gstreamer/ext/closedcaption/gstccextractor.c

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/*
* GStreamer
* Copyright (C) 2018 Edward Hervey <edward@centricular.com>
*
* 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.
*/
/**
* SECTION:element-ccextractor
* @title: ccextractor
* @short_description: Extract GstVideoCaptionMeta from input stream
*
* Note: This element must be added after a pipeline's decoder, otherwise closed captions may
* be extracted out of order.
*
*/
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include <gst/gst.h>
#include <gst/video/video.h>
#include <string.h>
#include "gstccextractor.h"
GST_DEBUG_CATEGORY_STATIC (gst_cc_extractor_debug);
#define GST_CAT_DEFAULT gst_cc_extractor_debug
enum
{
PROP_0,
PROP_REMOVE_CAPTION_META,
};
static GstStaticPadTemplate sinktemplate = GST_STATIC_PAD_TEMPLATE ("sink",
GST_PAD_SINK,
GST_PAD_ALWAYS,
GST_STATIC_CAPS_ANY);
static GstStaticPadTemplate srctemplate = GST_STATIC_PAD_TEMPLATE ("src",
GST_PAD_SRC,
GST_PAD_ALWAYS,
GST_STATIC_CAPS_ANY);
static GstStaticPadTemplate captiontemplate =
GST_STATIC_PAD_TEMPLATE ("caption",
GST_PAD_SRC,
GST_PAD_SOMETIMES,
GST_STATIC_CAPS
("closedcaption/x-cea-608,format={ (string) raw, (string) s334-1a}; "
"closedcaption/x-cea-708,format={ (string) cc_data, (string) cdp }"));
G_DEFINE_TYPE (GstCCExtractor, gst_cc_extractor, GST_TYPE_ELEMENT);
#define parent_class gst_cc_extractor_parent_class
static gboolean gst_cc_extractor_sink_event (GstPad * pad, GstObject * parent,
GstEvent * event);
static gboolean gst_cc_extractor_sink_query (GstPad * pad, GstObject * parent,
GstQuery * query);
static GstFlowReturn gst_cc_extractor_chain (GstPad * pad, GstObject * parent,
GstBuffer * buf);
static GstStateChangeReturn gst_cc_extractor_change_state (GstElement *
element, GstStateChange transition);
static void gst_cc_extractor_finalize (GObject * self);
static void gst_cc_extractor_set_property (GObject * self, guint prop_id,
const GValue * value, GParamSpec * pspec);
static void gst_cc_extractor_get_property (GObject * self, guint prop_id,
GValue * value, GParamSpec * pspec);
static void
gst_cc_extractor_class_init (GstCCExtractorClass * klass)
{
GObjectClass *gobject_class;
GstElementClass *gstelement_class;
gobject_class = (GObjectClass *) klass;
gstelement_class = (GstElementClass *) klass;
gobject_class->finalize = gst_cc_extractor_finalize;
gobject_class->set_property = gst_cc_extractor_set_property;
gobject_class->get_property = gst_cc_extractor_get_property;
/**
* GstCCExtractor:remove-caption-meta
*
* Selects whether the #GstVideoCaptionMeta should be removed from the
* outgoing video buffers or whether it should be kept.
*
* Since: 1.18
*/
g_object_class_install_property (G_OBJECT_CLASS (klass),
PROP_REMOVE_CAPTION_META, g_param_spec_boolean ("remove-caption-meta",
"Remove Caption Meta",
"Remove caption meta from outgoing video buffers", FALSE,
G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
gstelement_class->change_state =
GST_DEBUG_FUNCPTR (gst_cc_extractor_change_state);
gst_element_class_set_static_metadata (gstelement_class,
"Closed Caption Extractor",
"Filter",
"Extract GstVideoCaptionMeta from input stream",
"Edward Hervey <edward@centricular.com>");
gst_element_class_add_static_pad_template (gstelement_class, &sinktemplate);
gst_element_class_add_static_pad_template (gstelement_class, &srctemplate);
gst_element_class_add_static_pad_template (gstelement_class,
&captiontemplate);
GST_DEBUG_CATEGORY_INIT (gst_cc_extractor_debug, "ccextractor",
0, "Closed Caption extractor");
}
static GstIterator *
gst_cc_extractor_iterate_internal_links (GstPad * pad, GstObject * parent)
{
GstCCExtractor *filter = (GstCCExtractor *) parent;
