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Diffstat (limited to 'gst/avi/gstavisubtitle.c')
| -rw-r--r-- | gst/avi/gstavisubtitle.c | 383 |
1 files changed, 383 insertions, 0 deletions
diff --git a/gst/avi/gstavisubtitle.c b/gst/avi/gstavisubtitle.c new file mode 100644 index 0000000..ad1cd90 --- /dev/null +++ b/gst/avi/gstavisubtitle.c @@ -0,0 +1,383 @@ +/* GStreamer AVI GAB2 subtitle parser + * Copyright (C) <2007> Thijs Vermeir <thijsvermeir@gmail.com> + * Copyright (C) <2007> Tim-Philipp Müller <tim centricular net> + * + * 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., 59 Temple Place - Suite 330, + * Boston, MA 02111-1307, USA. + */ + +/** + * SECTION:element-avisubtitle + * + * <refsect2> + * <para> + * Parses the subtitle stream from an avi file. + * </para> + * <title>Example launch line</title> + * <para> + * <programlisting> + * gst-launch filesrc location=subtitle.avi ! avidemux name=demux ! queue ! avisubtitle ! subparse ! textoverlay name=overlay ! ffmpegcolorspace ! autovideosink demux. ! queue ! decodebin ! overlay. + * </programlisting> + * This plays an avi file with a video and subtitle stream. + * </para> + * </refsect2> + * + * Last reviewed on 2008-02-01 + */ + +/* example of a subtitle chunk in an avi file + * 00000000: 47 41 42 32 00 02 00 10 00 00 00 45 00 6e 00 67 GAB2.......E.n.g + * 00000010: 00 6c 00 69 00 73 00 68 00 00 00 04 00 8e 00 00 .l.i.s.h........ + * 00000020: 00 ef bb bf 31 0d 0a 30 30 3a 30 30 3a 30 30 2c ....1..00:00:00, + * 00000030: 31 30 30 20 2d 2d 3e 20 30 30 3a 30 30 3a 30 32 100 --> 00:00:02 + * 00000040: 2c 30 30 30 0d 0a 3c 62 3e 41 6e 20 55 54 46 38 ,000..<b>An UTF8 + * 00000050: 20 53 75 62 74 69 74 6c 65 20 77 69 74 68 20 42 Subtitle with B + * 00000060: 4f 4d 3c 2f 62 3e 0d 0a 0d 0a 32 0d 0a 30 30 3a OM</b>....2..00: + * 00000070: 30 30 3a 30 32 2c 31 30 30 20 2d 2d 3e 20 30 30 00:02,100 --> 00 + * 00000080: 3a 30 30 3a 30 34 2c 30 30 30 0d 0a 53 6f 6d 65 :00:04,000..Some + * 00000090: 74 68 69 6e 67 20 6e 6f 6e 41 53 43 49 49 20 2d thing nonASCII - + * 000000a0: 20 c2 b5 c3 b6 c3 a4 c3 bc c3 9f 0d 0a 0d 0a .............. + */ + +#ifdef HAVE_CONFIG_H +#include "config.h" +#endif + +#include <string.h> + +#include "gstavisubtitle.h" + +GST_DEBUG_CATEGORY_STATIC (avisubtitle_debug); +#define GST_CAT_DEFAULT avisubtitle_debug + +static GstStaticPadTemplate sink_template = GST_STATIC_PAD_TEMPLATE ("sink", + GST_PAD_SINK, + GST_PAD_ALWAYS, + GST_STATIC_CAPS ("application/x-subtitle-avi") + ); + +static GstStaticPadTemplate src_template = GST_STATIC_PAD_TEMPLATE ("src", + GST_PAD_SRC, + GST_PAD_ALWAYS, + GST_STATIC_CAPS ("application/x-subtitle") + ); + +static void gst_avi_subtitle_title_tag (GstAviSubtitle * sub, gchar * title); +static GstFlowReturn gst_avi_subtitle_chain (GstPad * pad, GstBuffer * buffer); +static GstStateChangeReturn gst_avi_subtitle_change_state (GstElement * element, + GstStateChange transition); +static gboolean gst_avi_subtitle_send_event (GstElement * element, + GstEvent * event); + +GST_BOILERPLATE (GstAviSubtitle, gst_avi_subtitle, GstElement, + GST_TYPE_ELEMENT); + +#define IS_BOM_UTF8(data) ((GST_READ_UINT32_BE(data) >> 8) == 0xEFBBBF) +#define IS_BOM_UTF16_BE(data) (GST_READ_UINT16_BE(data) == 0xFEFF) +#define IS_BOM_UTF16_LE(data) (GST_READ_UINT16_LE(data) == 0xFEFF) +#define IS_BOM_UTF32_BE(data) (GST_READ_UINT32_BE(data) == 0xFEFF) +#define IS_BOM_UTF32_LE(data) (GST_READ_UINT32_LE(data) == 0xFEFF) + +static GstBuffer * +gst_avi_subtitle_extract_file (GstAviSubtitle * sub, GstBuffer * buffer, + guint offset, guint len) +{ + const gchar *input_enc = NULL; + GstBuffer *ret = NULL; + gchar *data; + + data = (gchar *) GST_BUFFER_DATA (buffer) + offset; + + if (len >= (3 + 1) && IS_BOM_UTF8 (data) && + g_utf8_validate (data + 3, len - 3, NULL)) { + ret = gst_buffer_create_sub (buffer, offset + 3, len - 3); + } else if (len >= 2 && IS_BOM_UTF16_BE (data)) { + input_enc = "UTF-16BE"; + data += 2; + len -= 2; + } else if (len >= 2 && IS_BOM_UTF16_LE (data)) { + input_enc = "UTF-16LE"; + data += 2; + len -= 2; + } else if (len >= 4 && IS_BOM_UTF32_BE (data)) { + input_enc = "UTF-32BE"; + data += 4; + len -= 4; + } else if (len >= 4 && IS_BOM_UTF32_LE (data)) { + input_enc = "UTF-32LE"; + data += 4; + len -= 4; + } else if (g_utf8_validate (data, len, NULL)) { + /* not specified, check if it's UTF-8 */ + ret = gst_buffer_create_sub (buffer, offset, len); + } else { + /* we could fall back to gst_tag_freeform_to_utf8() here */ + GST_WARNING_OBJECT (sub, "unspecified encoding, and not UTF-8"); + return NULL; + } + + g_return_val_if_fail (ret != NULL || input_enc != NULL, NULL); + + if (input_enc) { + GError *err = NULL; + gchar *utf8; + + GST_DEBUG_OBJECT (sub, "converting subtitles from %s to UTF-8", input_enc); + utf8 = g_convert (data, len, "UTF-8", input_enc, NULL, NULL, &err); + + if (err != NULL) { + GST_WARNING_OBJECT (sub, "conversion to UTF-8 failed : %s", err->message); + g_error_free (err); + return NULL; + } + + ret = gst_buffer_new (); + GST_BUFFER_DATA (ret) = (guint8 *) utf8; + GST_BUFFER_MALLOCDATA (ret) = (guint8 *) utf8; + GST_BUFFER_SIZE (ret) = strlen (utf8); + GST_BUFFER_OFFSET (ret) = 0; + } + + GST_BUFFER_CAPS (ret) = gst_caps_new_simple ("application/x-subtitle", NULL); + return ret; +} + +/** + * gst_avi_subtitle_title_tag: + * @sub: subtitle element + * @title: the title of this subtitle stream + * + * Send an event to the srcpad of the @sub element with the title + * of the subtitle stream as a GST_TAG_TITLE + */ +static void +gst_avi_subtitle_title_tag (GstAviSubtitle * sub, gchar * title) +{ + GstTagList *temp_list = gst_tag_list_new (); + + gst_tag_list_add (temp_list, GST_TAG_MERGE_APPEND, GST_TAG_TITLE, title, + NULL); + gst_pad_push_event (sub->src, gst_event_new_tag (temp_list)); +} + +static GstFlowReturn +gst_avi_subtitle_parse_gab2_chunk (GstAviSubtitle * sub, GstBuffer * buf) +{ + const guint8 *data; + gchar *name_utf8; + guint name_length; + guint file_length; + guint size; + + data = GST_BUFFER_DATA (buf); + size = GST_BUFFER_SIZE (buf); + + /* check the magic word "GAB2\0", and the next word must be 2 */ + if (size < 12 || memcmp (data, "GAB2\0\2\0", 5 + 2) != 0) + goto wrong_magic_word; + + /* read 'name' of subtitle */ + name_length = GST_READ_UINT32_LE (data + 5 + 2); + GST_LOG_OBJECT (sub, "length of name: %u", name_length); + if (size <= 17 + name_length) + goto wrong_name_length; + + name_utf8 = g_convert ((gchar *) data + 11, name_length, "UTF-8", "UTF-16LE", + NULL, NULL, NULL); + + if (name_utf8) { + GST_LOG_OBJECT (sub, "subtitle name: %s", name_utf8); + gst_avi_subtitle_title_tag (sub, name_utf8); + g_free (name_utf8); + } + + /* next word must be 4 */ + if (GST_READ_UINT16_LE (data + 11 + name_length) != 0x4) + goto wrong_fixed_word_2; + + file_length = GST_READ_UINT32_LE (data + 13 + name_length); + GST_LOG_OBJECT (sub, "length srt/ssa file: %u", file_length); + + if (size < (17 + name_length + file_length)) + goto wrong_total_length; + + /* store this, so we can send it again after a seek; note that we shouldn't + * assume all the remaining data in the chunk is subtitle data, there may + * be padding at the end for some reason, so only parse file_length bytes */ + sub->subfile = + gst_avi_subtitle_extract_file (sub, buf, 17 + name_length, file_length); + + if (sub->subfile == NULL) + goto extract_failed; + + return GST_FLOW_OK; + + /* ERRORS */ +wrong_magic_word: + { + GST_ELEMENT_ERROR (sub, STREAM, DECODE, (NULL), ("Wrong magic word")); + return GST_FLOW_ERROR; + } +wrong_name_length: + { + GST_ELEMENT_ERROR (sub, STREAM, DECODE, (NULL), + ("name doesn't fit in buffer (%d < %d)", size, 17 + name_length)); + return