caps: add MIXED capsmixed-caps

MIXED caps have a list of structures and are considered fixed when all
structures are fixed. They can be used to specify caps on a stream that
contains buffers in multiple formats.

4 files changed, 100 insertions, 19 deletions

diff --git a/gst/gstcaps.c b/gst/gstcaps.c
index 51f7ae4e0..50c4cb356 100644
--- a/gst/gstcaps.c
+++ b/gst/gstcaps.c
@@ -56,6 +56,10 @@
  * support one level of nesting. Using more levels will lead to unexpected
  * behavior when using serialization features, such as gst_caps_to_string() or
  * gst_value_serialize() and their counterparts.
+ *
+ * Since 1.6, Mixed caps can be created. These are caps that contain multiple
+ * (fixed) structures that each describe a format. The actual structure that
+ * describes a buffer must be determined in a media specific way.
  */
 
 #ifdef HAVE_CONFIG_H
@@ -93,6 +97,8 @@ typedef struct _GstCapsImpl
 /* same as gst_caps_is_any () */
 #define CAPS_IS_ANY(caps)				\
   (!!(GST_CAPS_FLAGS(caps) & GST_CAPS_FLAG_ANY))
+#define CAPS_IS_MIXED(caps)				\
+  (!!(GST_CAPS_FLAGS(caps) & GST_CAPS_FLAG_MIXED))
 
 /* same as gst_caps_is_empty () */
 #define CAPS_IS_EMPTY(caps)				\
@@ -371,6 +377,33 @@ gst_caps_new_full_valist (GstStructure * structure, va_list var_args)
   return caps;
 }
 
+/**
+ * gst_caps_new_mixed:
+ * @struct1: the first structure to add
+ * @...: additional structures to add
+ *
+ * Creates a new mixed #GstCaps and adds all the structures listed as
+ * arguments.  The list must be %NULL-terminated.  The structures
+ * are not copied; the returned #GstCaps owns the structures.
+ *
+ * Returns: (transfer full): the new mixed #GstCaps
+ *
+ * Since: 1.6
+ */
+GstCaps *
+gst_caps_new_mixed (GstStructure * struct1, ...)
+{
+  GstCaps *caps;
+  va_list var_args;
+
+  va_start (var_args, struct1);
+  caps = gst_caps_new_full_valist (struct1, var_args);
+  GST_CAPS_FLAG_SET (caps, GST_CAPS_FLAG_MIXED);
+  va_end (var_args);
+
+  return caps;
+}
+
 G_DEFINE_POINTER_TYPE (GstStaticCaps, gst_static_caps);
 
 /**
@@ -1090,6 +1123,24 @@ gst_caps_is_empty (const GstCaps * caps)
   return CAPS_IS_EMPTY_SIMPLE (caps);
 }
 
+/**
+ * gst_caps_is_mixed:
+ * @caps: the #GstCaps to test
+ *
+ * Determines if @caps represents a mixed media format.
+ *
+ * Returns: %TRUE if @caps represents a mixed format.
+ *
+ * Since: 1.6
+ */
+gboolean
+gst_caps_is_mixed (const GstCaps * caps)
+{
+  g_return_val_if_fail (GST_IS_CAPS (caps), FALSE);
+
+  return (CAPS_IS_MIXED (caps));
+}
+
 static gboolean
 gst_caps_is_fixed_foreach (GQuark field_id, const GValue * value,
     gpointer unused)
@@ -1105,6 +1156,9 @@ gst_caps_is_fixed_foreach (GQuark field_id, const GValue * value,
  * one structure, and each field in the structure describes a fixed type.
  * Examples of non-fixed types are GST_TYPE_INT_RANGE and GST_TYPE_LIST.
  *
+ * Since 1.6, Mixed caps are allowed to have multiple structures and is fixed when
+ * all of the structures are fixed.
+ *
  * Returns: %TRUE if @caps is fixed
  */
 gboolean
@@ -1115,7 +1169,7 @@ gst_caps_is_fixed (const GstCaps * caps)
 
   g_return_val_if_fail (GST_IS_CAPS (caps), FALSE);
 
