16
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/* GStreamer AVI GAB2 subtitle parser
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* Copyright (C) <2007> Thijs Vermeir <thijsvermeir@gmail.com>
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* Copyright (C) <2007> Tim-Philipp Müller <tim centricular net>
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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-avisubtitle
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*
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* <refsect2>
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* <para>
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* Parses the subtitle stream from an avi file.
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* </para>
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* <title>Example launch line</title>
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* <para>
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* <programlisting>
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* gst-launch filesrc location=subtitle.avi ! avidemux name=demux ! queue ! avisubtitle ! subparse ! textoverlay name=overlay ! ffmpegcolorspace ! autovideosink demux. ! queue ! decodebin ! overlay.
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* </programlisting>
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* This plays an avi file with a video and subtitle stream.
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* </para>
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* </refsect2>
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*
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* Last reviewed on 2008-02-01
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*/
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/* example of a subtitle chunk in an avi file
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* 00000000: 47 41 42 32 00 02 00 10 00 00 00 45 00 6e 00 67 GAB2.......E.n.g
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* 00000010: 00 6c 00 69 00 73 00 68 00 00 00 04 00 8e 00 00 .l.i.s.h........
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* 00000020: 00 ef bb bf 31 0d 0a 30 30 3a 30 30 3a 30 30 2c ....1..00:00:00,
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* 00000030: 31 30 30 20 2d 2d 3e 20 30 30 3a 30 30 3a 30 32 100 --> 00:00:02
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* 00000040: 2c 30 30 30 0d 0a 3c 62 3e 41 6e 20 55 54 46 38 ,000..<b>An UTF8
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* 00000050: 20 53 75 62 74 69 74 6c 65 20 77 69 74 68 20 42 Subtitle with B
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* 00000060: 4f 4d 3c 2f 62 3e 0d 0a 0d 0a 32 0d 0a 30 30 3a OM</b>....2..00:
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* 00000070: 30 30 3a 30 32 2c 31 30 30 20 2d 2d 3e 20 30 30 00:02,100 --> 00
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* 00000080: 3a 30 30 3a 30 34 2c 30 30 30 0d 0a 53 6f 6d 65 :00:04,000..Some
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* 00000090: 74 68 69 6e 67 20 6e 6f 6e 41 53 43 49 49 20 2d thing nonASCII -
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* 000000a0: 20 c2 b5 c3 b6 c3 a4 c3 bc c3 9f 0d 0a 0d 0a ..............
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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 <string.h>
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#include "gstavisubtitle.h"
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GST_DEBUG_CATEGORY_STATIC (avisubtitle_debug);
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#define GST_CAT_DEFAULT avisubtitle_debug
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static GstStaticPadTemplate sink_template = GST_STATIC_PAD_TEMPLATE ("sink",
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GST_PAD_SINK,
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67 |
GST_PAD_ALWAYS,
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68 |
GST_STATIC_CAPS ("application/x-subtitle-avi")
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69 |
);
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70 |
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71 |
static GstStaticPadTemplate src_template = GST_STATIC_PAD_TEMPLATE ("src",
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GST_PAD_SRC,
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73 |
GST_PAD_ALWAYS,
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74 |
GST_STATIC_CAPS ("application/x-subtitle")
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);
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77 |
static void gst_avi_subtitle_title_tag (GstAviSubtitle * sub, gchar * title);
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78 |
static GstFlowReturn gst_avi_subtitle_chain (GstPad * pad, GstBuffer * buffer);
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79 |
static GstStateChangeReturn gst_avi_subtitle_change_state (GstElement * element,
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GstStateChange transition);
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static gboolean gst_avi_subtitle_send_event (GstElement * element,
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GstEvent * event);
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84 |
GST_BOILERPLATE (GstAviSubtitle, gst_avi_subtitle, GstElement,
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GST_TYPE_ELEMENT);
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87 |
#define IS_BOM_UTF8(data) ((GST_READ_UINT32_BE(data) >> 8) == 0xEFBBBF)
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88 |
#define IS_BOM_UTF16_BE(data) (GST_READ_UINT16_BE(data) == 0xFEFF)
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#define IS_BOM_UTF16_LE(data) (GST_READ_UINT16_LE(data) == 0xFEFF)
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90 |
#define IS_BOM_UTF32_BE(data) (GST_READ_UINT32_BE(data) == 0xFEFF)
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#define IS_BOM_UTF32_LE(data) (GST_READ_UINT32_LE(data) == 0xFEFF)
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93 |
static GstBuffer *
