Add basic TTML support

This is meant to serve as a base for our Outreachy student's project:
https://wiki.gnome.org/Outreachy/2015/MayAugust#VideoLAN
refs #9396

NEWS

@@ -35,6 +35,7 @@ Decoder:
  * Rewrite WPL playlists and add ZPL playlists support (Zune)
  * Support TDSC, Canopus HQX
  * Support HEVC hardware decoding on Windows, using DxVA2
+ * Basic TTML subtitles support
 
 Demuxers:
  * Support HD-DVD .evo (H.264, VC-1, MPEG-2, PCM, AC-3, E-AC3, MLP, DTS)

modules/MODULES_LIST

@@ -368,6 +368,7 @@ $Id$
  * stream_out_transcode: audio & video transcoder
  * subsdec: a codec to output textual subtitles
  * subsdelay: subtitles delay filter
+ * substtml: TTML subtitles decoder
  * substx3g: tx3g styled subtitles decoder
  * subsusf: a demuxer for USF subtitles
  * subtitle: a demuxer for subtitle files
@@ -388,6 +389,7 @@ $Id$
  * trivial_channel_mixer: Simple channel mixer plugin
  * ts: MPEG-TS demuxer
  * tta: Lossless True Audio parser
+ * ttml: a TTML subtitles demuxer
  * twolame: a mp1 mp2 audio encoder based on twolame
  * ty: TY demuxer
  * udev: udev probing module

modules/codec/Makefile.am

@@ -198,6 +198,9 @@ codec_LTLIBRARIES += libsubsdec_plugin.la
 libsubsusf_plugin_la_SOURCES = codec/subsusf.c
 codec_LTLIBRARIES += libsubsusf_plugin.la
 
+libsubsttml_plugin_la_SOURCES = codec/substtml.c
+codec_LTLIBRARIES += libsubsttml_plugin.la
+
 libsvcdsub_plugin_la_SOURCES = codec/svcdsub.c
 codec_LTLIBRARIES += libsvcdsub_plugin.la
 

