examples: encoding example

Along with gstcapslist

configure.ac

@@ -995,6 +995,7 @@ tests/check/Makefile
 tests/examples/Makefile
 tests/examples/app/Makefile
 tests/examples/dynamic/Makefile
+tests/examples/encoding/Makefile
 tests/examples/gio/Makefile
 tests/examples/overlay/Makefile
 tests/examples/seek/Makefile

tests/examples/Makefile.am

@@ -8,8 +8,8 @@ if USE_GIO
 GIO_SUBDIRS = gio
 endif
 
-SUBDIRS = app  dynamic $(FT2_SUBDIRS) $(GIO_SUBDIRS) overlay playrec volume v4l
+SUBDIRS = app  dynamic $(FT2_SUBDIRS) $(GIO_SUBDIRS) overlay playrec volume v4l encoding
 
-DIST_SUBDIRS = app dynamic gio overlay seek snapshot playrec volume v4l
+DIST_SUBDIRS = app dynamic gio overlay seek snapshot playrec volume v4l encoding
 
 include $(top_srcdir)/common/parallel-subdirs.mak

tests/examples/encoding/.gitignore

@@ -0,0 +1 @@
+encoding

tests/examples/encoding/Makefile.am

@@ -0,0 +1,11 @@
+examples = encoding
+
+encoding_SOURCES = gstcapslist.c encoding.c
+EXTRA_DIST = gstcapslist.h
+
+noinst_PROGRAMS = $(examples)
+
+LDADD = $(top_builddir)/gst-libs/gst/pbutils/libgstpbutils-@GST_MAJORMINOR@.la\
+	-lgstpbutils-@GST_MAJORMINOR@
+	$(GST_LIBS)
+AM_CFLAGS = -I$(top_builddir)/gst-libs $(GST_PLUGINS_BASE_CFLAGS) $(GST_BASE_CFLAGS) $(GST_CFLAGS)

