buffer: rename PREROLL -> LIVE flag

Rename the GST_BUFFER_FLAG_PREROLL to GST_BUFFER_FLAG_LIVE and give the new flag
a meaning. The old PREROLL flag never had a clear meaning.

gst/gstbuffer.c

@@ -273,7 +273,7 @@ gst_buffer_copy_into (GstBuffer * dest, GstBuffer * src,
     guint mask;
 
     /* copy relevant flags */
-    mask = GST_BUFFER_FLAG_PREROLL | GST_BUFFER_FLAG_IN_CAPS |
+    mask = GST_BUFFER_FLAG_LIVE | GST_BUFFER_FLAG_IN_CAPS |
         GST_BUFFER_FLAG_DELTA_UNIT | GST_BUFFER_FLAG_DISCONT |
         GST_BUFFER_FLAG_GAP | GST_BUFFER_FLAG_MEDIA1 |
         GST_BUFFER_FLAG_MEDIA2 | GST_BUFFER_FLAG_MEDIA3;

gst/gstbuffer.h

@@ -159,26 +159,27 @@ typedef struct _GstBufferPool GstBufferPool;
 
 /**
  * GstBufferFlag:
- * @GST_BUFFER_FLAG_PREROLL: the buffer is part of a preroll and should not be
- * displayed.
+ * @GST_BUFFER_FLAG_LIVE:    the buffer is live data and should be discarded in
+ *                           the PAUSED state.
  * @GST_BUFFER_FLAG_DISCONT: the buffer marks a discontinuity in the stream.
- * This typically occurs after a seek or a dropped buffer from a live or
- * network source.
+ *                           This typically occurs after a seek or a dropped buffer
+ *                           from a live or network source.
  * @GST_BUFFER_FLAG_IN_CAPS: the buffer has been added as a field in a #GstCaps.
- * @GST_BUFFER_FLAG_GAP: the buffer has been created to fill a gap in the
- * stream and contains media neutral data (elements can switch to optimized code
- * path that ignores the buffer content).
+ * @GST_BUFFER_FLAG_GAP:     the buffer has been created to fill a gap in the
+ *                           stream and contains media neutral data (elements can
+ *                           switch to optimized code path that ignores the buffer
+ *                           content).
  * @GST_BUFFER_FLAG_DELTA_UNIT: this unit cannot be decoded independently.
- * @GST_BUFFER_FLAG_MEDIA1: a flag whose use is specific to the caps of the buffer. Since: 0.10.23.
- * @GST_BUFFER_FLAG_MEDIA2: a flag whose use is specific to the caps of the buffer. Since: 0.10.23.
- * @GST_BUFFER_FLAG_MEDIA3: a flag whose use is specific to the caps of the buffer. Since: 0.10.23.
- * @GST_BUFFER_FLAG_MEDIA4: a flag whose use is specific to the caps of the buffer. Since: 0.10.33.
- * @GST_BUFFER_FLAG_LAST: additional flags can be added starting from this flag.
+ * @GST_BUFFER_FLAG_MEDIA1:  a flag whose use is specific to the caps of the buffer. Since: 0.10.23.
+ * @GST_BUFFER_FLAG_MEDIA2:  a flag whose use is specific to the caps of the buffer. Since: 0.10.23.
+ * @GST_BUFFER_FLAG_MEDIA3:  a flag whose use is specific to the caps of the buffer. Since: 0.10.23.
+ * @GST_BUFFER_FLAG_MEDIA4:  a flag whose use is specific to the caps of the buffer. Since: 0.10.33.
+ * @GST_BUFFER_FLAG_LAST:    additional flags can be added starting from this flag.
  *
  * A set of buffer flags used to describe properties of a #GstBuffer.
  */
 typedef enum {
-  GST_BUFFER_FLAG_PREROLL    = (GST_MINI_OBJECT_FLAG_LAST << 0),
+  GST_BUFFER_FLAG_LIVE       = (GST_MINI_OBJECT_FLAG_LAST << 0),
   GST_BUFFER_FLAG_DISCONT    = (GST_MINI_OBJECT_FLAG_LAST << 1),
   GST_BUFFER_FLAG_IN_CAPS    = (GST_MINI_OBJECT_FLAG_LAST << 2),
   GST_BUFFER_FLAG_GAP        = (GST_MINI_OBJECT_FLAG_LAST << 3),

libs/gst/base/gstbasetransform.c

@@ -1464,7 +1464,7 @@ default_copy_metadata (GstBaseTransform * trans,
   priv = trans->priv;
 
   /* now copy the metadata */
-  mask = GST_BUFFER_FLAG_PREROLL | GST_BUFFER_FLAG_IN_CAPS |
+  mask = GST_BUFFER_FLAG_LIVE | GST_BUFFER_FLAG_IN_CAPS |
       GST_BUFFER_FLAG_DELTA_UNIT | GST_BUFFER_FLAG_DISCONT |
       GST_BUFFER_FLAG_GAP | GST_BUFFER_FLAG_MEDIA1 |
       GST_BUFFER_FLAG_MEDIA2 | GST_BUFFER_FLAG_MEDIA3;

libs/gst/dataprotocol/dataprotocol.c

@@ -155,7 +155,7 @@ gst_dp_header_from_buffer_any (const GstBuffer * buffer, GstDPHeaderFlag flags,
 
   /* data flags; eats two bytes from the ABI area */
   /* we copy everything but the read-only flags */
-  flags_mask = GST_BUFFER_FLAG_PREROLL | GST_BUFFER_FLAG_DISCONT |
+  flags_mask = GST_BUFFER_FLAG_LIVE | GST_BUFFER_FLAG_DISCONT |
       GST_BUFFER_FLAG_IN_CAPS | GST_BUFFER_FLAG_GAP |
       GST_BUFFER_FLAG_DELTA_UNIT;