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785e006de9
The GstVideoOverlayComposition only supports unpremultiplied ARGB (for now anyway, support for pre-multiplied alpha is planned.)
114 lines
4.2 KiB
C
114 lines
4.2 KiB
C
/* GStreamer
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* Copyright (C) <1999> Erik Walthinsen <omega@cse.ogi.edu>
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* Copyright (C) <2003> David Schleef <ds@schleef.org>
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* Copyright (C) <2006> Julien Moutte <julien@moutte.net>
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* Copyright (C) <2006> Zeeshan Ali <zeeshan.ali@nokia.com>
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* Copyright (C) <2006-2008> Tim-Philipp Müller <tim centricular net>
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* Copyright (C) <2009> Young-Ho Cha <ganadist@gmail.com>
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* Copyright (C) <2011> 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., 59 Temple Place - Suite 330,
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* Boston, MA 02111-1307, USA.
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*/
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/**
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* SECTION:element-textoverlay
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* @see_also: #GstTextRender, #GstTextOverlay, #GstTimeOverlay, #GstSubParse
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*
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* This plugin renders text on top of a video stream. This can be either
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* static text or text from buffers received on the text sink pad, e.g.
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* as produced by the subparse element. If the text sink pad is not linked,
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* the text set via the "text" property will be rendered. If the text sink
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* pad is linked, text will be rendered as it is received on that pad,
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* honouring and matching the buffer timestamps of both input streams.
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*
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* The text can contain newline characters and text wrapping is enabled by
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* default.
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*
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* <refsect2>
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* <title>Example launch lines</title>
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* |[
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* gst-launch -v videotestsrc ! textoverlay text="Room A" valign=top halign=left ! xvimagesink
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* ]| Here is a simple pipeline that displays a static text in the top left
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* corner of the video picture
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* |[
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* gst-launch -v filesrc location=subtitles.srt ! subparse ! txt. videotestsrc ! timeoverlay ! textoverlay name=txt shaded-background=yes ! xvimagesink
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* ]| Here is another pipeline that displays subtitles from an .srt subtitle
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* file, centered at the bottom of the picture and with a rectangular shading
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* around the text in the background:
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* <para>
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* If you do not have such a subtitle file, create one looking like this
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* in a text editor:
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* |[
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* 1
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* 00:00:03,000 --> 00:00:05,000
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* Hello? (3-5s)
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*
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* 2
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* 00:00:08,000 --> 00:00:13,000
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* Yes, this is a subtitle. Don't
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* you like it? (8-13s)
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*
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* 3
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* 00:00:18,826 --> 00:01:02,886
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* Uh? What are you talking about?
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* I don't understand (18-62s)
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* ]|
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* One can also feed arbitrary live text into the element:
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* |[
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* gst-launch fdsrc fd=0 ! text/plain ! txt. videotestsrc ! \
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* textoverlay name=txt shaded-background=yes font-desc="Serif 40" wait-text=false ! \
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* xvimagesink
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* ]| This shows new text as entered on the terminal (stdin). This is not suited
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* for subtitles as the test overlay is not timed. Subtitles should use
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* timestamped formats. For the above use case one can also read the text from
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* the application as set the #GstTextOverlay:text property.
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* </para>
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* </refsect2>
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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 <gsttextoverlay.h>
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static GstStaticPadTemplate text_sink_template_factory =
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GST_STATIC_PAD_TEMPLATE ("text_sink",
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GST_PAD_SINK,
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GST_PAD_ALWAYS,
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GST_STATIC_CAPS ("text/x-pango-markup; text/plain")
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);
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G_DEFINE_TYPE (GstTextOverlay, gst_text_overlay, GST_TYPE_BASE_TEXT_OVERLAY);
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static void
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gst_text_overlay_class_init (GstTextOverlayClass * klass)
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{
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GstElementClass *element_class = (GstElementClass *) klass;
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gst_element_class_add_pad_template (element_class,
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gst_static_pad_template_get (&text_sink_template_factory));
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gst_element_class_set_details_simple (element_class, "Text overlay",
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"Filter/Editor/Video",
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"Adds text strings on top of a video buffer",
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"David Schleef <ds@schleef.org>, " "Zeeshan Ali <zeeshan.ali@nokia.com>");
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}
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static void
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gst_text_overlay_init (GstTextOverlay * overlay)
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{
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}
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