tests/examples/encoding/encoding.c

@@ -0,0 +1,512 @@
+/* Example application for using GstProfile and encodebin
+ * Copyright (C) 2009 Edward Hervey <edward.hervey@collabora.co.uk>
+ *
+ * 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 <stdlib.h>
+#include <glib.h>
+#include <glib/gprintf.h>
+#include <gst/gst.h>
+#include <gst/pbutils/pbutils.h>
+#include <gst/pbutils/encoding-profile.h>
+#include "gstcapslist.h"
+
+static gboolean silent = FALSE;
+
+static void
+list_codecs (void)
+{
+  GstCaps *l;
+  GstCaps *caps;
+  guint i, len;
+
+  caps = gst_caps_new_empty ();
+
+  g_print ("Available container formats:\n");
+  l = gst_caps_list_container_formats (GST_RANK_NONE);
+  len = gst_caps_get_size (l);
+  for (i = 0; i < len; i++) {
+    GstStructure *st = gst_caps_steal_structure (l, 0);
+    gchar *tmpstr, *desc;
+
+    gst_caps_append_structure (caps, st);
+
+    tmpstr = gst_caps_to_string (caps);
+    desc = gst_pb_utils_get_codec_description (caps);
+    g_print ("  %s - %s\n", desc, tmpstr);
+    g_free (tmpstr);
+    if (desc)
+      g_free (desc);
+    gst_caps_remove_structure (caps, 0);
+  }
+  g_print ("\n");
+  gst_caps_unref (l);
+
+  g_print ("Available video codecs:\n");
+  l = gst_caps_list_video_encoding_formats (GST_RANK_NONE);
+  len = gst_caps_get_size (l);
+  for (i = 0; i < len; i++) {
+    GstStructure *st = gst_caps_steal_structure (l, 0);
+    gchar *tmpstr, *desc;
+
+    gst_caps_append_structure (caps, st);
+
+    tmpstr = gst_caps_to_string (caps);
+    desc = gst_pb_utils_get_codec_description (caps);
+    g_print ("  %s - %s\n", desc, tmpstr);
+    g_free (tmpstr);
+    if (desc)
+      g_free (desc);
+    gst_caps_remove_structure (caps, 0);
+  }
+  g_print ("\n");
+  gst_caps_unref (l);
+
+  g_print ("Available audio codecs:\n");
+  l = gst_caps_list_audio_encoding_formats (GST_RANK_NONE);
+  len = gst_caps_get_size (l);
+  for (i = 0; i < len; i++) {
+    GstStructure *st = gst_caps_steal_structure (l, 0);
+    gchar *tmpstr, *desc;
+
+    gst_caps_append_structure (caps, st);
+
+    tmpstr = gst_caps_to_string (caps);
+    desc = gst_pb_utils_get_codec_description (caps);
+    g_print ("  %s - %s\n", desc, tmpstr);
+    g_free (tmpstr);
+    if (desc)
+      g_free (desc);
+    gst_caps_remove_structure (caps, 0);
+  }
+  g_print ("\n");
+  gst_caps_unref (l);
+
+  gst_caps_unref (caps);
+}
+
+static gchar *
+generate_filename (const GstCaps * container, const GstCaps * vcodec,
+    const GstCaps * acodec)
+{
+  gchar *a, *b, *c;
+  gchar *res = NULL;
+  guint i;
+
+  a = gst_pb_utils_get_codec_description (container);
+  b = gst_pb_utils_get_codec_description (vcodec);
+  c = gst_pb_utils_get_codec_description (acodec);
+
+  if (!a)
+    a = g_strdup_printf ("%.10s",
+        g_uri_escape_string (gst_caps_to_string (container), NULL, FALSE));
+  if (!b)
+    b = g_strdup_printf ("%.10s",
+        g_uri_escape_string (gst_caps_to_string (vcodec), NULL, FALSE));
+  if (!c)
+    c = g_strdup_printf ("%.10s",
+        g_uri_escape_string (gst_caps_to_string (acodec), NULL, FALSE));
+
+  for (i = 0; i < 256 && res == NULL; i++) {
+    res = g_strdup_printf ("%s-%s-%s-%d.file", a, b, c, i);
+    if (g_file_test (res, G_FILE_TEST_EXISTS)) {
+      g_free (res);
+      res = NULL;
+    }
+  }
+  /* Make sure file doesn't already exist */
+
+  g_free (a);
+  g_free (b);
+  g_free (c);
+
+  return res;
+}
+
+static GstEncodingProfile *