-  if (GST_CAPS_LEN (caps) != 1)
+  if (GST_CAPS_LEN (caps) != 1 && !CAPS_IS_MIXED (caps))
     return FALSE;
 
   features = gst_caps_get_features_unchecked (caps, 0);
@@ -2053,8 +2107,8 @@ gst_caps_simplify (GstCaps * caps)
   g_return_val_if_fail (GST_IS_CAPS (caps), NULL);
 
   start = GST_CAPS_LEN (caps) - 1;
-  /* one caps, already as simple as can be */
-  if (start == 0)
+  /* one caps or mixed, already as simple as can be */
+  if (start == 0 || CAPS_IS_MIXED (caps))
     return caps;
 
   caps = gst_caps_make_writable (caps);
@@ -2109,6 +2163,8 @@ gst_caps_simplify (GstCaps * caps)
  * values. First the caps will be truncated and then the first structure will be
  * fixated with gst_structure_fixate().
  *
+ * Mixed caps will have each of the structures be fixated.
+ *
  * Returns: (transfer full): the fixated caps
  */
 GstCaps *
@@ -2116,22 +2172,27 @@ gst_caps_fixate (GstCaps * caps)
 {
   GstStructure *s;
   GstCapsFeatures *f;
+  guint i, len;
 
   g_return_val_if_fail (GST_IS_CAPS (caps), NULL);
 
   /* default fixation */
-  caps = gst_caps_truncate (caps);
+  if (!CAPS_IS_MIXED (caps))
+    caps = gst_caps_truncate (caps);
   caps = gst_caps_make_writable (caps);
-  s = gst_caps_get_structure (caps, 0);
-  gst_structure_fixate (s);
-
-  /* Set features to sysmem if they're still ANY */
-  f = gst_caps_get_features_unchecked (caps, 0);
-  if (f && gst_caps_features_is_any (f)) {
-    f = gst_caps_features_new_empty ();
-    gst_caps_set_features (caps, 0, f);
-  }
 
+  len = GST_CAPS_LEN (caps);
+  for (i = 0; i < len; i++) {
+    s = gst_caps_get_structure (caps, i);
+    gst_structure_fixate (s);
+
+    /* Set features to sysmem if they're still ANY */
+    f = gst_caps_get_features_unchecked (caps, i);
+    if (f && gst_caps_features_is_any (f)) {
+      f = gst_caps_features_new_empty ();
+      gst_caps_set_features (caps, i, f);
+    }
+  }
   return caps;
 }
 
@@ -2160,6 +2221,7 @@ gst_caps_to_string (const GstCaps * caps)
 {
   guint i, slen, clen;
   GString *s;
+  gboolean mixed;
 
   /* NOTE:  This function is potentially called by the debug system,
    * so any calls to gst_log() (and GST_DEBUG(), GST_LOG(), etc.)
@@ -2177,8 +2239,10 @@ gst_caps_to_string (const GstCaps * caps)
     return g_strdup ("EMPTY");
   }
 
+  mixed = CAPS_IS_MIXED (caps);
+
   /* estimate a rough string length to avoid unnecessary reallocs in GString */
-  slen = 0;
+  slen = mixed ? 6 : 0;
   clen = GST_CAPS_LEN (caps);
   for (i = 0; i < clen; i++) {
     GstCapsFeatures *f;
@@ -2192,6 +2256,9 @@ gst_caps_to_string (const GstCaps * caps)
   }
 
   s = g_string_sized_new (slen);
+  if (mixed)
+    g_string_append (s, "(MIXED)");
+
   for (i = 0; i < clen; i++) {
     GstStructure *structure;
     GstCapsFeatures *features;
@@ -2236,6 +2303,11 @@ gst_caps_from_string_inplace (GstCaps * caps, const gchar * string)
     return TRUE;
   }
 