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gst_avi_subtitle_extract_file (GstAviSubtitle * sub, GstBuffer * buffer,
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guint offset, guint len)
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96 |
{
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const gchar *input_enc = NULL;
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98 |
GstBuffer *ret = NULL;
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gchar *data;
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100 |
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101 |
data = (gchar *) GST_BUFFER_DATA (buffer) + offset;
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if (len >= (3 + 1) && IS_BOM_UTF8 (data) &&
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104 |
g_utf8_validate (data + 3, len - 3, NULL)) {
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105 |
ret = gst_buffer_create_sub (buffer, offset + 3, len - 3);
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106 |
} else if (len >= 2 && IS_BOM_UTF16_BE (data)) {
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107 |
input_enc = "UTF-16BE";
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108 |
data += 2;
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109 |
len -= 2;
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110 |
} else if (len >= 2 && IS_BOM_UTF16_LE (data)) {
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input_enc = "UTF-16LE";
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data += 2;
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len -= 2;
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} else if (len >= 4 && IS_BOM_UTF32_BE (data)) {
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input_enc = "UTF-32BE";
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data += 4;
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len -= 4;
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118 |
} else if (len >= 4 && IS_BOM_UTF32_LE (data)) {
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input_enc = "UTF-32LE";
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data += 4;
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len -= 4;
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122 |
} else if (g_utf8_validate (data, len, NULL)) {
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/* not specified, check if it's UTF-8 */
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ret = gst_buffer_create_sub (buffer, offset, len);
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} else {
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126 |
/* we could fall back to gst_tag_freeform_to_utf8() here */
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127 |
GST_WARNING_OBJECT (sub, "unspecified encoding, and not UTF-8");
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return NULL;
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129 |
}
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g_return_val_if_fail (ret != NULL || input_enc != NULL, NULL);
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132 |
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133 |
if (input_enc) {
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GError *err = NULL;
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135 |
gchar *utf8;
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136 |
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137 |
GST_DEBUG_OBJECT (sub, "converting subtitles from %s to UTF-8", input_enc);
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138 |
utf8 = g_convert (data, len, "UTF-8", input_enc, NULL, NULL, &err);
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139 |
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140 |
if (err != NULL) {
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141 |
GST_WARNING_OBJECT (sub, "conversion to UTF-8 failed : %s", err->message);
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142 |
g_error_free (err);
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143 |
return NULL;
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144 |
}
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145 |
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146 |
ret = gst_buffer_new ();
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147 |
GST_BUFFER_DATA (ret) = (guint8 *) utf8;
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148 |
GST_BUFFER_MALLOCDATA (ret) = (guint8 *) utf8;
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149 |
GST_BUFFER_SIZE (ret) = strlen (utf8);
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GST_BUFFER_OFFSET (ret) = 0;
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}
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152 |
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GST_BUFFER_CAPS (ret) = gst_caps_new_simple ("application/x-subtitle", NULL);
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return ret;
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}
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/**
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* gst_avi_subtitle_title_tag:
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* @sub: subtitle element
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* @title: the title of this subtitle stream
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*
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* Send an event to the srcpad of the @sub element with the title
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* of the subtitle stream as a GST_TAG_TITLE
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*/
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static void
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gst_avi_subtitle_title_tag (GstAviSubtitle * sub, gchar * title)
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{
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GstTagList *temp_list = gst_tag_list_new ();
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gst_tag_list_add (temp_list, GST_TAG_MERGE_APPEND, GST_TAG_TITLE, title,
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NULL);
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gst_pad_push_event (sub->src, gst_event_new_tag (temp_list));