+create_profile (GstCaps * cf, GstCaps * vf, GstCaps * af)
+{
+  GstEncodingContainerProfile *cprof = NULL;
+
+  cprof =
+      gst_encoding_container_profile_new ((gchar *) "test-application-profile",
+      NULL, cf, NULL);
+
+  if (vf)
+    gst_encoding_container_profile_add_profile (cprof,
+        (GstEncodingProfile *) gst_encoding_video_profile_new (vf,
+            NULL, NULL, 0));
+  if (af)
+    gst_encoding_container_profile_add_profile (cprof, (GstEncodingProfile *)
+        gst_encoding_audio_profile_new (af, NULL, NULL, 0));
+
+  /* Let's print out some info */
+  if (!silent) {
+    gchar *desc = gst_pb_utils_get_codec_description (cf);
+    gchar *cd = gst_caps_to_string (cf);
+    g_print ("Encoding parameters\n");
+    g_print ("  Container format : %s (%s)\n", desc, cd);
+    g_free (desc);
+    g_free (cd);
+    if (vf) {
+      desc = gst_pb_utils_get_codec_description (vf);
+      cd = gst_caps_to_string (vf);
+      g_print ("  Video format : %s (%s)\n", desc, cd);
+      g_free (desc);
+      g_free (cd);
+    }
+    if (af) {
+      desc = gst_pb_utils_get_codec_description (af);
+      cd = gst_caps_to_string (af);
+      g_print ("  Audio format : %s (%s)\n", desc, cd);
+      g_free (desc);
+      g_free (cd);
+    }
+  }
+
+  return (GstEncodingProfile *) cprof;
+}
+
+static GstEncodingProfile *
+create_profile_from_string (gchar * format, gchar * vformat, gchar * aformat)
+{
+  GstEncodingProfile *prof = NULL;
+  GstCaps *cf = NULL, *vf = NULL, *af = NULL;
+
+  if (format)
+    cf = gst_caps_from_string (format);
+  if (vformat)
+    vf = gst_caps_from_string (vformat);
+  if (aformat)
+    af = gst_caps_from_string (aformat);
+
+  if (G_UNLIKELY ((vformat && (vf == NULL)) || (aformat && (af == NULL))))
+    goto beach;
+
+  prof = create_profile (cf, vf, af);
+
+beach:
+  if (cf)
+    gst_caps_unref (cf);
+  if (vf)
+    gst_caps_unref (vf);
+  if (af)
+    gst_caps_unref (af);
+
+  return prof;
+}
+
+static void
+pad_added_cb (GstElement * uridecodebin, GstPad * pad, GstElement * encodebin)
+{
+  GstPad *sinkpad;
+
+  sinkpad = gst_element_get_compatible_pad (encodebin, pad, NULL);
+
+  if (sinkpad == NULL) {
+    GstCaps *caps;
+
+    /* Ask encodebin for a compatible pad */
+    caps = gst_pad_get_caps (pad);
+    g_signal_emit_by_name (encodebin, "request-pad", caps, &sinkpad);
+    if (caps)
+      gst_caps_unref (caps);
+  }
+  if (sinkpad == NULL) {
+    g_print ("Couldn't get an encoding channel for pad %s:%s\n",
+        GST_DEBUG_PAD_NAME (pad));
+    return;
+  }
+
+  if (G_UNLIKELY (gst_pad_link (pad, sinkpad) != GST_PAD_LINK_OK)) {
+    g_print ("Couldn't link pads\n");
+  }
+
+  return;
+}
+
+static gboolean
+autoplug_continue_cb (GstElement * uridecodebin, GstPad * somepad,
+    GstCaps * caps, GstElement * encodebin)
+{
+  GstPad *sinkpad;
+
+  g_signal_emit_by_name (encodebin, "request-pad", caps, &sinkpad);
+
+  if (sinkpad == NULL)
+    return TRUE;
+
+  return FALSE;
+}
+
+static void
+bus_message_cb (GstBus * bus, GstMessage * message, GMainLoop * mainloop)
+{
+  switch (GST_MESSAGE_TYPE (message)) {
+    case GST_MESSAGE_ERROR:
+      g_print ("ERROR\n");
+      gst_bus_set_flushing (bus, TRUE);
+      g_main_loop_quit (mainloop);
+      break;
+    case GST_MESSAGE_EOS:
+      g_print ("Done\n");
+      g_main_loop_quit (mainloop);
+      break;
+    default:
+      break;
+  }
+}
+
+static void
+transcode_file (gchar * uri, gchar * outputuri, GstEncodingProfile * prof)