GstIterator *it = NULL;
GstPad *opad = NULL;
if (pad == filter->sinkpad)
opad = filter->srcpad;
else if (pad == filter->srcpad || pad == filter->captionpad)
opad = filter->sinkpad;
if (opad) {
GValue value = { 0, };
g_value_init (&value, GST_TYPE_PAD);
g_value_set_object (&value, opad);
it = gst_iterator_new_single (GST_TYPE_PAD, &value);
g_value_unset (&value);
}
return it;
}
static void
gst_cc_extractor_reset (GstCCExtractor * filter)
{
filter->caption_type = GST_VIDEO_CAPTION_TYPE_UNKNOWN;
gst_flow_combiner_reset (filter->combiner);
gst_flow_combiner_add_pad (filter->combiner, filter->srcpad);
if (filter->captionpad) {
gst_flow_combiner_remove_pad (filter->combiner, filter->captionpad);
gst_pad_set_active (filter->captionpad, FALSE);
gst_element_remove_pad ((GstElement *) filter, filter->captionpad);
filter->captionpad = NULL;
}
memset (&filter->video_info, 0, sizeof (filter->video_info));
}
static void
gst_cc_extractor_init (GstCCExtractor * filter)
{
filter->sinkpad = gst_pad_new_from_static_template (&sinktemplate, "sink");
gst_pad_set_event_function (filter->sinkpad,
GST_DEBUG_FUNCPTR (gst_cc_extractor_sink_event));
gst_pad_set_query_function (filter->sinkpad,
GST_DEBUG_FUNCPTR (gst_cc_extractor_sink_query));
gst_pad_set_chain_function (filter->sinkpad,
GST_DEBUG_FUNCPTR (gst_cc_extractor_chain));
gst_pad_set_iterate_internal_links_function (filter->sinkpad,
GST_DEBUG_FUNCPTR (gst_cc_extractor_iterate_internal_links));
GST_PAD_SET_PROXY_CAPS (filter->sinkpad);
GST_PAD_SET_PROXY_ALLOCATION (filter->sinkpad);
GST_PAD_SET_PROXY_SCHEDULING (filter->sinkpad);
filter->srcpad = gst_pad_new_from_static_template (&srctemplate, "src");
gst_pad_set_iterate_internal_links_function (filter->srcpad,
GST_DEBUG_FUNCPTR (gst_cc_extractor_iterate_internal_links));
GST_PAD_SET_PROXY_CAPS (filter->srcpad);
GST_PAD_SET_PROXY_ALLOCATION (filter->srcpad);
GST_PAD_SET_PROXY_SCHEDULING (filter->srcpad);
gst_element_add_pad (GST_ELEMENT (filter), filter->sinkpad);
gst_element_add_pad (GST_ELEMENT (filter), filter->srcpad);
filter->combiner = gst_flow_combiner_new ();
gst_cc_extractor_reset (filter);
}
static GstEvent *
create_stream_start_event_from_stream_start_event (GstEvent * event)
{
GstEvent *new_event;
const gchar *stream_id;
gchar *new_stream_id;
guint group_id;
gst_event_parse_stream_start (event, &stream_id);
new_stream_id = g_strdup_printf ("%s/caption", stream_id);
new_event = gst_event_new_stream_start (new_stream_id);
g_free (new_stream_id);
if (gst_event_parse_group_id (event, &group_id))
gst_event_set_group_id (new_event, group_id);
return new_event;
}
static gboolean
gst_cc_extractor_sink_event (GstPad * pad, GstObject * parent, GstEvent * event)
{
GstCCExtractor *filter = GST_CCEXTRACTOR (parent);
GST_LOG_OBJECT (pad, "received %s event: %" GST_PTR_FORMAT,
GST_EVENT_TYPE_NAME (event), event);
switch (GST_EVENT_TYPE (event)) {
case GST_EVENT_CAPS:{
GstCaps *caps;
gst_event_parse_caps (event, &caps);
if (!gst_video_info_from_caps (&filter->video_info, caps)) {
/* We require any kind of video caps here */
gst_event_unref (event);
return FALSE;
}
break;
}
case GST_EVENT_STREAM_START:
if (filter->captionpad) {
GstEvent *new_event =
create_stream_start_event_from_stream_start_event (event);
gst_pad_push_event (filter->captionpad, new_event);
}
break;
default:
/* Also forward all other events to the caption pad if present */
if (filter->captionpad)
gst_pad_push_event (filter->captionpad, gst_event_ref (event));
break;
}
/* This only forwards to the non-caption source pad */
return gst_pad_event_default (pad, parent, event);
}
static gboolean
gst_cc_extractor_sink_query (GstPad * pad, GstObject * parent, GstQuery * query)