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}
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static GstFlowReturn
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gst_avi_subtitle_parse_gab2_chunk (GstAviSubtitle * sub, GstBuffer * buf)
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{
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const guint8 *data;
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gchar *name_utf8;
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guint name_length;
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guint file_length;
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guint size;
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data = GST_BUFFER_DATA (buf);
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size = GST_BUFFER_SIZE (buf);
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/* check the magic word "GAB2\0", and the next word must be 2 */
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if (size < 12 || memcmp (data, "GAB2\0\2\0", 5 + 2) != 0)
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goto wrong_magic_word;
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/* read 'name' of subtitle */
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name_length = GST_READ_UINT32_LE (data + 5 + 2);
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GST_LOG_OBJECT (sub, "length of name: %u", name_length);
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if (size <= 17 + name_length)
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goto wrong_name_length;
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196 |
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name_utf8 = g_convert ((gchar *) data + 11, name_length, "UTF-8", "UTF-16LE",
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NULL, NULL, NULL);
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if (name_utf8) {
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GST_LOG_OBJECT (sub, "subtitle name: %s", name_utf8);
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gst_avi_subtitle_title_tag (sub, name_utf8);
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g_free (name_utf8);
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}
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205 |
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206 |
/* next word must be 4 */
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207 |
if (GST_READ_UINT16_LE (data + 11 + name_length) != 0x4)
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goto wrong_fixed_word_2;
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209 |
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210 |
file_length = GST_READ_UINT32_LE (data + 13 + name_length);
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211 |
GST_LOG_OBJECT (sub, "length srt/ssa file: %u", file_length);
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212 |
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213 |
if (size < (17 + name_length + file_length))
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214 |
goto wrong_total_length;
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215 |
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216 |
/* store this, so we can send it again after a seek; note that we shouldn't
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217 |
* assume all the remaining data in the chunk is subtitle data, there may
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218 |
* be padding at the end for some reason, so only parse file_length bytes */
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219 |
sub->subfile =
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220 |
gst_avi_subtitle_extract_file (sub, buf, 17 + name_length, file_length);
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221 |
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222 |
if (sub->subfile == NULL)
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goto extract_failed;
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224 |
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225 |
return GST_FLOW_OK;
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226 |
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227 |
/* ERRORS */
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228 |
wrong_magic_word:
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229 |
{
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230 |
GST_ELEMENT_ERROR (sub, STREAM, DECODE, (NULL), ("Wrong magic word"));
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231 |
return GST_FLOW_ERROR;
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232 |
}
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233 |
wrong_name_length:
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234 |
{
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235 |
GST_ELEMENT_ERROR (sub, STREAM, DECODE, (NULL),
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236 |
("name doesn't fit in buffer (%d < %d)", size, 17 + name_length));
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237 |
return GST_FLOW_ERROR;
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238 |
}
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239 |
wrong_fixed_word_2:
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240 |
{
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241 |
GST_ELEMENT_ERROR (sub, STREAM, DECODE, (NULL),
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242 |
("wrong fixed word: expected %u, got %u", 4,
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243 |
GST_READ_UINT16_LE (data + 11 + name_length)));
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244 |
return GST_FLOW_ERROR;
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245 |
}
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246 |
wrong_total_length:
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247 |
{
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|
248 |
GST_ELEMENT_ERROR (sub, STREAM, DECODE, (NULL),
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|
249 |
("buffer size is wrong: need %d bytes, have %d bytes",
