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156 lines
4.3 KiB
C
156 lines
4.3 KiB
C
/* GStreamer
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* Copyright (C) 2021 Collabora Ltd.
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* Author: Nicolas Dufresne <nicolas.dufresne@collabora.com>
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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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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#include "gstvideocodecalphameta.h"
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/**
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* SECTION:gstvideocodecalphameta
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* @title: GstVideoCodecAlphaMeta
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* @short_description: GstMeta that can carry an extra buffer holding an
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* encoded a frame whith luma that can be used as an alpha channel.
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*
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* This meta is primarily for internal use in GStreamer elements to support
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* VP8/VP9 transparent video stored into WebM or Matroska containers, or
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* transparent static AV1 images. Nothing prevents you from using this meta
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* for custom purposes, but it generally can't be used to easily to add support
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* for alpha channels to CODECs or formats that don't support that out of the
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* box.
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*
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* Since: 1.20
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*/
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/**
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* gst_video_codec_alpha_meta_api_get_type:
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*
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* Returns: #GType for the #GstVideoCodecAlphaMeta structure.
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*
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* Since: 1.20
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*/
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GType
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gst_video_codec_alpha_meta_api_get_type (void)
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{
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static GType type = 0;
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static const gchar *tags[] = { GST_META_TAG_VIDEO_STR, NULL };
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if (g_once_init_enter (&type)) {
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GType _type =
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gst_meta_api_type_register ("GstVideoCodecAlphaMetaAPI", tags);
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g_once_init_leave (&type, _type);
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}
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return type;
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}
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static gboolean
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gst_video_codec_alpha_meta_transform (GstBuffer * dest,
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GstMeta * meta, GstBuffer * buffer, GQuark type, gpointer data)
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{
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GstVideoCodecAlphaMeta *dmeta, *smeta;
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smeta = (GstVideoCodecAlphaMeta *) meta;
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if (GST_META_TRANSFORM_IS_COPY (type)) {
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dmeta =
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(GstVideoCodecAlphaMeta *) gst_buffer_add_meta (dest,
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GST_VIDEO_CODEC_ALPHA_META_INFO, NULL);
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if (!dmeta)
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return FALSE;
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dmeta->buffer = gst_buffer_ref (smeta->buffer);
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}
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return TRUE;
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}
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static gboolean
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gst_video_codec_alpha_meta_init (GstMeta * meta, gpointer params,
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GstBuffer * buffer)
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{
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GstVideoCodecAlphaMeta *ca_meta = (GstVideoCodecAlphaMeta *) meta;
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/* the buffer ownership is transfered to the Meta */
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ca_meta->buffer = (GstBuffer *) params;
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return TRUE;
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}
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static void
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gst_video_codec_alpha_meta_free (GstMeta * meta, GstBuffer * buffer)
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{
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GstVideoCodecAlphaMeta *ca_meta = (GstVideoCodecAlphaMeta *) meta;
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gst_clear_buffer (&ca_meta->buffer);
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}
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/**
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* gst_video_codec_alpha_meta_get_info:
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*
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* Returns: #GstMetaInfo pointer that describes #GstVideoCodecAlphaMeta.
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*
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* Since: 1.20
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*/
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const GstMetaInfo *
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gst_video_codec_alpha_meta_get_info (void)
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{
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static const GstMetaInfo *info = NULL;
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if (g_once_init_enter ((GstMetaInfo **) & info)) {
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const GstMetaInfo *meta =
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gst_meta_register (GST_VIDEO_CODEC_ALPHA_META_API_TYPE,
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"GstVideoCodecAlphaMeta",
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sizeof (GstVideoCodecAlphaMeta),
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gst_video_codec_alpha_meta_init,
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gst_video_codec_alpha_meta_free,
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gst_video_codec_alpha_meta_transform);
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g_once_init_leave ((GstMetaInfo **) & info, (GstMetaInfo *) meta);
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}
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return info;
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}
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/**
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* gst_buffer_add_video_codec_alpha_meta:
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* @buffer: (transfer none): a #GstBuffer
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* @alpha_buffer: (transfer full): a #GstBuffer
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*
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* Attaches a #GstVideoCodecAlphaMeta metadata to @buffer with
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* the given alpha buffer.
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*
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* Returns: (transfer none): the #GstVideoCodecAlphaMeta on @buffer.
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*
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* Since: 1.20
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*/
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GstVideoCodecAlphaMeta *
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gst_buffer_add_video_codec_alpha_meta (GstBuffer * buffer,
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GstBuffer * alpha_buffer)
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{
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GstVideoCodecAlphaMeta *meta;
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g_return_val_if_fail (buffer != NULL, NULL);
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g_return_val_if_fail (alpha_buffer != NULL, NULL);
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meta =
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(GstVideoCodecAlphaMeta *) gst_buffer_add_meta (buffer,
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GST_VIDEO_CODEC_ALPHA_META_INFO, alpha_buffer);
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return meta;
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}
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