFunc) gst_v4l2src_fixed_caps_compare, &pref);
465 gst_caps_unref (caps);
466 caps = gst_caps_new_empty ();
469 GstCaps *tmp = caps_list->data;
470 caps_list = g_list_delete_link (caps_list, caps_list);
471 gst_caps_append (caps, tmp);
474 GST_DEBUG_OBJECT (basesrc, "sorted and normalized caps %" GST_PTR_FORMAT,
477 /* Each structure in the caps has been fixated, except for the
478 * interlace-mode and colorimetry. Now normalize the caps so we can
479 * enumerate the possibilities */
480 caps = gst_caps_normalize (caps);
482 for (i = 0; i < gst_caps_get_size (caps); ++i) {
483 gst_v4l2_clear_error (&error);
485 gst_caps_unref (fcaps);
487 fcaps = gst_caps_copy_nth (caps, i);
489 /* try hard to avoid TRY_FMT since some UVC camera just crash when this
490 * is called at run-time. */
491 if (gst_v4l2_object_caps_is_subset (obj, fcaps)) {
492 gst_caps_unref (fcaps);
493 fcaps = gst_v4l2_object_get_current_caps (obj);
497 /* Just check if the format is acceptable, once we know
498 * no buffers should be outstanding we try S_FMT.
500 * Basesrc will do an allocation query that
501 * should indirectly reclaim buffers, after that we can
502 * set the format and then configure our pool */
503 if (gst_v4l2_object_try_format (obj, fcaps, &error)) {
504 /* make sure the caps changed before doing anything */
505 if (gst_v4l2_object_caps_equal (obj, fcaps))
508 v4l2src->renegotiation_adjust = v4l2src->offset + 1;
509 v4l2src->pending_set_fmt = TRUE;
513 /* Only EIVAL make sense, report any other errors, this way we don't keep
514 * probing if the device got disconnected, or if it's firmware stopped
516 if (error.error->code != GST_RESOURCE_ERROR_SETTINGS) {
522 if (i >= gst_caps_get_size (caps)) {
523 gst_v4l2_error (v4l2src, &error);
525 gst_caps_unref (fcaps);
526 gst_caps_unref (caps);
530 gst_caps_unref (caps);
532 GST_DEBUG_OBJECT (basesrc, "fixated caps %" GST_PTR_FORMAT, fcaps);
538 gst_v4l2src_negotiate (GstBaseSrc * basesrc)
541 GstCaps *caps = NULL;
542 GstCaps *peercaps = NULL;
543 gboolean result = FALSE;
545 /* first see what is possible on our source pad */
546 thiscaps = gst_pad_query_caps (GST_BASE_SRC_PAD (basesrc), NULL);
547 GST_DEBUG_OBJECT (basesrc, "caps of src: %" GST_PTR_FORMAT, thiscaps);
549 /* nothing or anything is allowed, we're done */
550 if (thiscaps == NULL || gst_caps_is_any (thiscaps))
553 /* get the peer caps without a filter as we'll filter ourselves later on */
554 peercaps = gst_pad_peer_query_caps (GST_BASE_SRC_PAD (basesrc), NULL);
555 GST_DEBUG_OBJECT (basesrc, "caps of peer: %" GST_PTR_FORMAT, peercaps);
556 if (peercaps && !gst_caps_is_any (peercaps)) {
557 /* Prefer the first caps we are compatible with that the peer proposed */
558 caps = gst_caps_intersect_full (peercaps, thiscaps,
559 GST_CAPS_INTERSECT_FIRST);
561 GST_DEBUG_OBJECT (basesrc, "intersect: %" GST_PTR_FORMAT, caps);
563 gst_caps_unref (thiscaps);
565 /* no peer or peer have ANY caps, work with our own caps then */
571 if (!gst_caps_is_empty (caps)) {
572 GstStructure *pref = NULL;
574 if (peercaps && !gst_caps_is_any (peercaps))
575 pref = gst_caps_get_structure (peercaps, 0);
577 caps = gst_v4l2src_fixate (basesrc, caps, pref);
579 /* Fixating may fail as we now set the selected format */
585 GST_DEBUG_OBJECT (basesrc, "fixated to: %" GST_PTR_FORMAT, caps);
587 if (gst_caps_is_any (caps)) {
588 /* hmm, still anything, so element can do anything and
589 * nego is not needed */
591 } else if (gst_caps_is_fixed (caps)) {
592 /* yay, fixed caps, use those then */
593 result = gst_base_src_set_caps (basesrc, caps);
596 gst_caps_unref (caps);
601 gst_caps_unref (peercaps);
607 GST_DEBUG_OBJECT (basesrc, "no negotiation needed");
609 gst_caps_unref (thiscaps);