GST_FLOW_ERROR; + } +wrong_fixed_word_2: + { + GST_ELEMENT_ERROR (sub, STREAM, DECODE, (NULL), + ("wrong fixed word: expected %u, got %u", 4, + GST_READ_UINT16_LE (data + 11 + name_length))); + return GST_FLOW_ERROR; + } +wrong_total_length: + { + GST_ELEMENT_ERROR (sub, STREAM, DECODE, (NULL), + ("buffer size is wrong: need %d bytes, have %d bytes", + 17 + name_length + file_length, size)); + return GST_FLOW_ERROR; + } +extract_failed: + { + GST_ELEMENT_ERROR (sub, STREAM, DECODE, (NULL), + ("could not extract subtitles")); + return GST_FLOW_ERROR; + } +} + +static GstFlowReturn +gst_avi_subtitle_chain (GstPad * pad, GstBuffer * buffer) +{ + GstAviSubtitle *sub = GST_AVI_SUBTITLE (GST_PAD_PARENT (pad)); + GstFlowReturn ret; + + if (sub->subfile != NULL) { + GST_WARNING_OBJECT (sub, "Got more buffers than expected, dropping"); + ret = GST_FLOW_UNEXPECTED; + goto done; + } + + /* we expect exactly one buffer with the whole srt/ssa file in it */ + ret = gst_avi_subtitle_parse_gab2_chunk (sub, buffer); + if (ret != GST_FLOW_OK) + goto done; + + /* now push the subtitle data downstream */ + ret = gst_pad_push (sub->src, gst_buffer_ref (sub->subfile)); + +done: + + gst_buffer_unref (buffer); + return ret; +} + +static gboolean +gst_avi_subtitle_send_event (GstElement * element, GstEvent * event) +{ + GstAviSubtitle *avisubtitle = GST_AVI_SUBTITLE (element); + gboolean ret = FALSE; + + if (GST_EVENT_TYPE (event) == GST_EVENT_SEEK) { + if (avisubtitle->subfile) { + if (gst_pad_push (avisubtitle->src, + gst_buffer_ref (avisubtitle->subfile)) == GST_FLOW_OK) + ret = TRUE; + } + } + gst_event_unref (event); + return ret; +} + +static void +gst_avi_subtitle_base_init (gpointer klass) +{ + GstElementClass *element_class = GST_ELEMENT_CLASS (klass); + + GST_DEBUG_CATEGORY_INIT (avisubtitle_debug, "avisubtitle", 0, + "parse avi subtitle stream"); + + gst_element_class_add_static_pad_template (element_class, + &sink_template); + gst_element_class_add_static_pad_template (element_class, &src_template); + + gst_element_class_set_details_simple (element_class, + "Avi subtitle parser", "Codec/Parser/Subtitle", + "Parse avi subtitle stream", "Thijs Vermeir <thijsvermeir@gmail.com>"); +} + +static void +gst_avi_subtitle_class_init (GstAviSubtitleClass * klass) +{ + GstElementClass *gstelement_class = (GstElementClass *) klass; + + gstelement_class->change_state = + GST_DEBUG_FUNCPTR (gst_avi_subtitle_change_state); + gstelement_class->send_event = + GST_DEBUG_FUNCPTR (gst_avi_subtitle_send_event); +} + +static void +gst_avi_subtitle_init (GstAviSubtitle * self, GstAviSubtitleClass * klass) +{ + GstCaps *caps; + + self->src = gst_pad_new_from_static_template (&src_template, "src"); + gst_element_add_pad (GST_ELEMENT (self), self->src); + + self->sink = gst_pad_new_from_static_template (&sink_template, "sink"); + gst_pad_set_chain_function (self->sink, + GST_DEBUG_FUNCPTR (gst_avi_subtitle_chain)); + + caps = gst_static_pad_template_get_caps (&src_template); + gst_pad_set_caps (self->src, caps); + gst_caps_unref (caps); + + gst_pad_use_fixed_caps (self->src); + gst_element_add_pad (GST_ELEMENT (self), self->sink); + + self->subfile = NULL; +} + +static GstStateChangeReturn +gst_avi_subtitle_change_state (GstElement * element, GstStateChange transition) +{ + GstStateChangeReturn ret; + GstAviSubtitle *sub = GST_AVI_SUBTITLE (element); + + switch (transition) { + case GST_STATE_CHANGE_NULL_TO_READY: + case GST_STATE_CHANGE_READY_TO_PAUSED: + default: + break; + } + + ret = GST_ELEMENT_CLASS (parent_class)->change_state (element, transition); + if (ret == GST_STATE_CHANGE_FAILURE) + return ret; + + switch (transition) { + case GST_STATE_CHANGE_PAUSED_TO_READY: + if (sub->subfile) { + gst_buffer_unref (sub->subfile); + sub->subfile = NULL; + } + break; + default: + break; + } + + return ret; +} |