gstreamer/ext/ttml/subtitle.c
Chris Bass 2863a55a89 ttml: Add support for IMSC 1.0.1 fillLineGap attribute
Strictly speaking, the TTML spec requires that text backgrounds extend
only to the font height of the related text, rather than to the vertical
distance between lines. The result of this is that there will typically
be vertical gaps between line backgrounds through which moving video can
be seen. Since this was unnacceptable to some content providers, v1.0.1
of the IMSC spec (which profiles TTML) adds a new attribute,
itts:fillLineGap[1], that allows content authors to specify that clients
should extend text backgrounds such that there are no gaps between
lines. This attribute is also going to be included in the next release
of EBU-TT-D.

This patch adds support for fillLineGap to ttmlparse and ttmlrender.

[1] https://www.w3.org/TR/ttml-imsc1.0.1/#itts-fillLineGap

https://bugzilla.gnome.org/show_bug.cgi?id=787071
2018-02-27 16:27:47 +02:00

320 lines
9.4 KiB
C

/* GStreamer
* Copyright (C) <2015> British Broadcasting Corporation
* Author: Chris Bass <dash@rd.bbc.co.uk>
*
* 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.
*/
/**
* SECTION:gstsubtitle
* @title: GstSubtitle
* @short_description: Library for describing sets of static subtitles.
*
* This library enables the description of static text scenes made up of a
* number of regions, which may contain a number of block and inline text
* elements. It is derived from the concepts and features defined in the Timed
* Text Markup Language 1 (TTML1), Second Edition
* (http://www.w3.org/TR/ttaf1-dfxp), and the EBU-TT-D profile of TTML1
* (https://tech.ebu.ch/files/live/sites/tech/files/shared/tech/tech3380.pdf).
*/
#include "subtitle.h"
/**
* gst_subtitle_style_set_free:
* @style_set: A #GstSubtitleStyleSet.
*
* Free @style_set and its associated memory.
*/
static void
_gst_subtitle_style_set_free (GstSubtitleStyleSet * style_set)
{
g_return_if_fail (style_set != NULL);
g_free (style_set->font_family);
g_slice_free (GstSubtitleStyleSet, style_set);
}
GST_DEFINE_MINI_OBJECT_TYPE (GstSubtitleStyleSet, gst_subtitle_style_set);
/**
* gst_subtitle_style_set_new:
*
* Create a new #GstSubtitleStyleSet with default values for all properties.
*
* Returns: (transfer full): A newly-allocated #GstSubtitleStyleSet.
*/
GstSubtitleStyleSet *
gst_subtitle_style_set_new (void)
{
GstSubtitleStyleSet *ret = g_slice_new0 (GstSubtitleStyleSet);
GstSubtitleColor white = { 255, 255, 255, 255 };
GstSubtitleColor transparent = { 0, 0, 0, 0 };
gst_mini_object_init (GST_MINI_OBJECT_CAST (ret), 0,
gst_subtitle_style_set_get_type (), NULL, NULL,
(GstMiniObjectFreeFunction) _gst_subtitle_style_set_free);
ret->font_family = g_strdup ("default");
ret->font_size = 1.0;
ret->line_height = -1;
ret->color = white;
ret->background_color = transparent;
ret->line_padding = 0.0;
ret->origin_x = ret->origin_y = 0.0;
ret->extent_w = ret->extent_h = 0.0;
ret->padding_start = ret->padding_end
= ret->padding_before = ret->padding_after = 0.0;
ret->fill_line_gap = FALSE;
return ret;
}
static void
_gst_subtitle_element_free (GstSubtitleElement * element)
{
g_return_if_fail (element != NULL);
gst_subtitle_style_set_unref (element->style_set);
g_slice_free (GstSubtitleElement, element);
}
GST_DEFINE_MINI_OBJECT_TYPE (GstSubtitleElement, gst_subtitle_element);
/**
* gst_subtitle_element_new:
* @style_set: (transfer full): A #GstSubtitleStyleSet that defines the styling
* and layout associated with this inline text element.
* @text_index: The index within a #GstBuffer of the #GstMemory that contains
* the text of this inline text element.
*
* Allocates a new #GstSubtitleElement.
*
* Returns: (transfer full): A newly-allocated #GstSubtitleElement. Unref
* with gst_subtitle_element_unref() when no longer needed.
*/
GstSubtitleElement *
gst_subtitle_element_new (GstSubtitleStyleSet * style_set,
guint text_index, gboolean suppress_whitespace)
{
GstSubtitleElement *element;
g_return_val_if_fail (style_set != NULL, NULL);
element = g_slice_new0 (GstSubtitleElement);
gst_mini_object_init (GST_MINI_OBJECT_CAST (element), 0,
gst_subtitle_element_get_type (), NULL, NULL,
(GstMiniObjectFreeFunction) _gst_subtitle_element_free);
element->style_set = style_set;
element->text_index = text_index;
element->suppress_whitespace = suppress_whitespace;
return element;
}
static void
_gst_subtitle_block_free (GstSubtitleBlock * block)
{
g_return_if_fail (block != NULL);
gst_subtitle_style_set_unref (block->style_set);
g_ptr_array_unref (block->elements);
g_slice_free (GstSubtitleBlock, block);
}
GST_DEFINE_MINI_OBJECT_TYPE (GstSubtitleBlock, gst_subtitle_block);
/**
* gst_subtitle_block_new:
* @style_set: (transfer full): A #GstSubtitleStyleSet that defines the styling
