new id3v2 muxer based on TagLib

Original commit message from CVS:
2006-03-09  Christophe Fergeau  <teuf@gnome.org>

reviewed by: Tim-Philipp Müller  <tim at centricular dot net>

* configure.ac:
* ext/Makefile.am:
* ext/taglib/Makefile.am:
* ext/taglib/gsttaglib.cc:
* ext/taglib/gsttaglib.h: new id3v2 muxer based on TagLib

ext/taglib/Makefile.am

+plugin_LTLIBRARIES = libgsttaglib.la
+
+libgsttaglib_la_SOURCES = gsttaglib.cc
+libgsttaglib_la_CXXFLAGS = $(GST_CFLAGS) $(TAGLIB_CFLAGS)
+libgsttaglib_la_LIBADD = $(GST_LIBS) $(TAGLIB_LIBS)
+libgsttaglib_la_LDFLAGS = $(GST_PLUGIN_LDFLAGS)
+
+noinst_HEADERS = gsttaglib.h 
+
+#EXTRA_DIST = README

ext/taglib/gsttaglibmux.c

+/*
+ * (c) 2006 Christophe Fergeau  <teuf@gnome.org>
+ *
+ * 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.
+ */
+
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <string.h>
+#include <textidentificationframe.h>
+#include <id3v2tag.h>
+#include <gst/gsttagsetter.h>
+#include "gsttaglib.h"
+
+using namespace TagLib;
+
+GST_DEBUG_CATEGORY_STATIC (gst_tag_lib_mux_debug);
+#define GST_CAT_DEFAULT gst_tag_lib_mux_debug
+
+static void
+gst_tag_lib_mux_iface_init (GType taglib_type)
+{
+  static const GInterfaceInfo tag_setter_info = {
+    NULL,
+    NULL,
+    NULL
+  };
+
+  g_type_add_interface_static (taglib_type, GST_TYPE_TAG_SETTER,
+      &tag_setter_info);
+}
+
+GST_BOILERPLATE_FULL (GstTagLibMux, gst_tag_lib_mux,
+    GstElement, GST_TYPE_ELEMENT, gst_tag_lib_mux_iface_init);
+
+
+static GstStateChangeReturn
+gst_tag_lib_mux_change_state (GstElement * element, GstStateChange transition);
+static GstFlowReturn gst_tag_lib_mux_chain (GstPad * pad, GstBuffer * buffer);
+static gboolean gst_tag_lib_mux_sink_event (GstPad * pad, GstEvent * event);
+
+
+static void
+gst_tag_lib_mux_finalize (GObject * obj)
+{
+  GstTagLibMux *taglib = GST_TAGLIB_MUX (obj);
+
+  if (taglib->tags) {
+    gst_tag_list_free (taglib->tags);
+    taglib->tags = NULL;
+  }
+  G_OBJECT_CLASS (parent_class)->finalize (obj);
+}
+
+
+static GstStaticPadTemplate gst_tag_lib_mux_sink_template =
+GST_STATIC_PAD_TEMPLATE ("sink",
+    GST_PAD_SINK,
+    GST_PAD_ALWAYS,
+    GST_STATIC_CAPS ("audio/mpeg"));
+
+
+static GstStaticPadTemplate gst_tag_lib_mux_src_template =
+GST_STATIC_PAD_TEMPLATE ("src",
+    GST_PAD_SRC,
+    GST_PAD_ALWAYS,
+    GST_STATIC_CAPS ("application/x-id3"));
+
+
+static void
+gst_tag_lib_mux_base_init (gpointer g_class)
+{
+  GstElementClass *element_class = GST_ELEMENT_CLASS (g_class);
+
+  static GstElementDetails gst_tag_lib_mux_details = {
+    "TagLib ID3 Muxer",
+    "Formatter/Metadata",
+    "Adds an ID3v2 header to the beginning of MP3 files",
+    "Christophe Fergeau <teuf@gnome.org>"
+  };
+
+
+  gst_element_class_add_pad_template (element_class,
+      gst_static_pad_template_get (&gst_tag_lib_mux_src_template));
+  gst_element_class_add_pad_template (element_class,
+      gst_static_pad_template_get (&gst_tag_lib_mux_sink_template));
+  gst_element_class_set_details (element_class, &gst_tag_lib_mux_details);
+}
+
+static void
+gst_tag_lib_mux_class_init (GstTagLibMuxClass * klass)
+{
+  GObjectClass *gobject_class;
+  GstElementClass *gstelement_class;
+
+  gobject_class = (GObjectClass *) klass;
+  gstelement_class = (GstElementClass *) klass;
+
+  gobject_class->finalize = GST_DEBUG_FUNCPTR (gst_tag_lib_mux_finalize);
+  gstelement_class->change_state =
+      GST_DEBUG_FUNCPTR (gst_tag_lib_mux_change_state);
+}
+
+static void
+gst_tag_lib_mux_init (GstTagLibMux * taglib,
+    GstTagLibMuxClass * taglibmux_class)
+{
+  GstElementClass *klass = GST_ELEMENT_CLASS (taglibmux_class);
+
+  /* pad through which data comes in to the element */
+  taglib->sinkpad =
+      gst_pad_new_from_template (gst_element_class_get_pad_template (klass,
+          "sink"), "sink");
+  gst_pad_set_setcaps_function (taglib->sinkpad,
+      GST_DEBUG_FUNCPTR (gst_pad_proxy_setcaps));
+  gst_pad_set_chain_function (taglib->sinkpad,
+      GST_DEBUG_FUNCPTR (gst_tag_lib_mux_chain));
+  gst_pad_set_event_function (taglib->sinkpad,
+      GST_DEBUG_FUNCPTR (gst_tag_lib_mux_sink_event));
+  gst_element_add_pad (GST_ELEMENT (taglib), taglib->sinkpad);
+
+  /* pad through which data goes out of the element */
+  taglib->srcpad =
+      gst_pad_new_from_template (gst_element_class_get_pad_template (klass,
+          "src"), "src");
+  gst_element_add_pad (GST_ELEMENT (taglib), taglib->srcpad);
+
+  taglib->render_tag = TRUE;
+}