{
GST_LOG_OBJECT (pad, "received %s query: %" GST_PTR_FORMAT,
GST_QUERY_TYPE_NAME (query), query);
switch (GST_QUERY_TYPE (query)) {
case GST_QUERY_ACCEPT_CAPS:{
GstCaps *caps;
const GstStructure *s;
gst_query_parse_accept_caps (query, &caps);
/* FIXME: Ideally we would declare this in our caps but there's no way
* to declare caps of type "video/" and "image/" that would match all
* such caps
*/
s = gst_caps_get_structure (caps, 0);
if (s && (g_str_has_prefix (gst_structure_get_name (s), "video/")
|| g_str_has_prefix (gst_structure_get_name (s), "image/")))
gst_query_set_accept_caps_result (query, TRUE);
else
gst_query_set_accept_caps_result (query, FALSE);
return TRUE;
}
default:
break;
}
return gst_pad_query_default (pad, parent, query);
}
static GstCaps *
create_caps_from_caption_type (GstVideoCaptionType caption_type,
const GstVideoInfo * video_info)
{
GstCaps *caption_caps = gst_video_caption_type_to_caps (caption_type);
gst_caps_set_simple (caption_caps, "framerate", GST_TYPE_FRACTION,
video_info->fps_n, video_info->fps_d, NULL);
return caption_caps;
}
static gboolean
forward_sticky_events (GstPad * pad, GstEvent ** event, gpointer user_data)
{
GstCCExtractor *filter = user_data;
switch (GST_EVENT_TYPE (*event)) {
case GST_EVENT_CAPS:{
GstCaps *caption_caps =
create_caps_from_caption_type (filter->caption_type,
&filter->video_info);
if (caption_caps) {
GstEvent *new_event = gst_event_new_caps (caption_caps);
gst_event_set_seqnum (new_event, gst_event_get_seqnum (*event));
gst_pad_store_sticky_event (filter->captionpad, new_event);
gst_event_unref (new_event);
gst_caps_unref (caption_caps);
}
break;
}
case GST_EVENT_STREAM_START:{
GstEvent *new_event =
create_stream_start_event_from_stream_start_event (*event);
gst_pad_store_sticky_event (filter->captionpad, new_event);
gst_event_unref (new_event);
break;
}
default:
gst_pad_store_sticky_event (filter->captionpad, *event);
break;
}
return TRUE;
}
static GstFlowReturn
gst_cc_extractor_handle_meta (GstCCExtractor * filter, GstBuffer * buf,
GstVideoCaptionMeta * meta, GstVideoTimeCodeMeta * tc_meta)
{
GstBuffer *outbuf = NULL;
GstFlowReturn flow;
GST_DEBUG_OBJECT (filter, "Handling meta");
/* Check if the meta type matches the configured one */
if (filter->captionpad == NULL) {
GST_DEBUG_OBJECT (filter, "Creating new caption pad");
/* Create the caption pad and set the caps */
filter->captionpad =
gst_pad_new_from_static_template (&captiontemplate, "caption");
gst_pad_set_iterate_internal_links_function (filter->sinkpad,
GST_DEBUG_FUNCPTR (gst_cc_extractor_iterate_internal_links));
gst_pad_set_active (filter->captionpad, TRUE);
filter->caption_type = meta->caption_type;
gst_pad_sticky_events_foreach (filter->sinkpad, forward_sticky_events,
filter);
if (!gst_pad_has_current_caps (filter->captionpad)) {
GST_ERROR_OBJECT (filter, "Unknown/invalid caption type");
return GST_FLOW_NOT_NEGOTIATED;
}
gst_element_add_pad (GST_ELEMENT (filter), filter->captionpad);
gst_flow_combiner_add_pad (filter->combiner, filter->captionpad);
} else if (meta->caption_type != filter->caption_type) {
GstCaps *caption_caps =
create_caps_from_caption_type (meta->caption_type, &filter->video_info);
GST_DEBUG_OBJECT (filter, "Caption type changed from %d to %d",
filter->caption_type, meta->caption_type);
if (caption_caps == NULL) {
GST_ERROR_OBJECT (filter, "Unknown/invalid caption type");
return GST_FLOW_NOT_NEGOTIATED;
}
gst_pad_push_event (filter->captionpad, gst_event_new_caps (caption_caps));
gst_caps_unref (caption_caps);
filter->caption_type = meta->caption_type;
}
GST_DEBUG_OBJECT (filter,
"Creating new buffer of size %" G_GSIZE_FORMAT " bytes", meta->size);