+{
+  GstElement *pipeline;
+  GstElement *src;
+  GstElement *ebin;
+  GstElement *sink;
+  GstBus *bus;
+  GstCaps *profilecaps, *rescaps;
+  GMainLoop *mainloop;
+
+  g_print (" Input URI  : %s\n", uri);
+  g_print (" Output URI : %s\n", outputuri);
+
+  sink = gst_element_make_from_uri (GST_URI_SINK, outputuri, "sink");
+  if (G_UNLIKELY (sink == NULL)) {
+    g_print ("Can't create output sink, most likely invalid output URI !\n");
+    return;
+  }
+
+  src = gst_element_factory_make ("uridecodebin", NULL);
+  if (G_UNLIKELY (src == NULL)) {
+    g_print ("Can't create uridecodebin for input URI, aborting!\n");
+    return;
+  }
+
+  /* Figure out the streams that can be passed as-is to encodebin */
+  g_object_get (src, "caps", &rescaps, NULL);
+  rescaps = gst_caps_copy (rescaps);
+  profilecaps = gst_encoding_profile_get_output_caps (prof);
+  gst_caps_append (rescaps, profilecaps);
+
+  /* Set properties */
+  g_object_set (src, "uri", uri, "caps", rescaps, NULL);
+
+  ebin = gst_element_factory_make ("encodebin", NULL);
+  g_object_set (ebin, "profile", prof, NULL);
+
+  g_signal_connect (src, "autoplug-continue", G_CALLBACK (autoplug_continue_cb),
+      ebin);
+  g_signal_connect (src, "pad-added", G_CALLBACK (pad_added_cb), ebin);
+
+  pipeline = gst_pipeline_new ("encoding-pipeline");
+
+  gst_bin_add_many (GST_BIN (pipeline), src, ebin, sink, NULL);
+
+  gst_element_link (ebin, sink);
+
+  mainloop = g_main_loop_new (NULL, FALSE);
+
+  bus = gst_pipeline_get_bus ((GstPipeline *) pipeline);
+  gst_bus_add_signal_watch (bus);
+  g_signal_connect (bus, "message", G_CALLBACK (bus_message_cb), mainloop);
+
+  if (gst_element_set_state (pipeline,
+          GST_STATE_PLAYING) == GST_STATE_CHANGE_FAILURE) {
+    g_print ("Failed to start the encoding\n");
+    return;
+  }
+
+  g_main_loop_run (mainloop);
+
+  gst_element_set_state (pipeline, GST_STATE_NULL);
+  gst_object_unref (pipeline);
+}
+
+static gchar *
+ensure_uri (gchar * location)
+{
+  gchar *res;
+  gchar *path;
+
+  if (gst_uri_is_valid (location))
+    return g_strdup (location);
+
+  if (!g_path_is_absolute (location)) {
+    gchar *cur_dir;
+    cur_dir = g_get_current_dir ();
+    path = g_build_filename (cur_dir, location, NULL);
+    g_free (cur_dir);
+  } else
+    path = g_strdup (location);
+
+  res = g_filename_to_uri (path, NULL, NULL);
+  g_free (path);
+
+  return res;
+}
+
+int
+main (int argc, char **argv)
+{
+  GError *err = NULL;
+  gchar *outputuri = NULL;
+  gchar *format = NULL;
+  gchar *aformat = NULL;
+  gchar *vformat = NULL;
+  gboolean allmissing = FALSE;
+  gboolean listcodecs = FALSE;
+  GOptionEntry options[] = {
+    {"silent", 's', 0, G_OPTION_ARG_NONE, &silent,
+        "Don't output the information structure", NULL},
+    {"outputuri", 'o', 0, G_OPTION_ARG_STRING, &outputuri,
+        "URI to encode to", "URI (<protocol>://<location>)"},
+    {"format", 'f', 0, G_OPTION_ARG_STRING, &format,
+        "Container format", "<GstCaps>"},
+    {"vformat", 'v', 0, G_OPTION_ARG_STRING, &vformat,
+        "Video format", "<GstCaps>"},
+    {"aformat", 'a', 0, G_OPTION_ARG_STRING, &aformat,
+        "Audio format", "<GstCaps>"},
+    {"allmissing", 'm', 0, G_OPTION_ARG_NONE, &allmissing,
+        "encode to all matching format/codec that aren't specified", NULL},
+    {"list-codecs", 'l', 0, G_OPTION_ARG_NONE, &listcodecs,
+        "list all available codecs and container formats", NULL},