+
+static void
+add_one_tag (const GstTagList * list, const gchar * tag, gpointer user_data)
+{
+  ID3v2::Tag * id3v2tag = (ID3v2::Tag *) user_data;
+  gboolean result;
+
+  /* FIXME: if there are several values set for the same tag, this won't
+   * work, only the first value will be taken into account
+   */
+  if (strcmp (tag, GST_TAG_TITLE) == 0) {
+    char *title;
+
+    result = gst_tag_list_get_string_index (list, tag, 0, &title);
+    if (result != FALSE) {
+      GST_DEBUG ("Setting title to %s", title);
+      id3v2tag->setTitle (String::String (title, String::UTF8));
+    }
+    g_free (title);
+  } else if (strcmp (tag, GST_TAG_ALBUM) == 0) {
+    char *album;
+
+    result = gst_tag_list_get_string_index (list, tag, 0, &album);
+    if (result != FALSE) {
+      GST_DEBUG ("Setting album to %s", album);
+      id3v2tag->setAlbum (String::String (album, String::UTF8));
+    }
+    g_free (album);
+  } else if (strcmp (tag, GST_TAG_ARTIST) == 0) {
+    char *artist;
+
+    result = gst_tag_list_get_string_index (list, tag, 0, &artist);
+    if (result != FALSE) {
+      GST_DEBUG ("Setting artist to %s", artist);
+      id3v2tag->setArtist (String::String (artist, String::UTF8));
+    }
+    g_free (artist);
+  } else if (strcmp (tag, GST_TAG_GENRE) == 0) {
+    char *genre;
+
+    result = gst_tag_list_get_string_index (list, tag, 0, &genre);
+    if (result != FALSE) {
+      GST_DEBUG ("Setting genre to %s", genre);
+      id3v2tag->setGenre (String::String (genre, String::UTF8));
+    }
+    g_free (genre);
+  } else if (strcmp (tag, GST_TAG_COMMENT) == 0) {
+    char *comment;
+
+    result = gst_tag_list_get_string_index (list, tag, 0, &comment);
+    if (result != FALSE) {
+      GST_DEBUG ("Setting comment to %s", comment);
+      id3v2tag->setComment (String::String (comment, String::UTF8));
+    }
+    g_free (comment);
+  } else if (strcmp (tag, GST_TAG_DATE) == 0) {
+    GDate *date;
+
+    result = gst_tag_list_get_date_index (list, tag, 0, &date);
+    if (result != FALSE) {
+      GDateYear year;
+
+      year = g_date_get_year (date);
+      GST_DEBUG ("Setting track year to %d", year);
+      id3v2tag->setYear (year);
+      g_date_free (date);
+    }
+  } else if (strcmp (tag, GST_TAG_TRACK_NUMBER) == 0) {
+    guint track_number;
+
+    result = gst_tag_list_get_uint_index (list, tag, 0, &track_number);
+    if (result != FALSE) {
+      guint total_tracks;
+
+      result = gst_tag_list_get_uint_index (list, GST_TAG_TRACK_COUNT,
+          0, &total_tracks);
+      if (result) {
+        gchar *tag_str;
+
+        ID3v2::TextIdentificationFrame * frame;
+
+        frame = new ID3v2::TextIdentificationFrame ("TRCK", String::UTF8);
+        tag_str = g_strdup_printf ("%d/%d", track_number, total_tracks);
+        GST_DEBUG ("Setting track number to %s", tag_str);
+        id3v2tag->addFrame (frame);
+        frame->setText (tag_str);
+        g_free (tag_str);
+      } else {
+        GST_DEBUG ("Setting track number to %d", track_number);
+        id3v2tag->setTrack (track_number);
+      }
+    }
+  } else if (strcmp (tag, GST_TAG_ALBUM_VOLUME_NUMBER) == 0) {
+    guint volume_number;
+
+    result = gst_tag_list_get_uint_index (list, tag, 0, &volume_number);
+
+    if (result != FALSE) {
+      guint volume_count;
+      gchar *tag_str;
+
+      ID3v2::TextIdentificationFrame * frame;
+
+      frame = new ID3v2::TextIdentificationFrame ("TRCK", String::UTF8);
+      result = gst_tag_list_get_uint_index (list, GST_TAG_ALBUM_VOLUME_COUNT,
+          0, &volume_count);
+      if (result) {
+        tag_str = g_strdup_printf ("%d/%d", volume_number, volume_count);
+      } else {
+        tag_str = g_strdup_printf ("%d", volume_number);
+      }
+
+      id3v2tag->addFrame (frame);
+      frame->setText (tag_str);
+      g_free (tag_str);
+      GST_DEBUG ("Setting track number to %s", tag_str);
+    }
+  } else {
+    GST_WARNING ("Unsupported tag: %s", tag);
+  }
+}
+
+
+static GstBuffer *
+gst_tag_lib_mux_render_tag (GstTagLibMux * taglib)
+{
+  ID3v2::Tag id3v2tag;
+  ByteVector rendered_tag;
+  GstBuffer *buffer;
+  GstTagSetter *tagsetter = GST_TAG_SETTER (taglib);
+  GstTagList *taglist;
+  GstEvent *event;
+
+  if (taglib->tags != NULL) {
+    taglist = gst_tag_list_copy (taglib->tags);
+  } else {
+    taglist = gst_tag_list_new ();
+  }
+
+  if (gst_tag_setter_get_tag_list (tagsetter)) {
+    gst_tag_list_insert (taglist,
