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gstreamer/subprojects/gst-plugins-base/ext/pango/gstbasetextoverlay.h
Jan Schmidt c668f6fc22 basetextoverlay: Don't miscalculate text running times 
When a new segment event arrives, it immediately updates
the current stored segment, which was used for calculating
the running time of the current text buffer for every
passing video frame. This means a segment that arrives
after the text buffer might get used to (mis)calculate
the running times subsequently.

Instead, calculate and store the right running time
using the current segment when storing the buffer. Later
the stored segment can get freely updated.

This fixes the case where pieces of video and text streams
are seamlessly concatenated and fed through the text overlay.
Previously, it could lead to the current text buffer suddenly
have a massive running time and blocking all further input.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/2802>
2022-08-12 12:08:18 +00:00

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/* GStreamer
* Copyright (C) <1999> Erik Walthinsen <omega@cse.ogi.edu>
* Copyright (C) <2003> David Schleef <ds@schleef.org>
* Copyright (C) <2006> Julien Moutte <julien@moutte.net>
* Copyright (C) <2006> Zeeshan Ali <zeeshan.ali@nokia.com>
* Copyright (C) <2006-2008> Tim-Philipp Müller <tim centricular net>
* Copyright (C) <2009> Young-Ho Cha <ganadist@gmail.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.
*/
#ifndef __GST_BASE_TEXT_OVERLAY_H__
#define __GST_BASE_TEXT_OVERLAY_H__
#include <gst/gst.h>
#include <gst/video/video.h>
#include <gst/video/video-overlay-composition.h>
#include <pango/pangocairo.h>
G_BEGIN_DECLS
#define GST_TYPE_BASE_TEXT_OVERLAY (gst_base_text_overlay_get_type())
#define GST_BASE_TEXT_OVERLAY(obj) (G_TYPE_CHECK_INSTANCE_CAST((obj),\
GST_TYPE_BASE_TEXT_OVERLAY, GstBaseTextOverlay))
#define GST_BASE_TEXT_OVERLAY_CLASS(klass) (G_TYPE_CHECK_CLASS_CAST((klass),\
GST_TYPE_BASE_TEXT_OVERLAY,GstBaseTextOverlayClass))
#define GST_BASE_TEXT_OVERLAY_GET_CLASS(obj) (G_TYPE_INSTANCE_GET_CLASS ((obj),\
GST_TYPE_BASE_TEXT_OVERLAY, GstBaseTextOverlayClass))
#define GST_IS_BASE_TEXT_OVERLAY(obj) (G_TYPE_CHECK_INSTANCE_TYPE((obj),\
GST_TYPE_BASE_TEXT_OVERLAY))
#define GST_IS_BASE_TEXT_OVERLAY_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE((klass),\
GST_TYPE_BASE_TEXT_OVERLAY))
typedef struct _GstBaseTextOverlay GstBaseTextOverlay;
typedef struct _GstBaseTextOverlayClass GstBaseTextOverlayClass;
/**
* GstBaseTextOverlayVAlign:
* @GST_BASE_TEXT_OVERLAY_VALIGN_BASELINE: draw text on the baseline
* @GST_BASE_TEXT_OVERLAY_VALIGN_BOTTOM: draw text on the bottom
* @GST_BASE_TEXT_OVERLAY_VALIGN_TOP: draw text on top
* @GST_BASE_TEXT_OVERLAY_VALIGN_POS: draw text according to the #GstBaseTextOverlay:ypos property
* @GST_BASE_TEXT_OVERLAY_VALIGN_CENTER: draw text vertically centered
*
* Vertical alignment of the text.
*/
typedef enum {
GST_BASE_TEXT_OVERLAY_VALIGN_BASELINE,
GST_BASE_TEXT_OVERLAY_VALIGN_BOTTOM,
GST_BASE_TEXT_OVERLAY_VALIGN_TOP,
GST_BASE_TEXT_OVERLAY_VALIGN_POS,
GST_BASE_TEXT_OVERLAY_VALIGN_CENTER,
GST_BASE_TEXT_OVERLAY_VALIGN_ABSOLUTE
} GstBaseTextOverlayVAlign;
/**
* GstBaseTextOverlayHAlign:
* @GST_BASE_TEXT_OVERLAY_HALIGN_LEFT: align text left
* @GST_BASE_TEXT_OVERLAY_HALIGN_CENTER: align text center
* @GST_BASE_TEXT_OVERLAY_HALIGN_RIGHT: align text right
* @GST_BASE_TEXT_OVERLAY_HALIGN_POS: position text according to the #GstBaseTextOverlay:xpos property
*
* Horizontal alignment of the text.
*/
/* FIXME 0.11: remove GST_BASE_TEXT_OVERLAY_HALIGN_UNUSED */
typedef enum {
GST_BASE_TEXT_OVERLAY_HALIGN_LEFT,
GST_BASE_TEXT_OVERLAY_HALIGN_CENTER,
GST_BASE_TEXT_OVERLAY_HALIGN_RIGHT,
GST_BASE_TEXT_OVERLAY_HALIGN_UNUSED,
GST_BASE_TEXT_OVERLAY_HALIGN_POS,
GST_BASE_TEXT_OVERLAY_HALIGN_ABSOLUTE
} GstBaseTextOverlayHAlign;
/**
* GstBaseTextOverlayWrapMode:
* @GST_BASE_TEXT_OVERLAY_WRAP_MODE_NONE: no wrapping
* @GST_BASE_TEXT_OVERLAY_WRAP_MODE_WORD: do word wrapping
* @GST_BASE_TEXT_OVERLAY_WRAP_MODE_CHAR: do char wrapping
* @GST_BASE_TEXT_OVERLAY_WRAP_MODE_WORD_CHAR: do word and char wrapping