+    {NULL}
+  };
+  GOptionContext *ctx;
+  GstEncodingProfile *prof;
+  gchar *inputuri;
+
+  if (!g_thread_supported ())
+    g_thread_init (NULL);
+
+  ctx = g_option_context_new ("- encode URIs with GstProfile and encodebin");
+  g_option_context_add_main_entries (ctx, options, NULL);
+  g_option_context_add_group (ctx, gst_init_get_option_group ());
+
+  if (!g_option_context_parse (ctx, &argc, &argv, &err)) {
+    g_print ("Error initializing: %s\n", err->message);
+    exit (1);
+  }
+
+  if (listcodecs) {
+    list_codecs ();
+    g_option_context_free (ctx);
+    exit (0);
+  }
+
+  if (outputuri == NULL || argc != 2) {
+    g_print ("%s", g_option_context_get_help (ctx, TRUE, NULL));
+    g_option_context_free (ctx);
+    exit (-1);
+  }
+
+  g_option_context_free (ctx);
+
+  /* Fixup outputuri to be a URI */
+  inputuri = ensure_uri (argv[1]);
+  outputuri = ensure_uri (outputuri);
+
+  if (allmissing) {
+    GList *muxers;
+    GstCaps *formats = NULL;
+    GstCaps *vformats = NULL;
+    GstCaps *aformats = NULL;
+    guint f, v, a, flen, vlen, alen;
+
+    if (!format)
+      formats = gst_caps_list_container_formats (GST_RANK_NONE);
+    else
+      formats = gst_caps_from_string (format);
+
+    if (!vformat)
+      vformats = gst_caps_list_video_encoding_formats (GST_RANK_NONE);
+    else
+      vformats = gst_caps_from_string (vformat);
+
+    if (!aformat)
+      aformats = gst_caps_list_audio_encoding_formats (GST_RANK_NONE);
+    else
+      aformats = gst_caps_from_string (aformat);
+    muxers =
+        gst_element_factory_list_get_elements (GST_ELEMENT_FACTORY_TYPE_MUXER,
+        GST_RANK_NONE);
+
+    flen = gst_caps_get_size (formats);
+
+    for (f = 0; f < flen; f++) {
+      GstCaps *container =
+          gst_caps_new_full (gst_caps_steal_structure (formats, 0), NULL);
+      GstCaps *compatv =
+          gst_caps_list_compatible_codecs (container, vformats, muxers);
+      GstCaps *compata =
+          gst_caps_list_compatible_codecs (container, aformats, muxers);
+
+      vlen = gst_caps_get_size (compatv);
+      alen = gst_caps_get_size (compata);
+
+
+      for (v = 0; v < vlen; v++) {
+        GstCaps *vcodec =
+            gst_caps_new_full (gst_structure_copy (gst_caps_get_structure
+                (compatv, v)), NULL);
+        for (a = 0; a < alen; a++) {
+          GstCaps *acodec =
+              gst_caps_new_full (gst_structure_copy (gst_caps_get_structure
+                  (compata, a)), NULL);
+
+          prof =
+              create_profile ((GstCaps *) container, (GstCaps *) vcodec,
+              (GstCaps *) acodec);
+          if (G_UNLIKELY (prof == NULL)) {
+            g_print ("Wrong arguments\n");
+            break;
+          }
+          outputuri =
+              ensure_uri (generate_filename (container, vcodec, acodec));
+          transcode_file (inputuri, outputuri, prof);
+          gst_encoding_profile_unref (prof);
+
+          gst_caps_unref (acodec);
+        }
+        gst_caps_unref (vcodec);
+      }
+      gst_caps_unref (container);
+    }
+
+  } else {
+
+    /* Create the profile */
+    prof = create_profile_from_string (format, vformat, aformat);
+    if (G_UNLIKELY (prof == NULL)) {
+      g_print ("Encoding arguments are not valid !\n");
+      return 1;
+    }
+
+    /* Trancode file */
+    transcode_file (inputuri, outputuri, prof);
+
+    /* cleanup */
+    gst_encoding_profile_unref (prof);
+
+  }
+  return 0;
+}

