gstreamer/subprojects/gst-plugins-bad/gst/codecalpha/gstcodecalphademux.c

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/* GStreamer
* Copyright (C) <2021> Collabora Ltd.
* Author: Nicolas Dufresne <nicolas.dufresne@collabora.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-codecalphademux
* @title: CODEC Alpha Demuxer
*
* Extracts the CODEC (typically VP8/VP9) alpha stream stored as meta and
* exposes it as a stream. This element allow using single stream VP8/9
* decoders in order to decode both streams.
*
* ## Example launch line
* |[
* gst-launch-1.0 -v filesrc location=transparency.webm ! matroskademux !
* codecalphademux name=d
* d.video ! queue ! vp9dec ! autovideosink
* d.alpha ! queue ! vp9dec ! autovideosink
* ]| This pipeline splits and decode the video and the alpha stream, showing
* the result on seperate windows.
*
* Since: 1.20
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <gst/video/video.h>
#include <gst/base/gstflowcombiner.h>
#include "gstcodecalphademux.h"
GST_DEBUG_CATEGORY_STATIC (codecalphademux_debug);
#define GST_CAT_DEFAULT (codecalphademux_debug)
struct _GstCodecAlphaDemux
{
GstElement parent;
GstPad *sink_pad;
GstPad *src_pad;
GstPad *alpha_pad;
GstFlowCombiner *flow_combiner;
};
#define gst_codec_alpha_demux_parent_class parent_class
G_DEFINE_TYPE_WITH_CODE (GstCodecAlphaDemux, gst_codec_alpha_demux,
GST_TYPE_ELEMENT,
GST_DEBUG_CATEGORY_INIT (codecalphademux_debug, "codecalphademux", 0,
"codecalphademux"));
GST_ELEMENT_REGISTER_DEFINE (codec_alpha_demux, "codecalphademux",
GST_RANK_NONE, GST_TYPE_CODEC_ALPHA_DEMUX);
static GstStaticPadTemplate gst_codec_alpha_demux_sink_template =
GST_STATIC_PAD_TEMPLATE ("sink",
GST_PAD_SINK,
GST_PAD_ALWAYS,
GST_STATIC_CAPS ("ANY")
);
static GstStaticPadTemplate gst_codec_alpha_demux_src_template =
GST_STATIC_PAD_TEMPLATE ("src",
GST_PAD_SRC,
GST_PAD_ALWAYS,
GST_STATIC_CAPS ("ANY")
);
static GstStaticPadTemplate gst_codec_alpha_demux_alpha_template =
GST_STATIC_PAD_TEMPLATE ("alpha",
GST_PAD_SRC,
GST_PAD_ALWAYS,
GST_STATIC_CAPS ("ANY")
);
static GstFlowReturn
gst_codec_alpha_demux_chain (GstPad * pad, GstObject * object,
GstBuffer * buffer)
{
GstCodecAlphaDemux *self = GST_CODEC_ALPHA_DEMUX (object);
GstVideoCodecAlphaMeta *alpha_meta =
gst_buffer_get_video_codec_alpha_meta (buffer);
GstBuffer *alpha_buffer = NULL;
GstClockTime pts = GST_BUFFER_PTS (buffer);
GstClockTime duration = GST_BUFFER_DURATION (buffer);
GstFlowReturn ret = GST_FLOW_EOS;
if (alpha_meta)
alpha_buffer = gst_buffer_ref (alpha_meta->buffer);
ret = gst_pad_push (self->src_pad, buffer);
ret = gst_flow_combiner_update_flow (self->flow_combiner, ret);
/* we lost ownership here */
buffer = NULL;
alpha_meta = NULL;
if (alpha_buffer) {
ret = gst_pad_push (self->alpha_pad, alpha_buffer);
} else {
gst_pad_push_event (self->alpha_pad, gst_event_new_gap (pts, duration));
ret = GST_PAD_LAST_FLOW_RETURN (self->alpha_pad);
}
ret = gst_flow_combiner_update_flow (self->flow_combiner, ret);
return ret;
}
static GstCaps *
gst_codec_alpha_demux_transform_caps (GstCaps * caps, gboolean codec_alpha)
{
if (!caps)
return NULL;
caps = gst_caps_copy (caps);
gst_caps_set_simple (caps, "codec-alpha", G_TYPE_BOOLEAN, codec_alpha, NULL);
return caps;
}
static GstEvent *
gst_codec_alpha_demux_transform_caps_event (GstEvent * src_event)
{
GstEvent *dst_event;
GstCaps *caps;
gst_event_parse_caps (src_event, &caps);
caps = gst_codec_alpha_demux_transform_caps (caps, FALSE);
dst_event = gst_event_new_caps (caps);
gst_event_set_seqnum (dst_event, gst_event_get_seqnum (src_event));
gst_caps_unref (caps);
gst_event_unref (src_event);
return dst_event;
}
static gboolean
gst_codec_alpha_demux_sink_event (GstPad * sink_pad, GstObject * parent,
GstEvent * event)
{
GstCodecAlphaDemux *self = GST_CODEC_ALPHA_DEMUX (parent);
switch (event->type) {
case GST_EVENT_FLUSH_STOP:
gst_flow_combiner_reset (self->flow_combiner);
break;
case GST_EVENT_CAPS:
event = gst_codec_alpha_demux_transform_caps_event (event);
break;
default:
break;
}
