+/* makes sure that @buf is properly prepared and decorated for passing
+ * to baseclass, and an equally setup frame is returned setup with @buf.
+ * Takes ownership of @buf. */
+static GstBaseParseFrame *
+gst_base_parse_prepare_frame (GstBaseParse * parse, GstBuffer * buffer)
+{
+ GstBaseParseFrame *frame = NULL;
+
+ buffer = gst_buffer_make_writable (buffer);
+
+ GST_LOG_OBJECT (parse,
+ "preparing frame at offset %" G_GUINT64_FORMAT
+ " (%#" G_GINT64_MODIFIER "x) of size %" G_GSIZE_FORMAT,
+ GST_BUFFER_OFFSET (buffer), GST_BUFFER_OFFSET (buffer),
+ gst_buffer_get_size (buffer));
+
+ if (parse->priv->discont) {
+ GST_DEBUG_OBJECT (parse, "marking DISCONT");
+ GST_BUFFER_FLAG_SET (buffer, GST_BUFFER_FLAG_DISCONT);
+ parse->priv->discont = FALSE;
+ }
+
+ GST_BUFFER_OFFSET (buffer) = parse->priv->offset;
+
+ frame = gst_base_parse_frame_new (buffer, 0, 0);
+
+ /* also ensure to update state flags */
+ gst_base_parse_frame_update (parse, frame, buffer);
+ gst_buffer_unref (buffer);
+
+ if (parse->priv->prev_offset != parse->priv->offset || parse->priv->new_frame) {
+ GST_LOG_OBJECT (parse, "marking as new frame");
+ parse->priv->new_frame = FALSE;
+ frame->flags |= GST_BASE_PARSE_FRAME_FLAG_NEW_FRAME;
+ }
+
+ frame->offset = parse->priv->prev_offset = parse->priv->offset;
+
+ /* use default handler to provide initial (upstream) metadata */
+ gst_base_parse_parse_frame (parse, frame);
+
+ return frame;
+}
+
+/* Wraps buffer in a frame and dispatches to subclass.
+ * Also manages data skipping and offset handling (including adapter flushing).
+ * Takes ownership of @buffer */
+static GstFlowReturn
+gst_base_parse_handle_buffer (GstBaseParse * parse, GstBuffer * buffer,
+ gint * skip, gint * flushed)
+{
+ GstBaseParseClass *klass = GST_BASE_PARSE_GET_CLASS (parse);
+ GstBaseParseFrame *frame;
+ GstFlowReturn ret;
+
+ g_return_val_if_fail (skip != NULL || flushed != NULL, GST_FLOW_ERROR);
+
+ GST_LOG_OBJECT (parse,
+ "handling buffer of size %" G_GSIZE_FORMAT " with ts %" GST_TIME_FORMAT
+ ", duration %" GST_TIME_FORMAT, gst_buffer_get_size (buffer),
+ GST_TIME_ARGS (GST_BUFFER_TIMESTAMP (buffer)),
+ GST_TIME_ARGS (GST_BUFFER_DURATION (buffer)));
+
+ /* track what is being flushed during this single round of frame processing */
+ parse->priv->flushed = 0;
+ *skip = 0;
+
+ /* make it easy for _finish_frame to pick up input data */
+ if (parse->priv->pad_mode == GST_PAD_MODE_PULL) {
+ gst_buffer_ref (buffer);
+ gst_adapter_push (parse->priv->adapter, buffer);
+ }
+
+ frame = gst_base_parse_prepare_frame (parse, buffer);
+ ret = klass->handle_frame (parse, frame, skip);
+
+ *flushed = parse->priv->flushed;
+
+ GST_LOG_OBJECT (parse, "handle_frame skipped %d, flushed %d",
+ *skip, *flushed);
+
+ if (ret != GST_FLOW_OK) {
+ GST_DEBUG_OBJECT (parse, "handle_frame returned %d", ret);
+ goto exit;
+ }
+
+ /* subclass can only do one of these, or semantics are too unclear */
+ g_assert (*skip == 0 || *flushed == 0);
+
+ /* track skipping */
+ if (*skip > 0) {
+ GstClockTime timestamp;
+ GstBuffer *outbuf;
+
+ GST_LOG_OBJECT (parse, "finding sync, skipping %d bytes", *skip);
+ if (parse->segment.rate < 0.0 && !parse->priv->buffers_queued) {
+ /* reverse playback, and no frames found yet, so we are skipping
+ * the leading part of a fragment, which may form the tail of
+ * fragment coming later, hopefully subclass skips efficiently ... */
+ timestamp = gst_adapter_prev_timestamp (parse->priv->adapter, NULL);
+ outbuf = gst_adapter_take_buffer (parse->priv->adapter, *skip);
+ outbuf = gst_buffer_make_writable (outbuf);
+ GST_BUFFER_TIMESTAMP (outbuf) = timestamp;
+ parse->priv->buffers_head =
+ g_slist_prepend (parse->priv->buffers_head, outbuf);
+ outbuf = NULL;
+ } else {
+ gst_adapter_flush (parse->priv->adapter, *skip);
+ }
+ if (!parse->priv->discont)
+ parse->priv->sync_offset = parse->priv->offset;
+ parse->priv->offset += *skip;
+ parse->priv->discont = TRUE;
+ /* check for indefinite skipping */
+ if (ret == GST_FLOW_OK)
+ ret = gst_base_parse_check_sync (parse);
+ }
+
+ parse->priv->offset += *flushed;
+
+exit:
+ if (parse->priv->pad_mode == GST_PAD_MODE_PULL) {
+ gst_adapter_clear (parse->priv->adapter);
+ }
+
+ gst_base_parse_frame_free (frame);
+
+ return ret;
+}
+