From 4dbf61d1ef1441a7600346cec970e272512a4319 Mon Sep 17 00:00:00 2001
From: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Date: Tue, 30 Mar 2021 15:34:11 -0400
Subject: [PATCH] alphacodecdemux: Implement meta demuxing
Produce two streams from a buffer that has GstVideoCodecAlphaMeta
attached.
Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-bad/-/merge_requests/2199>
---
gst/codecalpha/gstcodecalphademux.c | 223 +++++++++++++++++++++++++++-
1 file changed, 217 insertions(+), 6 deletions(-)
diff --git a/gst/codecalpha/gstcodecalphademux.c b/gst/codecalpha/gstcodecalphademux.c
index 2d013bce82..bb0b0ca7f2 100644
--- a/gst/codecalpha/gstcodecalphademux.c
+++ b/gst/codecalpha/gstcodecalphademux.c
@@ -22,9 +22,9 @@
* SECTION:element-codecalphademux
* @title: CODEC Alpha Demuxer
*
- * Extract the CODEC (typically VP8/VP9) alpha stream stored at meta and
- * expose it as a stream. This element allow using single stream VP9 decoders
- * in order to decode both streams.
+ * 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
* |[
@@ -33,8 +33,9 @@
* 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 window.
+ * the result on seperate windows.
*
+ * Since: 1.20
*/
#ifdef HAVE_CONFIG_H
@@ -42,6 +43,8 @@
#endif
#include <gst/video/video.h>
+#include <gst/base/gstflowcombiner.h>
+
#include "gstcodecalphademux.h"
GST_DEBUG_CATEGORY_STATIC (codecalphademux_debug);
@@ -50,10 +53,16 @@ GST_DEBUG_CATEGORY_STATIC (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,
+G_DEFINE_TYPE_WITH_CODE (GstCodecAlphaDemux, gst_codec_alpha_demux,
GST_TYPE_ELEMENT,
GST_DEBUG_CATEGORY_INIT (codecalphademux_debug, "codecalphademux", 0,
"codecalphademux"));
@@ -82,10 +91,187 @@ GST_STATIC_PAD_TEMPLATE ("alpha",
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;
+
+ if (alpha_meta)
+ alpha_buffer = gst_buffer_ref (alpha_meta->buffer);
+
+ ret = gst_flow_combiner_update_pad_flow (self->flow_combiner,
+ self->src_pad, gst_pad_push (self->src_pad, buffer));
+
+ /* we lost ownership here */
+ buffer = NULL;
+ alpha_meta = NULL;
+
+ if (alpha_buffer)
+ ret = gst_flow_combiner_update_pad_flow (self->flow_combiner,
+ self->alpha_pad, gst_pad_push (self->alpha_pad, alpha_buffer));
+ else
+ ret = gst_flow_combiner_update_pad_flow (self->flow_combiner,
+ self->alpha_pad, gst_pad_push_event (self->alpha_pad,
+ gst_event_new_gap (pts, duration)));
+
+
+ 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",
@@ -98,9 +284,34 @@ gst_codec_alpha_demux_class_init (GstCodecAlphaDemuxClass * klass)
&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 * demux)
+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);
}