615 gst_v4l2src_get_caps (GstBaseSrc * src, GstCaps * filter)
620 v4l2src = GST_V4L2SRC (src);
621 obj = v4l2src->v4l2object;
623 if (!GST_V4L2_IS_OPEN (obj)) {
624 return gst_pad_get_pad_template_caps (GST_BASE_SRC_PAD (v4l2src));
627 return gst_v4l2_object_get_caps (obj, filter);
631 gst_v4l2src_decide_allocation (GstBaseSrc * bsrc, GstQuery * query)
633 GstV4l2Src *src = GST_V4L2SRC (bsrc);
636 if (src->pending_set_fmt) {
637 GstCaps *caps = gst_pad_get_current_caps (GST_BASE_SRC_PAD (bsrc));
638 GstV4l2Error error = GST_V4L2_ERROR_INIT;
640 caps = gst_caps_make_writable (caps);
641 if (!(ret = gst_v4l2src_set_format (src, caps, &error)))
642 gst_v4l2_error (src, &error);
644 gst_caps_unref (caps);
645 src->pending_set_fmt = FALSE;
646 } else if (gst_buffer_pool_is_active (src->v4l2object->pool)) {
647 /* Trick basesrc into not deactivating the active pool. Renegotiating here
648 * would otherwise turn off and on the camera. */
649 GstAllocator *allocator;
650 GstAllocationParams params;
653 gst_base_src_get_allocator (bsrc, &allocator, ¶ms);
654 pool = gst_base_src_get_buffer_pool (bsrc);
656 if (gst_query_get_n_allocation_params (query))
657 gst_query_set_nth_allocation_param (query, 0, allocator, ¶ms);
659 gst_query_add_allocation_param (query, allocator, ¶ms);
661 if (gst_query_get_n_allocation_pools (query))
662 gst_query_set_nth_allocation_pool (query, 0, pool,
663 src->v4l2object->info.size, 1, 0);
665 gst_query_add_allocation_pool (query, pool, src->v4l2object->info.size, 1,
669 gst_object_unref (pool);
671 gst_object_unref (allocator);
673 return GST_BASE_SRC_CLASS (parent_class)->decide_allocation (bsrc, query);
677 ret = gst_v4l2_object_decide_allocation (src->v4l2object, query);
679 ret = GST_BASE_SRC_CLASS (parent_class)->decide_allocation (bsrc, query);
683 if (!gst_buffer_pool_set_active (src->v4l2object->pool, TRUE))
684 goto activate_failed;
691 GST_ELEMENT_ERROR (src, RESOURCE, SETTINGS,
692 (_("Failed to allocate required memory.")),
693 ("Buffer pool activation failed"));
699 gst_v4l2src_query (GstBaseSrc * bsrc, GstQuery * query)
703 gboolean res = FALSE;
705 src = GST_V4L2SRC (bsrc);
706 obj = src->v4l2object;
708 switch (GST_QUERY_TYPE (query)) {
709 case GST_QUERY_LATENCY:{
710 GstClockTime min_latency, max_latency;
711 guint32 fps_n, fps_d;
712 guint num_buffers = 0;
714 /* device must be open */
715 if (!GST_V4L2_IS_OPEN (obj)) {
716 GST_WARNING_OBJECT (src,
717 "Can't give latency since device isn't open !");
721 fps_n = GST_V4L2_FPS_N (obj);
722 fps_d = GST_V4L2_FPS_D (obj);
724 /* we must have a framerate */
725 if (fps_n <= 0 || fps_d <= 0) {
726 GST_WARNING_OBJECT (src,
727 "Can't give latency since framerate isn't fixated !");
731 /* min latency is the time to capture one frame */
732 min_latency = gst_util_uint64_scale_int (GST_SECOND, fps_d, fps_n);
734 /* max latency is total duration of the frame buffer */
735 if (obj->pool != NULL)
736 num_buffers = GST_V4L2_BUFFER_POOL_CAST (obj->pool)->max_latency;
738 if (num_buffers == 0)
741 max_latency = num_buffers * min_latency;
743 GST_DEBUG_OBJECT (bsrc,
744 "report latency min %" GST_TIME_FORMAT " max %" GST_TIME_FORMAT,
745 GST_TIME_ARGS (min_latency), GST_TIME_ARGS (max_latency));
747 /* we are always live, the min latency is 1 frame and the max latency is
748 * the complete buffer of frames. */
749 gst_query_set_latency (query, TRUE, min_latency, max_latency);
755 res = GST_BASE_SRC_CLASS (parent_class)->query (bsrc, query);
764 /* start and stop are not symmetric -- start will open the device, but not start
765 * capture. it's setcaps that will start capture, which is called via basesrc's
766 * negotiate method. stop will both stop capture and close the device.