/* Extract caption data into new buffer with identical buffer timestamps */
outbuf = gst_buffer_new_allocate (NULL, meta->size, NULL);
gst_buffer_fill (outbuf, 0, meta->data, meta->size);
GST_BUFFER_PTS (outbuf) = GST_BUFFER_PTS (buf);
GST_BUFFER_DTS (outbuf) = GST_BUFFER_DTS (buf);
GST_BUFFER_DURATION (outbuf) = GST_BUFFER_DURATION (buf);
if (tc_meta)
gst_buffer_add_video_time_code_meta (outbuf, &tc_meta->tc);
gst_buffer_set_flags (outbuf, gst_buffer_get_flags (buf));
/* We don't really care about the flow return */
flow = gst_pad_push (filter->captionpad, outbuf);
/* Set flow return on pad and return combined value */
return gst_flow_combiner_update_pad_flow (filter->combiner,
filter->captionpad, flow);
}
static gboolean
remove_caption_meta (GstBuffer * buffer, GstMeta ** meta, gpointer user_data)
{
if ((*meta)->info->api == GST_VIDEO_CAPTION_META_API_TYPE)
*meta = NULL;
return TRUE;
}
static GstFlowReturn
gst_cc_extractor_chain (GstPad * pad, GstObject * parent, GstBuffer * buf)
{
GstCCExtractor *filter = (GstCCExtractor *) parent;
GstFlowReturn flow = GST_FLOW_OK;
GstVideoCaptionMeta *cc_meta;
GstVideoTimeCodeMeta *tc_meta;
gboolean had_cc_meta = FALSE;
gpointer iter = NULL;
tc_meta = gst_buffer_get_video_time_code_meta (buf);
while ((cc_meta =
(GstVideoCaptionMeta *) gst_buffer_iterate_meta_filtered (buf, &iter,
GST_VIDEO_CAPTION_META_API_TYPE)) && flow == GST_FLOW_OK) {
had_cc_meta = TRUE;
flow = gst_cc_extractor_handle_meta (filter, buf, cc_meta, tc_meta);
}
/* If there's an issue handling the CC, return immediately */
if (flow != GST_FLOW_OK) {
gst_buffer_unref (buf);
return flow;
}
if (filter->remove_caption_meta) {
buf = gst_buffer_make_writable (buf);
gst_buffer_foreach_meta (buf, remove_caption_meta, NULL);
}
if (!had_cc_meta && filter->captionpad && GST_BUFFER_PTS_IS_VALID (buf)) {
gst_pad_push_event (filter->captionpad,
gst_event_new_gap (GST_BUFFER_PTS (buf), GST_BUFFER_DURATION (buf)));
}
/* Push the buffer downstream and return the combined flow return */
return gst_flow_combiner_update_pad_flow (filter->combiner, filter->srcpad,
gst_pad_push (filter->srcpad, buf));
}
static GstStateChangeReturn
gst_cc_extractor_change_state (GstElement * element, GstStateChange transition)
{
GstStateChangeReturn ret;
GstCCExtractor *filter = GST_CCEXTRACTOR (element);
switch (transition) {
case GST_STATE_CHANGE_NULL_TO_READY:
break;
case GST_STATE_CHANGE_READY_TO_PAUSED:
break;
case GST_STATE_CHANGE_PAUSED_TO_PLAYING:
break;
default:
break;
}
ret = GST_ELEMENT_CLASS (parent_class)->change_state (element, transition);
if (ret != GST_STATE_CHANGE_SUCCESS)
return ret;
switch (transition) {
case GST_STATE_CHANGE_PLAYING_TO_PAUSED:
break;
case GST_STATE_CHANGE_PAUSED_TO_READY:
gst_cc_extractor_reset (filter);
break;
case GST_STATE_CHANGE_READY_TO_NULL:
default:
break;
}
return ret;
}
static void
gst_cc_extractor_finalize (GObject * object)
{
GstCCExtractor *filter = GST_CCEXTRACTOR (object);
gst_flow_combiner_free (filter->combiner);
G_OBJECT_CLASS (parent_class)->finalize (object);
}
static void
gst_cc_extractor_set_property (GObject * object, guint prop_id,
const GValue * value, GParamSpec * pspec)
{
GstCCExtractor *filter = GST_CCEXTRACTOR (object);
switch (prop_id) {
case PROP_REMOVE_CAPTION_META:
filter->remove_caption_meta = g_value_get_boolean (value);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static void
gst_cc_extractor_get_property (GObject * object, guint prop_id, GValue * value,
GParamSpec * pspec)
{
GstCCExtractor *filter = GST_CCEXTRACTOR (object);
switch (prop_id) {
case PROP_REMOVE_CAPTION_META:
g_value_set_boolean (value, filter->remove_caption_meta);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}