* and layout associated with this block of text elements.
*
* Allocates a new #GstSubtitleBlock.
*
* Returns: (transfer full): A newly-allocated #GstSubtitleBlock. Unref
* with gst_subtitle_block_unref() when no longer needed.
*/
GstSubtitleBlock *
gst_subtitle_block_new (GstSubtitleStyleSet * style_set)
{
GstSubtitleBlock *block;
g_return_val_if_fail (style_set != NULL, NULL);
block = g_slice_new0 (GstSubtitleBlock);
gst_mini_object_init (GST_MINI_OBJECT_CAST (block), 0,
gst_subtitle_block_get_type (), NULL, NULL,
(GstMiniObjectFreeFunction) _gst_subtitle_block_free);
block->style_set = style_set;
block->elements = g_ptr_array_new_with_free_func (
(GDestroyNotify) gst_subtitle_element_unref);
return block;
}
/**
* gst_subtitle_block_add_element:
* @block: A #GstSubtitleBlock.
* @element: (transfer full): A #GstSubtitleElement to add.
*
* Adds a #GstSubtitleElement to @block.
*/
void
gst_subtitle_block_add_element (GstSubtitleBlock * block,
GstSubtitleElement * element)
{
g_return_if_fail (block != NULL);
g_return_if_fail (element != NULL);
g_ptr_array_add (block->elements, element);
}
/**
* gst_subtitle_block_get_element_count:
* @block: A #GstSubtitleBlock.
*
* Returns: The number of #GstSubtitleElements in @block.
*/
guint
gst_subtitle_block_get_element_count (const GstSubtitleBlock * block)
{
g_return_val_if_fail (block != NULL, 0);
return block->elements->len;
}
/**
* gst_subtitle_block_get_element:
* @block: A #GstSubtitleBlock.
* @index: Index of the element to get.
*
* Gets the #GstSubtitleElement at @index in the array of elements held by
* @block.
*
* Returns: (transfer none): The #GstSubtitleElement at @index in the array of
* elements held by @block, or %NULL if @index is out-of-bounds. The
* function does not return a reference; the caller should obtain a reference
* using gst_subtitle_element_ref(), if needed.
*/
GstSubtitleElement *
gst_subtitle_block_get_element (const GstSubtitleBlock * block, guint index)
{
g_return_val_if_fail (block != NULL, NULL);
if (index >= block->elements->len)
return NULL;
else
return g_ptr_array_index (block->elements, index);
}
static void
_gst_subtitle_region_free (GstSubtitleRegion * region)
{
g_return_if_fail (region != NULL);
gst_subtitle_style_set_unref (region->style_set);
g_ptr_array_unref (region->blocks);
g_slice_free (GstSubtitleRegion, region);
}
GST_DEFINE_MINI_OBJECT_TYPE (GstSubtitleRegion, gst_subtitle_region);
/**
* gst_subtitle_region_new:
* @style_set: (transfer full): A #GstSubtitleStyleSet that defines the styling
* and layout associated with this region.
*
* Allocates a new #GstSubtitleRegion.
*
* Returns: (transfer full): A newly-allocated #GstSubtitleRegion. Unref
* with gst_subtitle_region_unref() when no longer needed.
*/
GstSubtitleRegion *
gst_subtitle_region_new (GstSubtitleStyleSet * style_set)
{
GstSubtitleRegion *region;
g_return_val_if_fail (style_set != NULL, NULL);
region = g_slice_new0 (GstSubtitleRegion);
gst_mini_object_init (GST_MINI_OBJECT_CAST (region), 0,
gst_subtitle_region_get_type (), NULL, NULL,
(GstMiniObjectFreeFunction) _gst_subtitle_region_free);
region->style_set = style_set;
region->blocks = g_ptr_array_new_with_free_func (
(GDestroyNotify) gst_subtitle_block_unref);
return region;
}
/**
* gst_subtitle_region_add_block:
* @region: A #GstSubtitleRegion.
* @block: (transfer full): A #GstSubtitleBlock which should be added
* to @region's array of blocks.
*
* Adds a #GstSubtitleBlock to the end of the array of blocks held by @region.
* @region will take ownership of @block, and will unref it when @region
* is freed.
*/
void
gst_subtitle_region_add_block (GstSubtitleRegion * region,
GstSubtitleBlock * block)
{
g_return_if_fail (region != NULL);
g_return_if_fail (block != NULL);
g_ptr_array_add (region->blocks, block);
}
/**
* gst_subtitle_region_get_block_count:
* @region: A #GstSubtitleRegion.
*
* Returns: The number of blocks in @region.
*/
guint
gst_subtitle_region_get_block_count (const GstSubtitleRegion * region)
{
g_return_val_if_fail (region != NULL, 0);
return region->blocks->len;
}
/**
* gst_subtitle_region_get_block:
* @region: A #GstSubtitleRegion.
* @index: Index of the block to get.
*
* Gets the block at @index in the array of blocks held by @region.
*
* Returns: (transfer none): The #GstSubtitleBlock at @index in the array of
* blocks held by @region, or %NULL if @index is out-of-bounds. The
* function does not return a reference; the caller should obtain a reference
* using gst_subtitle_block_ref(), if needed.
*/
const GstSubtitleBlock *
gst_subtitle_region_get_block (const GstSubtitleRegion * region, guint index)
{
g_return_val_if_fail (region != NULL, NULL);
if (index >= region->blocks->len)
return NULL;
else
return g_ptr_array_index (region->blocks, index);
}