modules/codec/substtml.c

+/*****************************************************************************
+ * substtml.c : TTML subtitles decoder
+ *****************************************************************************
+ * Copyright (C) 2015 VLC authors and VideoLAN
+ *
+ * Authors: Hugo Beauzée-Luyssen <hugo@beauzee.fr>
+ *          Sushma Reddy <sushma.reddy@research.iiit.ac.in>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation; either version 2.1 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
+ *****************************************************************************/
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+#include <vlc_common.h>
+#include <vlc_plugin.h>
+#include <vlc_modules.h>
+#include <vlc_codec.h>
+
+#include "substext.h"
+
+#define ALIGN_TEXT N_("Subtitle justification")
+#define ALIGN_LONGTEXT N_("Set the justification of subtitles")
+
+/*****************************************************************************
+ * Module descriptor.
+ *****************************************************************************/
+static int  OpenDecoder   ( vlc_object_t * );
+static void CloseDecoder  ( vlc_object_t * );
+
+vlc_module_begin ()
+    set_capability( "decoder", 10 )
+    set_shortname( N_("TTML decoder"))
+    set_description( N_("TTML subtitles decoder") )
+    set_callbacks( OpenDecoder, CloseDecoder )
+    set_category( CAT_INPUT )
+    set_subcategory( SUBCAT_INPUT_SCODEC )
+    add_integer( "ttml-align", 0, ALIGN_TEXT, ALIGN_LONGTEXT, false )
+vlc_module_end ();
+
+
+/*****************************************************************************
+ * Local prototypes
+ *****************************************************************************/
+
+struct decoder_sys_t
+{
+    int i_align;
+};
+
+static subpicture_t *ParseText( decoder_t *p_dec, block_t *p_block )
+{
+    decoder_sys_t *p_sys = p_dec->p_sys;
+    subpicture_t *p_spu = NULL;
+    char *psz_subtitle = NULL;
+
+    /* We cannot display a subpicture with no date */
+    if( p_block->i_pts <= VLC_TS_INVALID )
+    {
+        msg_Warn( p_dec, "subtitle without a date" );
+        return NULL;
+    }
+
+    /* Check validity of packet data */
+    /* An "empty" line containing only \0 can be used to force
+       and ephemer picture from the screen */
+
+    if( p_block->i_buffer < 1 )
+    {
+        msg_Warn( p_dec, "no subtitle data" );
+        return NULL;
+    }
+
+    psz_subtitle = malloc( p_block->i_buffer );
+    if ( unlikely( psz_subtitle == NULL ) )
+        return NULL;
+    memcpy( psz_subtitle, p_block->p_buffer, p_block->i_buffer );
+
+    /* Create the subpicture unit */
+    p_spu = decoder_NewSubpictureText( p_dec );
+    if( !p_spu )
+    {
+        free( psz_subtitle );
+        return NULL;
+    }
+    p_spu->i_start    = p_block->i_pts;
+    p_spu->i_stop     = p_block->i_pts + p_block->i_length;
+    p_spu->b_ephemer  = (p_block->i_length == 0);
+    p_spu->b_absolute = false;
+    subpicture_updater_sys_t *p_spu_sys = p_spu->updater.p_sys;
+
+    p_spu_sys->align = SUBPICTURE_ALIGN_BOTTOM | p_sys->i_align;
+    p_spu_sys->text  = psz_subtitle;
+
+    return p_spu;
+}
+
+/****************************************************************************
+ * DecodeBlock: the whole thing
+ ****************************************************************************/
+static subpicture_t *DecodeBlock( decoder_t *p_dec, block_t **pp_block )
+{
+    if( !pp_block || *pp_block == NULL )
+        return NULL;
+
+    block_t* p_block = *pp_block;
+    subpicture_t *p_spu = ParseText( p_dec, p_block );
+
+    block_Release( p_block );
+    *pp_block = NULL;
+
+    return p_spu;
+}
+
+/*****************************************************************************
+ * OpenDecoder: probe the decoder and return score
+ *****************************************************************************/
+static int OpenDecoder( vlc_object_t *p_this )
+{
+    decoder_t *p_dec = (decoder_t*)p_this;
+    decoder_sys_t *p_sys;
+
+    if ( p_dec->fmt_in.i_codec != VLC_CODEC_TTML )
+    {
+        return VLC_EGENERIC;
+    }
+
+    /* Allocate the memory needed to store the decoder's structure */
+    p_dec->p_sys = p_sys = calloc( 1, sizeof( *p_sys ) );
+    if( unlikely( p_sys == NULL ) )
+    {
+        return VLC_ENOMEM;
+    }
+
+    p_dec->pf_decode_sub = DecodeBlock;
+    p_dec->fmt_out.i_cat = SPU_ES;
+    p_sys->i_align = var_InheritInteger( p_dec, "ttml-align" );
+    return VLC_SUCCESS;
+}
+
+/*****************************************************************************
+ * CloseDecoder: clean up the decoder
+ *****************************************************************************/
+static void CloseDecoder( vlc_object_t *p_this )
+{
+    /* Cleanup here */
+    decoder_t *p_dec = (decoder_t *)p_this;
+    decoder_sys_t *p_sys = p_dec->p_sys;
+
+    free( p_sys );
+}
+

modules/demux/Makefile.am

@@ -340,4 +340,6 @@ libdash_plugin_la_LIBADD += -lz
 endif
 demux_LTLIBRARIES += libdash_plugin.la
 
+libttml_plugin_la_SOURCES = demux/ttml.c
+demux_LTLIBRARIES += libttml_plugin.la
 

po/POTFILES.in

@@ -411,6 +411,7 @@ modules/codec/svcdsub.c
 modules/codec/t140.c
 modules/codec/telx.c
 modules/codec/theora.c
+modules/codec/substtml.c
 modules/codec/twolame.c
 modules/codec/uleaddvaudio.c
 modules/codec/vorbis.c
@@ -524,6 +525,7 @@ modules/demux/smf.c
 modules/demux/stl.c
 modules/demux/subtitle.c
 modules/demux/tta.c
+modules/demux/ttml.c
 modules/demux/ty.c
 modules/demux/vc1.c
 modules/demux/vobsub.c