[sound-juicer] Fix MP3 encoding

[Phillip Wood <pwood src gnome org>]

commit 7eefb93d161b1f9f72c6c29884bb76b1b1292eb8
Author: Phillip Wood <phillip wood dunelm org uk>
Date:   Tue Oct 15 11:03:11 2013 +0100

    Fix MP3 encoding
    
    Gstreamer's encodebin creates variable bitrate MP3 files without an
    Xing header (bug 649841) which means their length and bitrate are
    misreported. Fix this by making MP3 a special case with our own
    pipeline and element checking rather than using encodebin.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=675275

 libjuicer/sj-extractor.c |   36 ++++++++++++++++++++++++++++++------
 1 files changed, 30 insertions(+), 6 deletions(-)
---
diff --git a/libjuicer/sj-extractor.c b/libjuicer/sj-extractor.c
index 99874a6..4b70439 100644
--- a/libjuicer/sj-extractor.c
+++ b/libjuicer/sj-extractor.c
@@ -271,17 +271,25 @@ build_encoder (SjExtractor *extractor)
 {
   SjExtractorPrivate *priv;
   GstElement *encodebin;
+  const char *profile_name;
+  static const char * mp3_pipeline = "lamemp3enc ! xingmux ! id3v2mux";
 
   g_return_val_if_fail (SJ_IS_EXTRACTOR (extractor), NULL);
   priv = (SjExtractorPrivate*)extractor->priv;
   g_return_val_if_fail (priv->profile != NULL, NULL);
 
-  encodebin = gst_element_factory_make ("encodebin", NULL);
-  if (encodebin == NULL)
-    return NULL;
-  g_object_set (encodebin, "profile", priv->profile, NULL);
-  /* Nice big buffers... */
-  g_object_set (encodebin, "queue-time-max", 120 * GST_SECOND, NULL);
+  /* encodebin does not use xingmux so do mp3 pipeline ourselves */
+  profile_name = gst_encoding_profile_get_name (priv->profile);
+  if (strcmp (profile_name, "mp3") == 0) {
+    encodebin = gst_parse_bin_from_description (mp3_pipeline, TRUE, NULL);
+  } else {
+    encodebin = gst_element_factory_make ("encodebin", NULL);
+    if (encodebin == NULL)
+      return NULL;
+    g_object_set (encodebin, "profile", priv->profile, NULL);
+    /* Nice big buffers... */
+    g_object_set (encodebin, "queue-time-max", 120 * GST_SECOND, NULL);
+  }
 
   return encodebin;
 }
@@ -697,5 +705,21 @@ gboolean
 sj_extractor_supports_profile (GstEncodingProfile *profile)
 {
   /* TODO: take a GError to return a message if the profile isn't supported */
+  const gchar *profile_name = gst_encoding_profile_get_name (profile);
+  if (strcmp (profile_name, "mp3") == 0) {
+    GstElementFactory *factory = gst_element_factory_find ("lamemp3enc");
+    if (factory == NULL)
+      return FALSE;
+    g_object_unref (factory);
+    factory = gst_element_factory_find ("xingmux");
+    if (factory == NULL)
+      return FALSE;
+    g_object_unref (factory);
+    factory = gst_element_factory_find ("id3v2mux");
+    if (factory == NULL)
+      return FALSE;
+    g_object_unref (factory);
+    return TRUE;
+  }
   return !rb_gst_check_missing_plugins(profile, NULL, NULL);
 }