769 gst_v4l2src_start (GstBaseSrc * src)
771 GstV4l2Src *v4l2src = GST_V4L2SRC (src);
774 v4l2src->renegotiation_adjust = 0;
776 /* activate settings for first frame */
777 v4l2src->ctrl_time = 0;
778 gst_object_sync_values (GST_OBJECT (src), v4l2src->ctrl_time);
780 v4l2src->has_bad_timestamp = FALSE;
781 v4l2src->last_timestamp = 0;
787 gst_v4l2src_unlock (GstBaseSrc * src)
789 GstV4l2Src *v4l2src = GST_V4L2SRC (src);
790 return gst_v4l2_object_unlock (v4l2src->v4l2object);
794 gst_v4l2src_unlock_stop (GstBaseSrc * src)
796 GstV4l2Src *v4l2src = GST_V4L2SRC (src);
798 v4l2src->last_timestamp = 0;
800 return gst_v4l2_object_unlock_stop (v4l2src->v4l2object);
804 gst_v4l2src_stop (GstBaseSrc * src)
806 GstV4l2Src *v4l2src = GST_V4L2SRC (src);
807 GstV4l2Object *obj = v4l2src->v4l2object;
809 if (GST_V4L2_IS_ACTIVE (obj)) {
810 if (!gst_v4l2_object_stop (obj))
814 v4l2src->pending_set_fmt = FALSE;
819 static GstStateChangeReturn
820 gst_v4l2src_change_state (GstElement * element, GstStateChange transition)
822 GstStateChangeReturn ret = GST_STATE_CHANGE_SUCCESS;
823 GstV4l2Src *v4l2src = GST_V4L2SRC (element);
824 GstV4l2Object *obj = v4l2src->v4l2object;
826 switch (transition) {
827 case GST_STATE_CHANGE_NULL_TO_READY:
828 /* open the device */
829 if (!gst_v4l2_object_open (obj))
830 return GST_STATE_CHANGE_FAILURE;
836 ret = GST_ELEMENT_CLASS (parent_class)->change_state (element, transition);
838 switch (transition) {
839 case GST_STATE_CHANGE_READY_TO_NULL:
840 /* close the device */
841 if (!gst_v4l2_object_close (obj))
842 return GST_STATE_CHANGE_FAILURE;
853 gst_v4l2src_create (GstPushSrc * src, GstBuffer ** buf)
855 GstV4l2Src *v4l2src = GST_V4L2SRC (src);
856 GstV4l2Object *obj = v4l2src->v4l2object;
857 GstV4l2BufferPool *pool = GST_V4L2_BUFFER_POOL_CAST (obj->pool);
860 GstClockTime abs_time, base_time, timestamp, duration;
865 ret = GST_BASE_SRC_CLASS (parent_class)->alloc (GST_BASE_SRC (src), 0,
866 obj->info.size, buf);
868 if (G_UNLIKELY (ret != GST_FLOW_OK))
871 ret = gst_v4l2_buffer_pool_process (pool, buf);
873 } while (ret == GST_V4L2_FLOW_CORRUPTED_BUFFER);
875 if (G_UNLIKELY (ret != GST_FLOW_OK))
878 timestamp = GST_BUFFER_TIMESTAMP (*buf);
879 duration = obj->duration;
881 /* timestamps, LOCK to get clock and base time. */
882 /* FIXME: element clock and base_time is rarely changing */
883 GST_OBJECT_LOCK (v4l2src);
884 if ((clock = GST_ELEMENT_CLOCK (v4l2src))) {
885 /* we have a clock, get base time and ref clock */
886 base_time = GST_ELEMENT (v4l2src)->base_time;
887 gst_object_ref (clock);
889 /* no clock, can't set timestamps */
890 base_time = GST_CLOCK_TIME_NONE;
892 GST_OBJECT_UNLOCK (v4l2src);
894 /* sample pipeline clock */
896 abs_time = gst_clock_get_time (clock);
897 gst_object_unref (clock);
899 abs_time = GST_CLOCK_TIME_NONE;