tests/examples/encoding/gstcapslist.c

@@ -0,0 +1,286 @@
+/* GStreamer
+ * Copyright (C) <2010> Edward Hervey <edward.hervey@collabora.co.uk>
+ *
+ * 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.
+ */
+
+#include "gstcapslist.h"
+
+/*
+ * Caps listing convenience functions
+ */
+
+static gboolean
+remove_range_foreach (GQuark field_id, const GValue * value, GstStructure * st)
+{
+  GType ftype = G_VALUE_TYPE (value);
+  const gchar *fname;
+
+  if (ftype == GST_TYPE_INT_RANGE || ftype == GST_TYPE_DOUBLE_RANGE ||
+      ftype == GST_TYPE_FRACTION_RANGE) {
+    gst_structure_remove_field (st, g_quark_to_string (field_id));
+    return FALSE;
+  }
+
+  fname = g_quark_to_string (field_id);
+
+  /* if (strstr (fname, "framerate") || strstr (fname, "pixel-aspect-ratio") || */
+  /*     strstr (fname, "rate")) { */
+  /*   gst_structure_remove_field (st, g_quark_to_string (field_id)); */
+  /*   return FALSE; */
+  /* } */
+
+  return TRUE;
+}
+
+static void
+clear_caps (GstCaps * caps, GstCaps * rescaps)
+{
+  GstCaps *res;
+  GstStructure *st;
+  guint i;
+
+  res = gst_caps_make_writable (caps);
+
+  GST_DEBUG ("incoming caps %" GST_PTR_FORMAT, res);
+
+  /* Remove width/height/framerate/depth/width fields */
+  for (i = gst_caps_get_size (res); i; i--) {
+    st = gst_caps_get_structure (res, i - 1);
+
+    /* Remove range fields */
+    while (!gst_structure_foreach (st,
+            (GstStructureForeachFunc) remove_range_foreach, st));
+  }
+
+  GST_DEBUG ("stripped %" GST_PTR_FORMAT, res);
+
+  /* And append to list without duplicates */
+  while ((st = gst_caps_steal_structure (res, 0))) {
+    /* Skip fake codecs/containers */
+    if (gst_structure_has_name (st, "audio/x-raw-int") ||
+        gst_structure_has_name (st, "audio/x-raw-float") ||
+        gst_structure_has_name (st, "video/x-raw-yuv") ||
+        gst_structure_has_name (st, "video/x-raw-rgb") ||
+        gst_structure_has_name (st, "unknown/unknown")) {
+      gst_structure_free (st);
+      continue;
+    }
+
+    gst_caps_append_structure (rescaps, st);
+  }
+
+  gst_caps_unref (res);
+}
+
+static GstCaps *
+get_all_caps (GList * elements, GstPadDirection direction)
+{
+  GstCaps *res = NULL, *res2;
+  GList *tmp;
+
+  res = gst_caps_new_empty ();
+
+  for (tmp = elements; tmp; tmp = tmp->next) {
+    GstElementFactory *factory = (GstElementFactory *) tmp->data;
+    const GList *templates;
+    GList *walk;
+
+    templates = gst_element_factory_get_static_pad_templates (factory);
+    for (walk = (GList *) templates; walk; walk = g_list_next (walk)) {
+      GstStaticPadTemplate *templ = walk->data;
+      if (templ->direction == direction)
+        clear_caps (gst_static_caps_get (&templ->static_caps), res);
+    }
+  }
+
+  res2 = gst_caps_normalize (res);
+  gst_caps_unref (res);
+  return res2;
+}
+
+/**
+ * gst_caps_list_container_formats:
+ * @minrank: The minimum #GstRank
+ *
+ * Returns a #GstCaps corresponding to all the container formats
+ * one can mux to on this system.
+ *
+ * Returns: A #GstCaps. Unref with %gst_caps_unref when done with it.
+ */
+GstCaps *
+gst_caps_list_container_formats (GstRank minrank)
+{
+  GstCaps *res;
+  GList *muxers;
+
+  muxers =
+      gst_element_factory_list_get_elements (GST_ELEMENT_FACTORY_TYPE_MUXER,
+      minrank);
+  res = get_all_caps (muxers, GST_PAD_SRC);
+  gst_plugin_feature_list_free (muxers);
+
+  return res;
+}
+
+static GstCaps *
+gst_caps_list_encoding_formats (GstRank minrank)
+{
+  GstCaps *res;
+  GList *encoders;
+
+  encoders =
+      gst_element_factory_list_get_elements (GST_ELEMENT_FACTORY_TYPE_ENCODER,
+      minrank);
+  res = get_all_caps (encoders, GST_PAD_SRC);
+  gst_plugin_feature_list_free (encoders);
+
+  return res;
+}
+
+/**
+ * gst_caps_list_video_encoding_formats:
+ * @minrank: The minimum #GstRank
+ *
+ * Returns a #GstCaps corresponding to all the video or image formats one
+ * can encode to on this system.
+ *
+ * Returns: A #GstCaps. Unref with %gst_caps_unref when done with it.
+ */
+GstCaps *
+gst_caps_list_video_encoding_formats (GstRank minrank)
+{
+  GstCaps *res;
+  GList *encoders;
+
+  encoders =
+      gst_element_factory_list_get_elements