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250 |
17 + name_length + file_length, size));
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251 |
return GST_FLOW_ERROR;
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252 |
}
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253 |
extract_failed:
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254 |
{
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|
255 |
GST_ELEMENT_ERROR (sub, STREAM, DECODE, (NULL),
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256 |
("could not extract subtitles"));
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|
257 |
return GST_FLOW_ERROR;
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|
258 |
}
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|
259 |
}
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|
260 |
|
|
261 |
static GstFlowReturn
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262 |
gst_avi_subtitle_chain (GstPad * pad, GstBuffer * buffer)
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|
263 |
{
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|
264 |
GstAviSubtitle *sub = GST_AVI_SUBTITLE (GST_PAD_PARENT (pad));
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265 |
GstFlowReturn ret;
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|
266 |
|
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267 |
if (sub->subfile != NULL) {
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268 |
GST_WARNING_OBJECT (sub, "Got more buffers than expected, dropping");
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|
269 |
ret = GST_FLOW_UNEXPECTED;
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|
270 |
goto done;
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|
271 |
}
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|
272 |
|
|
273 |
/* we expect exactly one buffer with the whole srt/ssa file in it */
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|
274 |
ret = gst_avi_subtitle_parse_gab2_chunk (sub, buffer);
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|
275 |
if (ret != GST_FLOW_OK)
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|
276 |
goto done;
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|
277 |
|
|
278 |
/* now push the subtitle data downstream */
|
|
279 |
ret = gst_pad_push (sub->src, gst_buffer_ref (sub->subfile));
|
|
280 |
|
|
281 |
done:
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|
282 |
|
|
283 |
gst_buffer_unref (buffer);
|
|
284 |
return ret;
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|
285 |
}
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|
286 |
|
|
287 |
static gboolean
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|
288 |
gst_avi_subtitle_send_event (GstElement * element, GstEvent * event)
|
|
289 |
{
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|
290 |
GstAviSubtitle *avisubtitle = GST_AVI_SUBTITLE (element);
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|
291 |
gboolean ret = FALSE;
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|
292 |
|
|
293 |
if (GST_EVENT_TYPE (event) == GST_EVENT_SEEK) {
|
|
294 |
if (avisubtitle->subfile) {
|
|
295 |
if (gst_pad_push (avisubtitle->src,
|
|
296 |
gst_buffer_ref (avisubtitle->subfile)) == GST_FLOW_OK)
|
|
297 |
ret = TRUE;
|
|
298 |
}
|
|
299 |
}
|
|
300 |
gst_event_unref (event);
|
|
301 |
return ret;
|
|
302 |
}
|
|
303 |
|
|
304 |
static void
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|
305 |
gst_avi_subtitle_base_init (gpointer klass)
|
|
306 |
{
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|
307 |
GstElementClass *element_class = GST_ELEMENT_CLASS (klass);
|
|
308 |
|
|
309 |
GST_DEBUG_CATEGORY_INIT (avisubtitle_debug, "avisubtitle", 0,
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|
310 |
"parse avi subtitle stream");
|
|
311 |
|
|
312 |
gst_element_class_add_pad_template (element_class,
|
|
313 |
gst_static_pad_template_get (&sink_template));
|
|
314 |
gst_element_class_add_pad_template (element_class,
|
|
315 |
gst_static_pad_template_get (&src_template));
|
|
316 |
|
|
317 |
gst_element_class_set_details_simple (element_class,
|
|
318 |
"Avi subtitle parser", "Codec/Parser/Subtitle",
|
|
319 |
"Parse avi subtitle stream", "Thijs Vermeir <thijsvermeir@gmail.com>");
|
|
320 |
}
|
|
321 |
|
|
322 |
static void
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|
323 |
gst_avi_subtitle_class_init (GstAviSubtitleClass * klass)
|
|
324 |
{
|
|
325 |
GstElementClass *gstelement_class = (GstElementClass *) klass;
|
|
326 |
|
|
327 |
gstelement_class->change_state =
|
|
328 |
GST_DEBUG_FUNCPTR (gst_avi_subtitle_change_state);
|
|
329 |
gstelement_class->send_event =
|
|
330 |
GST_DEBUG_FUNCPTR (gst_avi_subtitle_send_event);
|
|
331 |
}
|
|
332 |
|
|
333 |
static void
|
|
334 |
gst_avi_subtitle_init (GstAviSubtitle * self, GstAviSubtitleClass * klass)
|
|
335 |
{
|
|
336 |
self->src = gst_pad_new_from_static_template (&src_template, "src");
|
|
337 |
gst_element_add_pad (GST_ELEMENT (self), self->src);
|
|
338 |
|
|
339 |
self->sink = gst_pad_new_from_static_template (&sink_template, "sink");
|
|
340 |
gst_pad_set_chain_function (self->sink,
|
|
341 |
GST_DEBUG_FUNCPTR (gst_avi_subtitle_chain));
|
|
342 |
gst_element_add_pad (GST_ELEMENT (self), self->sink);
|
|
343 |
|
|
344 |
self->subfile = NULL;
|
|
345 |
}
|
|
346 |
|
|
347 |
static GstStateChangeReturn
|
|
348 |
gst_avi_subtitle_change_state (GstElement * element, GstStateChange transition)
|
|
349 |
{
|
|
350 |
GstStateChangeReturn ret;
|
|
351 |
GstAviSubtitle *sub = GST_AVI_SUBTITLE (element);
|
|
352 |
|
|
353 |
switch (transition) {
|
|
354 |
case GST_STATE_CHANGE_NULL_TO_READY:
|
|
355 |
case GST_STATE_CHANGE_READY_TO_PAUSED:
|
|
356 |
default:
|
|
357 |
break;
|
|
358 |
}
|
|
359 |
|
|
360 |
ret = GST_ELEMENT_CLASS (parent_class)->change_state (element, transition);
|
|
361 |
if (ret == GST_STATE_CHANGE_FAILURE)
|
|
362 |
return ret;
|
|
363 |
|
|
364 |
switch (transition) {
|
|
365 |
case GST_STATE_CHANGE_PAUSED_TO_READY:
|
|
366 |
if (sub->subfile) {
|
|
367 |
gst_buffer_unref (sub->subfile);
|
|
368 |
sub->subfile = NULL;
|
|
369 |
}
|
|
370 |
break;
|
|
371 |
default:
|
|
372 |
break;
|
|
373 |
}
|
|
374 |
|
|
375 |
return ret;
|
|
376 |
}
|