+        gst_tag_setter_get_tag_list (tagsetter),
+        gst_tag_setter_get_tag_merge_mode (tagsetter));
+  }
+
+
+  /* Render the tag */
+  gst_tag_list_foreach (taglist, add_one_tag, &id3v2tag);
+  rendered_tag = id3v2tag.render ();
+  taglib->tag_size = rendered_tag.size ();
+  buffer = gst_buffer_new_and_alloc (rendered_tag.size ());
+  memcpy (GST_BUFFER_DATA (buffer), rendered_tag.data (), rendered_tag.size ());
+  gst_buffer_set_caps (buffer, GST_PAD_CAPS (taglib->srcpad));
+  /*  gst_util_dump_mem (GST_BUFFER_DATA (buffer), rendered_tag.size()); */
+
+  /* Send an event about the new tags to downstream elements */
+  /* gst_event_new_tag takes ownership of the list, so no need to unref it */
+  event = gst_event_new_tag (taglist);
+  gst_pad_push_event (taglib->srcpad, event);
+
+  return buffer;
+}
+
+
+static GstFlowReturn
+gst_tag_lib_mux_chain (GstPad * pad, GstBuffer * buffer)
+{
+  GstTagLibMux *taglib = GST_TAGLIB_MUX (GST_OBJECT_PARENT (pad));
+
+  if (taglib->render_tag) {
+    GstFlowReturn ret;
+
+    GST_INFO ("Adding tags to stream");
+    ret = gst_pad_push (taglib->srcpad, gst_tag_lib_mux_render_tag (taglib));
+    if (ret != GST_FLOW_OK) {
+      gst_buffer_unref (buffer);
+      return ret;
+    }
+    taglib->render_tag = FALSE;
+  }
+
+  gst_buffer_set_caps (buffer, GST_PAD_CAPS (taglib->srcpad));
+  return gst_pad_push (taglib->srcpad, buffer);
+}
+
+static gboolean
+gst_tag_lib_mux_sink_event (GstPad * pad, GstEvent * event)
+{
+  GstTagLibMux *taglib;
+  gboolean result;
+
+  taglib = GST_TAGLIB_MUX (gst_pad_get_parent (pad));
+  result = FALSE;
+
+  switch (GST_EVENT_TYPE (event)) {
+    case GST_EVENT_TAG:
+    {
+      GstTagList *tags;
+
+      GST_INFO ("Got tag event");
+
+      gst_event_parse_tag (event, &tags);
+      if (taglib->tags != NULL) {
+        /* FIXME: which policy is the best here? PREPEND or something else? */
+        gst_tag_list_insert (taglib->tags, tags, GST_TAG_MERGE_PREPEND);
+      } else {
+        taglib->tags = gst_tag_list_copy (tags);
+      }
+      /* We'll push a new tag event in render_tag */
+      gst_event_unref (event);
+      result = TRUE;
+      break;
+    }
+    case GST_EVENT_NEWSEGMENT:
+      if (taglib->tag_size == 0) {
+        result = gst_pad_push_event (taglib->srcpad, event);
+      } else {
+        gboolean update;
+        gdouble rate;
+        GstFormat format;
+        gint64 value, end_value, base;
+
+        gst_event_parse_new_segment (event, &update, &rate, &format,
+            &value, &end_value, &base);
+        gst_event_unref (event);
+        if (format == GST_FORMAT_BYTES && gst_pad_is_linked (taglib->srcpad)) {
+          GstEvent *new_event;
+
+          GST_INFO ("Adjusting NEW_SEGMENT event by %d", taglib->tag_size);
+          value += taglib->tag_size;
+          if (end_value != -1) {
+            end_value += taglib->tag_size;
+          }
+
+          new_event = gst_event_new_new_segment (update, rate, format,
+              value, end_value, base);
+          result = gst_pad_push_event (taglib->srcpad, new_event);
+        } else {
+          result = FALSE;
+        }
+      }
+      break;
+
+    default:
+      result = gst_pad_event_default (pad, event);
+      break;
+  }
+  gst_object_unref (GST_OBJECT (taglib));
+
+  return result;
+}
+
+
+static GstStateChangeReturn
+gst_tag_lib_mux_change_state (GstElement * element, GstStateChange transition)
+{
+  GstTagLibMux *taglib;
+  GstStateChangeReturn result;
+
+  taglib = GST_TAGLIB_MUX (element);
+
+  result = GST_ELEMENT_CLASS (parent_class)->change_state (element, transition);
+  if (result != GST_STATE_CHANGE_SUCCESS) {
+    return result;
+  }
+
+  switch (transition) {
+    case GST_STATE_CHANGE_PAUSED_TO_READY:
+      if (taglib->tags) {
+        gst_tag_list_free (taglib->tags);
+        taglib->tags = NULL;
+      }
+      taglib->tag_size = 0;
+      taglib->render_tag = TRUE;
+      break;
+    default:
+      break;
+  }
+
+  return result;
+}
+
+
+static gboolean
+plugin_init (GstPlugin * plugin)
+{
+  if (!gst_element_register (plugin, "tagid3v2mux", GST_RANK_NONE,
+          GST_TYPE_TAGLIB_MUX))
+    return FALSE;
+
+  GST_DEBUG_CATEGORY_INIT (gst_tag_lib_mux_debug, "taglibmux", 0,
+      "ID3 Tag Muxer");
+
+  return TRUE;
+}
+
+GST_PLUGIN_DEFINE (GST_VERSION_MAJOR,
+    GST_VERSION_MINOR,
+    "taglibmux",
+    "Tag-writing plug-in based on taglib",
+    plugin_init, VERSION, "LGPL", GST_PACKAGE, GST_ORIGIN)