903 if (!v4l2src->has_bad_timestamp && timestamp != GST_CLOCK_TIME_NONE) {
907 /* v4l2 specs say to use the system time although many drivers switched to
908 * the more desirable monotonic time. We first try to use the monotonic time
909 * and see how that goes */
910 clock_gettime (CLOCK_MONOTONIC, &now);
911 gstnow = GST_TIMESPEC_TO_TIME (now);
913 if (timestamp > gstnow || (gstnow - timestamp) > (10 * GST_SECOND)) {
916 /* very large diff, fall back to system time */
917 g_get_current_time (&now);
918 gstnow = GST_TIMEVAL_TO_TIME (now);
921 /* Detect buggy drivers here, and stop using their timestamp. Failing any
922 * of these condition would imply a very buggy driver:
923 * - Timestamp in the future
924 * - Timestamp is going backward compare to last seen timestamp
925 * - Timestamp is jumping forward for less then a frame duration
926 * - Delay is bigger then the actual timestamp
928 if (timestamp > gstnow) {
929 GST_WARNING_OBJECT (v4l2src,
930 "Timestamp in the future detected, ignoring driver timestamps");
931 v4l2src->has_bad_timestamp = TRUE;
935 if (v4l2src->last_timestamp > timestamp) {
936 GST_WARNING_OBJECT (v4l2src,
937 "Timestamp going backward, ignoring driver timestamps");
938 v4l2src->has_bad_timestamp = TRUE;
942 delay = gstnow - timestamp;
944 if (delay > timestamp) {
945 GST_WARNING_OBJECT (v4l2src,
946 "Timestamp does not correlate with any clock, ignoring driver timestamps");
947 v4l2src->has_bad_timestamp = TRUE;
951 /* Save last timestamp for sanity checks */
952 v4l2src->last_timestamp = timestamp;
954 GST_DEBUG_OBJECT (v4l2src, "ts: %" GST_TIME_FORMAT " now %" GST_TIME_FORMAT
955 " delay %" GST_TIME_FORMAT, GST_TIME_ARGS (timestamp),
956 GST_TIME_ARGS (gstnow), GST_TIME_ARGS (delay));
958 /* we assume 1 frame latency otherwise */
959 if (GST_CLOCK_TIME_IS_VALID (duration))
965 /* set buffer metadata */
967 if (G_LIKELY (abs_time != GST_CLOCK_TIME_NONE)) {
968 /* the time now is the time of the clock minus the base time */
969 timestamp = abs_time - base_time;
971 /* adjust for delay in the device */
972 if (timestamp > delay)
977 timestamp = GST_CLOCK_TIME_NONE;
980 /* activate settings for next frame */
981 if (GST_CLOCK_TIME_IS_VALID (duration)) {
982 v4l2src->ctrl_time += duration;
984 /* this is not very good (as it should be the next timestamp),
985 * still good enough for linear fades (as long as it is not -1)
987 v4l2src->ctrl_time = timestamp;
989 gst_object_sync_values (GST_OBJECT (src), v4l2src->ctrl_time);
991 GST_INFO_OBJECT (src, "sync to %" GST_TIME_FORMAT " out ts %" GST_TIME_FORMAT,
992 GST_TIME_ARGS (v4l2src->ctrl_time), GST_TIME_ARGS (timestamp));
994 /* use generated offset values only if there are not already valid ones
995 * set by the v4l2 device */
996 if (!GST_BUFFER_OFFSET_IS_VALID (*buf)
997 || !GST_BUFFER_OFFSET_END_IS_VALID (*buf)) {
