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806ff70590
Crossfading is a bit more complex than just having two pads with the right keyframes as the blending is not exactly the same. The difference is in the way we compute the alpha channel, in the case of crossfading, we have to compute an additive operation between the destination and the source (factored by the alpha property of both the input pad alpha property and the crossfading ratio) basically so that the crossfade result of 2 opaque frames is also fully opaque at any time in the crossfading process, avoid bleeding through the layer blending. Some rationnal can be found in https://phabricator.freedesktop.org/T7773. https://bugzilla.gnome.org/show_bug.cgi?id=784827
111 lines
4.1 KiB
C
111 lines
4.1 KiB
C
/* Generic video aggregator plugin
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* Copyright (C) 2008 Wim Taymans <wim@fluendo.com>
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* Copyright (C) 2010 Sebastian Dröge <sebastian.droege@collabora.co.uk>
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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*
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* You should have received a copy of the GNU Library General Public
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* License along with this library; if not, write to the
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* Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
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* Boston, MA 02110-1301, USA.
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*/
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#ifndef __GST_VIDEO_AGGREGATOR_PAD_H__
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#define __GST_VIDEO_AGGREGATOR_PAD_H__
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#include <gst/gst.h>
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#include <gst/video/video.h>
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#include <gst/base/gstaggregator.h>
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#include "gstvideoaggregator.h"
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G_BEGIN_DECLS
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#define GST_TYPE_VIDEO_AGGREGATOR_PAD (gst_video_aggregator_pad_get_type())
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#define GST_VIDEO_AGGREGATOR_PAD(obj) \
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(G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_VIDEO_AGGREGATOR_PAD, GstVideoAggregatorPad))
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#define GST_VIDEO_AGGREGATOR_PAD_CLASS(klass) \
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(G_TYPE_CHECK_CLASS_CAST((klass),GST_TYPE_COMPOSITOR_PAD, GstVideoAggregatorPadClass))
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#define GST_IS_VIDEO_AGGREGATOR_PAD(obj) \
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(G_TYPE_CHECK_INSTANCE_TYPE((obj),GST_TYPE_VIDEO_AGGREGATOR_PAD))
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#define GST_IS_VIDEO_AGGREGATOR_PAD_CLASS(klass) \
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(G_TYPE_CHECK_CLASS_TYPE((klass),GST_TYPE_VIDEO_AGGREGATOR_PAD))
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#define GST_VIDEO_AGGREGATOR_PAD_GET_CLASS(obj) \
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(G_TYPE_INSTANCE_GET_CLASS((obj),GST_TYPE_VIDEO_AGGREGATOR_PAD,GstVideoAggregatorPadClass))
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typedef struct _GstVideoAggregatorPad GstVideoAggregatorPad;
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typedef struct _GstVideoAggregatorPadClass GstVideoAggregatorPadClass;
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typedef struct _GstVideoAggregatorPadPrivate GstVideoAggregatorPadPrivate;
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/**
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* GstVideoAggregatorPad:
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* @info: The #GstVideoInfo currently set on the pad
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* @buffer_vinfo: The #GstVideoInfo representing the type contained
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* in @buffer
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* @aggregated_frame: The #GstVideoFrame ready to be used for aggregation
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* inside the aggregate_frames vmethod.
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* @zorder: The zorder of this pad
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*/
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struct _GstVideoAggregatorPad
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{
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GstAggregatorPad parent;
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GstVideoInfo info;
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GstBuffer *buffer;
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GstVideoFrame *aggregated_frame;
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/* properties */
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guint zorder;
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gboolean ignore_eos;
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/* < private > */
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GstVideoAggregatorPadPrivate *priv;
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union {
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/* Subclasses can force an alpha channel in the (input thus output)
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* colorspace format */
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gboolean needs_alpha;
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gpointer _gst_reserved[GST_PADDING];
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} ABI;
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};
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/**
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* GstVideoAggregatorPadClass:
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*
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* @set_info: Lets subclass set a converter on the pad,
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* right after a new format has been negotiated.
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* @prepare_frame: Prepare the frame from the pad buffer (if any)
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* and sets it to @aggregated_frame
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* @clean_frame: clean the frame previously prepared in prepare_frame
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*/
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struct _GstVideoAggregatorPadClass
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{
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GstAggregatorPadClass parent_class;
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gboolean (*set_info) (GstVideoAggregatorPad * pad,
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GstVideoAggregator * videoaggregator,
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GstVideoInfo * current_info,
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GstVideoInfo * wanted_info);
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gboolean (*prepare_frame) (GstVideoAggregatorPad * pad,
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GstVideoAggregator * videoaggregator);
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void (*clean_frame) (GstVideoAggregatorPad * pad,
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GstVideoAggregator * videoaggregator);
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gpointer _gst_reserved[GST_PADDING_LARGE];
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};
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GST_EXPORT
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GType gst_video_aggregator_pad_get_type (void);
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G_END_DECLS
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#endif /* __GST_VIDEO_AGGREGATOR_PAD_H__ */
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