return gst_pad_event_default (sink_pad, parent, event);
}
static gboolean
gst_codec_alpha_demux_sink_query (GstPad * sink_pad, GstObject * parent,
GstQuery * query)
{
GstQuery *peer_query;
GstCaps *caps;
gboolean ret;
switch (query->type) {
case GST_QUERY_CAPS:
gst_query_parse_caps (query, &caps);
caps = gst_codec_alpha_demux_transform_caps (caps, FALSE);
peer_query = gst_query_new_caps (caps);
gst_clear_caps (&caps);
break;
case GST_QUERY_ACCEPT_CAPS:
gst_query_parse_accept_caps (query, &caps);
caps = gst_codec_alpha_demux_transform_caps (caps, FALSE);
peer_query = gst_query_new_accept_caps (caps);
gst_clear_caps (&caps);
break;
default:
peer_query = query;
break;
}
ret = gst_pad_query_default (sink_pad, parent, peer_query);
if (!ret) {
if (peer_query != query)
gst_query_unref (peer_query);
return FALSE;
}
switch (query->type) {
case GST_QUERY_CAPS:
gst_query_parse_caps_result (peer_query, &caps);
caps = gst_caps_copy (caps);
caps = gst_codec_alpha_demux_transform_caps (caps, TRUE);
gst_query_set_caps_result (query, caps);
gst_caps_unref (caps);
gst_query_unref (peer_query);
break;
case GST_QUERY_ACCEPT_CAPS:
{
gboolean result;
gst_query_parse_accept_caps_result (peer_query, &result);
gst_query_set_accept_caps_result (query, result);
gst_query_unref (peer_query);
break;
}
default:
break;
}
return ret;
}
static void
gst_codec_alpha_demux_start (GstCodecAlphaDemux * self)
{
gst_flow_combiner_reset (self->flow_combiner);
}
static GstStateChangeReturn
gst_codec_alpha_demux_change_state (GstElement * element,
GstStateChange transition)
{
GstCodecAlphaDemux *self = GST_CODEC_ALPHA_DEMUX (element);
switch (transition) {
case GST_STATE_CHANGE_READY_TO_PAUSED:
gst_codec_alpha_demux_start (self);
default:
break;
}
return GST_ELEMENT_CLASS (parent_class)->change_state (element, transition);
}
static void
gst_codec_alpha_demux_dispose (GObject * object)
{
GstCodecAlphaDemux *self = GST_CODEC_ALPHA_DEMUX (object);
g_clear_object (&self->sink_pad);
g_clear_object (&self->src_pad);
g_clear_object (&self->alpha_pad);
g_clear_pointer (&self->flow_combiner, gst_flow_combiner_unref);
G_OBJECT_CLASS (parent_class)->dispose (object);
}
static void
gst_codec_alpha_demux_class_init (GstCodecAlphaDemuxClass * klass)
{
GstElementClass *element_class = (GstElementClass *) klass;
GObjectClass *object_class = (GObjectClass *) klass;
gst_element_class_set_static_metadata (element_class,
"CODEC Alpha Demuxer", "Codec/Demuxer",
"Extract and expose as a stream the CODEC alpha.",
"Nicolas Dufresne <nicolas.dufresne@collabora.com>");
gst_element_class_add_static_pad_template (element_class,
&gst_codec_alpha_demux_sink_template);
gst_element_class_add_static_pad_template (element_class,
&gst_codec_alpha_demux_src_template);
gst_element_class_add_static_pad_template (element_class,
&gst_codec_alpha_demux_alpha_template);
element_class->change_state =
GST_DEBUG_FUNCPTR (gst_codec_alpha_demux_change_state);
object_class->dispose = GST_DEBUG_FUNCPTR (gst_codec_alpha_demux_dispose);
}
static void
gst_codec_alpha_demux_init (GstCodecAlphaDemux * self)
{
gst_element_create_all_pads (GST_ELEMENT (self));
self->sink_pad = gst_element_get_static_pad (GST_ELEMENT (self), "sink");
self->src_pad = gst_element_get_static_pad (GST_ELEMENT (self), "src");
self->alpha_pad = gst_element_get_static_pad (GST_ELEMENT (self), "alpha");
self->flow_combiner = gst_flow_combiner_new ();
gst_flow_combiner_add_pad (self->flow_combiner, self->src_pad);
gst_flow_combiner_add_pad (self->flow_combiner, self->alpha_pad);
GST_PAD_SET_PROXY_CAPS (self->sink_pad);
GST_PAD_SET_PROXY_CAPS (self->src_pad);
GST_PAD_SET_PROXY_CAPS (self->alpha_pad);
GST_PAD_SET_PROXY_SCHEDULING (self->sink_pad);
GST_PAD_SET_PROXY_SCHEDULING (self->src_pad);
GST_PAD_SET_PROXY_SCHEDULING (self->alpha_pad);
gst_pad_set_chain_function (self->sink_pad, gst_codec_alpha_demux_chain);
gst_pad_set_event_function (self->sink_pad, gst_codec_alpha_demux_sink_event);
gst_pad_set_query_function (self->sink_pad, gst_codec_alpha_demux_sink_query);
}