ext/taglib/gsttaglibmux.h

+/*
+ * (c) 2006 Christophe Fergeau  <teuf@gnome.org>
+ *
+ * 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.
+ */
+
+#ifndef GST_TAG_LIB_H
+#define GST_TAG_LIB_H
+
+#include <gst/gst.h>
+
+G_BEGIN_DECLS
+
+typedef struct _GstTagLibMuxPriv GstTagLibMuxPriv;
+
+/* Definition of structure storing data for this element. */
+typedef struct _GstTagLibMux {
+  GstElement element;
+
+  GstPad *sinkpad, *srcpad;
+  GstTagList *tags;
+  gsize tag_size;
+  gboolean render_tag;
+
+} GstTagLibMux;
+
+/* Standard definition defining a class for this element. */
+typedef struct _GstTagLibMuxClass {
+  GstElementClass parent_class;
+} GstTagLibMuxClass;
+
+/* Standard macros for defining types for this element.  */
+#define GST_TYPE_TAGLIB_MUX \
+  (gst_tag_lib_mux_get_type())
+#define GST_TAGLIB_MUX(obj) \
+  (G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_TAGLIB_MUX,GstTagLibMux))
+#define GST_TAGLIB_MUX_CLASS(klass) \
+  (G_TYPE_CHECK_CLASS_CAST((klass),GST_TYPE_TAGLIB_MUX,GstTagLibMuxClass))
+#define GST_IS_TAGLIB_MUX(obj) \
+  (G_TYPE_CHECK_INSTANCE_TYPE((obj),GST_TYPE_TAGLIB_MUX))
+#define GST_IS_TAGLIB_MUX_CLASS(obj) \
+  (G_TYPE_CHECK_CLASS_TYPE((klass),GST_TYPE_TAGLIB_MUX))
+
+/* Standard function returning type information. */
+GType gst_my_filter_get_type (void);
+
+G_END_DECLS
+
+#endif