998 GST_BUFFER_OFFSET (*buf) = v4l2src->offset++;
999 GST_BUFFER_OFFSET_END (*buf) = v4l2src->offset;
1001 /* adjust raw v4l2 device sequence, will restart at null in case of renegotiation
1002 * (streamoff/streamon) */
1003 GST_BUFFER_OFFSET (*buf) += v4l2src->renegotiation_adjust;
1004 GST_BUFFER_OFFSET_END (*buf) += v4l2src->renegotiation_adjust;
1005 /* check for frame loss with given (from v4l2 device) buffer offset */
1006 if ((v4l2src->offset != 0)
1007 && (GST_BUFFER_OFFSET (*buf) != (v4l2src->offset + 1))) {
1008 guint64 lost_frame_count = GST_BUFFER_OFFSET (*buf) - v4l2src->offset - 1;
1009 GST_WARNING_OBJECT (v4l2src,
1010 "lost frames detected: count = %" G_GUINT64_FORMAT " - ts: %"
1011 GST_TIME_FORMAT, lost_frame_count, GST_TIME_ARGS (timestamp));
1013 qos_msg = gst_message_new_qos (GST_OBJECT_CAST (v4l2src), TRUE,
1014 GST_CLOCK_TIME_NONE, GST_CLOCK_TIME_NONE, timestamp,
1015 GST_CLOCK_TIME_IS_VALID (duration) ? lost_frame_count *
1016 duration : GST_CLOCK_TIME_NONE);
1017 gst_element_post_message (GST_ELEMENT_CAST (v4l2src), qos_msg);
1020 v4l2src->offset = GST_BUFFER_OFFSET (*buf);
1023 GST_BUFFER_TIMESTAMP (*buf) = timestamp;
1024 GST_BUFFER_DURATION (*buf) = duration;
1031 if (ret != GST_FLOW_FLUSHING)
1032 GST_ELEMENT_ERROR (src, RESOURCE, NO_SPACE_LEFT,
1033 ("Failed to allocate a buffer"), (NULL));
1038 gst_buffer_replace (buf, NULL);
1039 if (ret == GST_V4L2_FLOW_LAST_BUFFER) {
1040 GST_ELEMENT_ERROR (src, RESOURCE, FAILED,
1041 ("Driver returned a buffer with no payload, this most likely "
1042 "indicate a bug in the driver."), (NULL));
1043 ret = GST_FLOW_ERROR;
1045 GST_DEBUG_OBJECT (src, "error processing buffer %d (%s)", ret,
1046 gst_flow_get_name (ret));
1053 /* GstURIHandler interface */
1055 gst_v4l2src_uri_get_type (GType type)
1060 static const gchar *const *
1061 gst_v4l2src_uri_get_protocols (GType type)
1063 static const gchar *protocols[] = { "v4l2", NULL };
1069 gst_v4l2src_uri_get_uri (GstURIHandler * handler)
1071 GstV4l2Src *v4l2src = GST_V4L2SRC (handler);
1073 if (v4l2src->v4l2object->videodev != NULL) {
1074 return g_strdup_printf ("v4l2://%s", v4l2src->v4l2object->videodev);
1077 return g_strdup ("v4l2://");
1081 gst_v4l2src_uri_set_uri (GstURIHandler * handler, const gchar * uri,
1084 GstV4l2Src *v4l2src = GST_V4L2SRC (handler);
1085 const gchar *device = DEFAULT_PROP_DEVICE;
1087 if (strcmp (uri, "v4l2://") != 0) {
1090 g_object_set (v4l2src, "device", device, NULL);
1097 gst_v4l2src_uri_handler_init (gpointer g_iface, gpointer iface_data)
1099 GstURIHandlerInterface *iface = (GstURIHandlerInterface *) g_iface;
1101 iface->get_type = gst_v4l2src_uri_get_type;
1102 iface->get_protocols = gst_v4l2src_uri_get_protocols;
1103 iface->get_uri = gst_v4l2src_uri_get_uri;
1104 iface->set_uri = gst_v4l2src_uri_set_uri;