+  if (g_ascii_strncasecmp ("(MIXED)", string, 7) == 0) {
+    GST_CAPS_FLAG_SET (caps, GST_CAPS_FLAG_MIXED);
+    string += 7;
+  }
+
   copy = s = g_strdup (string);
   do {
     GstCapsFeatures *features = NULL;
diff --git a/gst/gstcaps.h b/gst/gstcaps.h
index 4b09b8eb7..ddb487c3d 100644
--- a/gst/gstcaps.h
+++ b/gst/gstcaps.h
@@ -41,11 +41,14 @@ GST_EXPORT GType _gst_caps_type;
  * GstCapsFlags:
  * @GST_CAPS_FLAG_ANY: Caps has no specific content, but can contain
  *    anything.
+ * @GST_CAPS_FLAG_MIXED: the caps contains multiple format
+ *    descriptions, the active format description is media dependent.
  *
  * Extra flags for a caps.
  */
 typedef enum {
-  GST_CAPS_FLAG_ANY	= (GST_MINI_OBJECT_FLAG_LAST << 0)
+  GST_CAPS_FLAG_ANY	= (GST_MINI_OBJECT_FLAG_LAST << 0),
+  GST_CAPS_FLAG_MIXED	= (GST_MINI_OBJECT_FLAG_LAST << 1)
 } GstCapsFlags;
 
 /**
@@ -375,6 +378,8 @@ GstCaps *         gst_caps_new_full                (GstStructure  *struct1,
                                                     ...) G_GNUC_NULL_TERMINATED G_GNUC_WARN_UNUSED_RESULT;
 GstCaps *         gst_caps_new_full_valist         (GstStructure  *structure,
                                                     va_list        var_args) G_GNUC_WARN_UNUSED_RESULT;
+GstCaps *         gst_caps_new_mixed               (GstStructure  *struct1,
+                                                    ...) G_GNUC_NULL_TERMINATED G_GNUC_WARN_UNUSED_RESULT;
 
 GType             gst_static_caps_get_type         (void);
 GstCaps *         gst_static_caps_get              (GstStaticCaps *static_caps);
@@ -421,6 +426,7 @@ void              gst_caps_set_simple_valist       (GstCaps       *caps,
 gboolean          gst_caps_is_any                  (const GstCaps *caps);
 gboolean          gst_caps_is_empty                (const GstCaps *caps);
 gboolean          gst_caps_is_fixed                (const GstCaps *caps);
+gboolean          gst_caps_is_mixed                (const GstCaps *caps);
 gboolean          gst_caps_is_always_compatible    (const GstCaps *caps1,
                                                     const GstCaps *caps2);
 gboolean          gst_caps_is_subset		   (const GstCaps *subset,
diff --git a/gst/parse/parse.l b/gst/parse/parse.l
index 53afba8b6..f9de9abeb 100644
--- a/gst/parse/parse.l
+++ b/gst/parse/parse.l
@@ -72,10 +72,11 @@ _binref {_identifier}[[:space:]]*"."[[:space:]]*"("
 /* links */
 _mimechar [[:alnum:]-]
 _mimetype {_mimechar}+"/"{_mimechar}+
-_capschar ("\\".)|([^\;!])
-_capsstring {_capschar}+
-_caps {_mimetype}(","[^!]|{_capsstring})*
-_link ("!"[[:space:]]*{_caps}([[:space:]]*(";"[[:space:]]*{_caps})*[[:space:]]*)*"!")|("!")
+_structchar ("\\".)|([^\;!])
+_structstring {_structchar}+
+_struct {_mimetype}(","[^!]|{_structstring})*
+_caps ("(MIXED)"[[:space:]]*)?{_struct}([[:space:]]*";"[[:space:]]*{_struct})*
+_link ("!"[[:space:]]*{_caps}[[:space:]]*"!")|("!")
 
 %x value
 %option noyywrap
diff --git a/win32/common/libgstreamer.def b/win32/common/libgstreamer.def
index 2fda6b69f..df617cd8d 100644
--- a/win32/common/libgstreamer.def
+++ b/win32/common/libgstreamer.def
@@ -256,6 +256,7 @@ EXPORTS
 	gst_caps_is_equal
 	gst_caps_is_equal_fixed
 	gst_caps_is_fixed
+	gst_caps_is_mixed
 	gst_caps_is_strictly_equal
 	gst_caps_is_subset
 	gst_caps_is_subset_structure
@@ -268,6 +269,7 @@ EXPORTS
 	gst_caps_new_empty_simple
 	gst_caps_new_full
 	gst_caps_new_full_valist
+	gst_caps_new_mixed
 	gst_caps_new_simple
 	gst_caps_normalize
 	gst_caps_remove_structure