*
* Whether to wrap the text and if so how.
*/
typedef enum {
GST_BASE_TEXT_OVERLAY_WRAP_MODE_NONE = -1,
GST_BASE_TEXT_OVERLAY_WRAP_MODE_WORD = PANGO_WRAP_WORD,
GST_BASE_TEXT_OVERLAY_WRAP_MODE_CHAR = PANGO_WRAP_CHAR,
GST_BASE_TEXT_OVERLAY_WRAP_MODE_WORD_CHAR = PANGO_WRAP_WORD_CHAR
} GstBaseTextOverlayWrapMode;
/**
* GstBaseTextOverlayLineAlign:
* @GST_BASE_TEXT_OVERLAY_LINE_ALIGN_LEFT: lines are left-aligned
* @GST_BASE_TEXT_OVERLAY_LINE_ALIGN_CENTER: lines are center-aligned
* @GST_BASE_TEXT_OVERLAY_LINE_ALIGN_RIGHT: lines are right-aligned
*
* Alignment of text lines relative to each other
*/
typedef enum {
GST_BASE_TEXT_OVERLAY_LINE_ALIGN_LEFT = PANGO_ALIGN_LEFT,
GST_BASE_TEXT_OVERLAY_LINE_ALIGN_CENTER = PANGO_ALIGN_CENTER,
GST_BASE_TEXT_OVERLAY_LINE_ALIGN_RIGHT = PANGO_ALIGN_RIGHT
} GstBaseTextOverlayLineAlign;
/**
* GstBaseTextOverlayScaleMode:
* @GST_BASE_TEXT_OVERLAY_SCALE_MODE_NONE: no compensation
* @GST_BASE_TEXT_OVERLAY_SCALE_MODE_PAR: compensate pixel-aspect-ratio scaling
* @GST_BASE_TEXT_OVERLAY_SCALE_MODE_DISPLAY: compensate for scaling to display (as determined by overlay allocation meta)
* @GST_BASE_TEXT_OVERLAY_SCALE_MODE_USER: compensate scaling set by #GstBaseTextOverlay:scale-pixel-aspect-ratio property
*
* Scale text to compensate for and avoid aspect distortion by subsequent
* scaling of video
*/
typedef enum {
GST_BASE_TEXT_OVERLAY_SCALE_MODE_NONE,
GST_BASE_TEXT_OVERLAY_SCALE_MODE_PAR,
GST_BASE_TEXT_OVERLAY_SCALE_MODE_DISPLAY,
GST_BASE_TEXT_OVERLAY_SCALE_MODE_USER
} GstBaseTextOverlayScaleMode;
/**
* GstBaseTextOverlay:
*
* Opaque textoverlay object structure
*/
struct _GstBaseTextOverlay {
GstElement element;
GstPad *video_sinkpad;
GstPad *text_sinkpad;
GstPad *srcpad;
PangoContext *pango_context;
GstSegment segment;
GstSegment text_segment;
GstBuffer *text_buffer;
GstClockTime text_buffer_running_time;
GstClockTime text_buffer_running_time_end;
gboolean text_linked;
gboolean video_flushing;
gboolean video_eos;
gboolean text_flushing;
gboolean text_eos;
GMutex lock;
GCond cond; /* to signal removal of a queued text
* buffer, arrival of a text buffer,
* a text segment update, or a change
* in status (e.g. shutdown, flushing) */
/* stream metrics */
GstVideoInfo info;
GstVideoFormat format;
gint width;
gint height;
/* properties */
gint xpad;
gint ypad;
gint deltax;
gint deltay;
gdouble xpos;
gdouble ypos;
gchar *default_text;
gboolean want_shading;
gboolean silent;
gboolean wait_text;
guint color, outline_color;
PangoLayout *layout;
gboolean auto_adjust_size;
gboolean draw_shadow;
gboolean draw_outline;
gint shading_value; /* for timeoverlay subclass */
gboolean use_vertical_render;
GstBaseTextOverlayVAlign valign;
GstBaseTextOverlayHAlign halign;
GstBaseTextOverlayWrapMode wrap_mode;
GstBaseTextOverlayLineAlign line_align;
GstBaseTextOverlayScaleMode scale_mode;
gint scale_par_n;
gint scale_par_d;
/* text pad format */
gboolean have_pango_markup;
/* rendering state */
gboolean need_render;
GstBuffer *text_image;
/* dimension relative to witch the render is done, this is the stream size
* or a portion of the window_size (adapted to aspect ratio) */
gint render_width;
gint render_height;
/* This is (render_width / width) uses to convert to stream scale */
gdouble render_scale;
/* dimension of text_image, the physical dimension */
guint text_width;
guint text_height;
/* position of rendering in image coordinates */
gint text_x;
gint text_y;
/* window dimension, reported in the composition meta params. This is set
* to stream width, height if missing */
gint window_width;
gint window_height;
gdouble shadow_offset;
gdouble outline_offset;
PangoRectangle ink_rect;
PangoRectangle logical_rect;
gboolean attach_compo_to_buffer;
GstVideoOverlayComposition *composition;
GstVideoOverlayComposition *upstream_composition;
};
struct _GstBaseTextOverlayClass {
GstElementClass parent_class;
gchar * (*get_text) (GstBaseTextOverlay *overlay, GstBuffer *video_frame);
};
GType gst_base_text_overlay_get_type(void) G_GNUC_CONST;
G_END_DECLS
#endif /* __GST_BASE_TEXT_OVERLAY_H */
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