+/**
+ * Add an SEI message to an access unit.
+ */
+int ff_cbs_h264_add_sei_message(CodedBitstreamContext *ctx,
+ CodedBitstreamFragment *access_unit,
+ const H264RawSEIPayload *payload);
+
+/**
+ * Delete an SEI message from an access unit.
+ *
+ * Deletes from nal_unit, which must be an SEI NAL unit. If this is the
+ * last message in nal_unit, also deletes it from access_unit.
+ */
+int ff_cbs_h264_delete_sei_message(CodedBitstreamContext *ctx,
+ CodedBitstreamFragment *access_unit,
+ CodedBitstreamUnit *nal_unit,
+ int position);
+