+      (GST_ELEMENT_FACTORY_TYPE_VIDEO_ENCODER, minrank);
+  res = get_all_caps (encoders, GST_PAD_SRC);
+  gst_plugin_feature_list_free (encoders);
+
+  return res;
+}
+
+
+/**
+ * gst_caps_list_audio_encoding_formats:
+ * @minrank: The minimum #GstRank
+ *
+ * Returns a #GstCaps corresponding to all the audio formats one
+ * can encode to on this system.
+ *
+ * Returns: A  #GstCaps. Unref with %gst_caps_unref when done with it.
+ */
+GstCaps *
+gst_caps_list_audio_encoding_formats (GstRank minrank)
+{
+  GstCaps *res;
+  GList *encoders;
+
+  encoders =
+      gst_element_factory_list_get_elements
+      (GST_ELEMENT_FACTORY_TYPE_AUDIO_ENCODER, minrank);
+  res = get_all_caps (encoders, GST_PAD_SRC);
+  gst_plugin_feature_list_free (encoders);
+
+  return res;
+}
+
+/**
+ * gst_caps_list_compatible_codecs:
+ * @containerformat: A #GstCaps corresponding to a container format
+ * @codecformats: An optional #GstCaps of codec formats
+ * @muxers: An optional #GList of muxer #GstElementFactory.
+ *
+ * Returns an array of #GstCaps corresponding to the audio/video/text formats
+ * one can encode to and that can be muxed in the provided @containerformat.
+ *
+ * If specified, only the #GstCaps contained in @codecformats will be checked
+ * against, else all compatible audio/video formats will be returned.
+ *
+ * If specified, only the #GstElementFactory contained in @muxers will be checked,
+ * else all available muxers on the system will be checked.
+ *
+ * Returns: A #GstCaps containing all compatible formats. Unref with %gst_caps_unref
+ * when done.
+ */
+GstCaps *
+gst_caps_list_compatible_codecs (const GstCaps * containerformat,
+    GstCaps * codecformats, GList * muxers)
+{
+  const GList *templates;
+  GstElementFactory *factory;
+  GList *walk;
+  GstCaps *res = NULL;
+  GstCaps *tmpcaps;
+  GList *tmp;
+  gboolean hadmuxers = (muxers != NULL);
+  gboolean hadcodecs = (codecformats != NULL);
+
+  GST_DEBUG ("containerformat: %" GST_PTR_FORMAT, containerformat);
+  GST_DEBUG ("codecformats: %" GST_PTR_FORMAT, codecformats);
+
+  if (!hadmuxers)
+    muxers =
+        gst_element_factory_list_get_elements (GST_ELEMENT_FACTORY_TYPE_MUXER,
+        GST_RANK_NONE);
+  if (!hadcodecs)
+    codecformats = gst_caps_list_encoding_formats (GST_RANK_NONE);
+
+  /* Get the highest rank muxer matching containerformat */
+  tmp =
+      gst_element_factory_list_filter (muxers, containerformat, GST_PAD_SRC,
+      TRUE);
+  if (G_UNLIKELY (tmp == NULL))
+    goto beach;
+
+  factory = (GstElementFactory *) tmp->data;
+
+  GST_DEBUG ("Trying with factory %s",
+      gst_element_factory_get_longname (factory));
+
+  /* Match all muxer sink pad templates against the available codec formats */
+  templates = gst_element_factory_get_static_pad_templates (factory);
+  gst_plugin_feature_list_free (tmp);
+
+  tmpcaps = gst_caps_new_empty ();
+
+  for (walk = (GList *) templates; walk; walk = walk->next) {
+    GstStaticPadTemplate *templ = walk->data;
+
+    if (templ->direction == GST_PAD_SINK) {
+      GstCaps *templ_caps;
+
+      templ_caps = gst_static_caps_get (&templ->static_caps);
+      gst_caps_append (tmpcaps, gst_caps_copy (templ_caps));
+    }
+  }
+
+  res = gst_caps_intersect (tmpcaps, codecformats);
+  gst_caps_unref (tmpcaps);
+
+beach:
+  if (!hadmuxers)
+    gst_plugin_feature_list_free (muxers);
+  if (!hadcodecs)
+    gst_caps_unref (codecformats);
+
+  tmpcaps = gst_caps_normalize (res);
+  gst_caps_unref (res);
+
+  return tmpcaps;
+}

tests/examples/encoding/gstcapslist.h

@@ -0,0 +1,35 @@
+/* GStreamer
+ * Copyright (C) <2010> Edward Hervey <edward.hervey@collabora.co.uk>
+ *
+ * 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.
+ */
+
+#include <gst/gst.h>
+
+GstCaps *gst_caps_list_compatible_codecs (const GstCaps *containerformat,
+					  GstCaps *codecformats,
+					  GList *muxers);
+
+GstCaps *gst_caps_list_compatible_containers (GstCaps *mediaformat,
+					      GList *containerformats);
+
+
+GstCaps *gst_caps_list_container_formats (GstRank minrank);
+
+GstCaps *gst_caps_list_video_encoding_formats (GstRank minrank);
+
+GstCaps *gst_caps_list_audio_encoding_formats (GstRank minrank);
+